Home

WinIGS Training Guide - Advanced Grounding Concepts

1. Paes er T kt y 1 Ge Model Ca ae HHH AA ease ee m T qi P we ee a uas M gt ecu f jaw 4 D a PIN sac 5 X X 2X ae ve eae OX VEC ORT as xw eS o oe pm Bs Se es LXI oF Zt 1 x M NS V OK IT Adv 25 3008 i V 1 WinlGS Windows Based Integrated Grounding System Design Program Training Guide Last Revision March 28 2015 Copyright A P Sakis Meliopoulos 2015 NOTICES Copyright Notice This document may not be reproduced without the written consent of the developer The software and document are protected by copyright law see Contact Information Disclaimer The developer is neither responsible nor liable for any conclusions and results obtained through the use of the program WinIGS Contact Information For more information concerning this program please contact Advanced Grounding Concepts P O Box 49116 Atlanta Georgia 30359 Telephone 1 404 325 5411 Fax 1 404 325 5411 Email sakis comcast net Copyright A P Sakis Meliopoulos 2015 Page 2 WinIGS Training Guide Table of Contents Contact Information 2 Table of Contents 3 I Training Guide Overview 5 2 Required System Data 8 3 Creating a Network Model 13 4 Editing the Grounding Model 29 5 Maximum GPR amp Safety Analysis 50 6 Grounding Design Enhancement amp Analysis 68 6 1 Adding a Transmiss
2. Copy Print Help 10 15KV CONCENTRIC 1000 15 00 1000 0 104 5 le Cable Library Editor Manuf kV Phase kcm 1 N A 115KV 1250KCM CU 115 00 1250 0 319 9 1 2 Phelps 115KV 1750KCM AL 115 00 1750 0 552 6 1 3 Phelps 115KV 1750KCM CU 115 00 1750 0 45 8 1 4 N A 115KV 250KCM CU 115 00 2500 82 1 1 9 Phelps 115KV 500KCM CU 115 00 500 0 82 1 1 6 Southwire 138KV750KCM OIL 138 00 750 0 495 5 1 T N A 15KV1000KCM 25 00 1000 0 330 0 1 8 N A 15KV1000MCM 25 00 1000 0 330 0 1 9 WTEC 15KV_CONCENTRIC_1 0 15 00 105 5 45 2 1 Delete Close Sort by Size Sort by Name Sort by Voltage Transmission above 35 kV 11 WTEC 15KV CONCENTRIC 4 0 1500 2116 653 1 12 WTEC 15KV CONCENTRIC 500 1500 5000 1045 1 13 NIA 230KV 1500KCM HPFF 230 00 15000 5685 1 Edit 14 NIA 230KV 2500KCM HPFF 230 00 25000 6574 1 15 N A 230KV1500KCM CU XLPE 23000 15000 1848 1 16 Southwire 230KV1500KCM OIL 230 00 15000 5673 1 17 N A 25KV EPR 500MCM 2500 5000 296 1 18 N A 25KV EPR 750MCM TP 2500 7500 288 1 19 PRYSMIAN 28KV4 0AWG AL 2800 2116 739 1 20 Southwire 3000KCMIL230KV 230 00 5000 6356 1 21 NIA 34KV 1000KCM CU 3400 10000 1232 1 22 NIA 34KV 750KCM CU 3400 5000 1027 1 23 N A 34KV 750MCM CU 3400 5000 1027 1 24 N A 35KV1000KCM 3500 10000 3939 1 25 genenralcable 4 0AL BARELLA1 35 00 2116 84 0 3 C Single Core 26 N A 400KCM 2500 4000 112 1 27 N A 69KV1000KCM AL CE 2500 10000 977 1 Multi Core 28 Southwire 69KV1500KCMOIL 6900 15000 5
3. Copy Print Help Safety Criteria IEEE Std80 2000 Edition BN Close Electric Shock Duration i 0 250 seconds View Plot Permissible Body Current 0 232 Amperes IEEE Std80 2000 Body Weight TOkg 50 kg Probability of Ventricular Fibrillation 0 5 EC Body Resistance 5 c50 95 Probability of Ventricular Fibrillation 0 14 0 5 c 5 9f Touch Voltage 729 7 Volts Hand to Feet feet on soil Step Voltage 22229 Volts c Hand to Hand metal to metal DC Offset Effect Fault Type N A XIR Ratio 0 0000 Faulted Bus N A Decrement Factor 1 0000 Figure 5 9 Safety Criteria Report Form The next step is to plot the touch voltage distribution and compare the results to the maximum allowable touch voltage value Click on the Equipotential and Safety Assessment button Note that two plot frames have been defined gray frames along the perimeter of the substation and commercial grounding systems Double Click on each of these frames to view the plotting parameters illustrated in Figures 5 10 and 5 11 It 1s important to verify that the Reference Group or Terminal for Touch Voltage is correctly set Specifically the touch voltage reference for the substation area should be the MAIN GND group or equivalently the node SUBI_N The touch voltage reference for the commercial ground area should be the DIST group or equivalently the node DIST N WinIGS Training Guide Page 165 101 x
4. WinIGS Training Guide Page 175 B6 3 Inspection of Results In this section we examine the grounding system performance under the worst fault conditions For this purpose close the Maximum GPR or Worst Fault Condition form click on the Reports mode button and select Graphical I O mode Next left double click on the grounding system icon to view the voltage and current report for the grounding system see Figure 6 6 Note that the current into the grounding system is 1 952 kA Since the total fault current is 14 42 kA the split factor is 13 5 Device Graphical I O Report Return Case Transmission Substation Grounding System Design Device Distribution substation grounding system 3 049 kV 65 25D 1 954 kA 65 25D Remote Earth 1 954 kA 65 25D asv Program WinlGS Form FDR_GDIO Figure 6 6 Grounding System Voltage and Current Report Next close the grounding system voltage and current report select the Grounding Reports mode and left double click on the grounding system icon to view the grounding system reports Click on the Grounding Resistance button to view the Grounding system resistance report This report is illustrated in Figure 6 7 Note that the reported resistance at node BUS30 N is 1 56 Ohms Page 176 WinIGS Training Guide Ground System Resistance Report Close Study Case Title Transmission Substation Grounding System Design Grounding System Distribution substation gr
5. Study Case Title Distribution Substation Grounding System Design Resistance srounding System Distribution substation grounding system C Conductance MAIN GND MAIN GND 1 3166 COM 0 4317 DIST 0 5084 Figure 5 7b Grounding System Resistance Matrix Next click on the Resistive Layer Effects button to open the reduction factor computation form illustrated in Figure 5 8 Note that the layer resistivity is set to 2000 Ohm meters and thickness is 0 1 meters The resulting reduction factor is 0 7151 Copy Print Help lal xl STM oo cose Standard c IEEE Std80 1986 c Ref 1 see Help IEEE Std80 2000 1 20 ces Native Soil Upper Layer Resistivity Layer Resistivity 2000 0 Layer Thickness m 0 1000 0 60 Reduction Factor Cs 0 30 k Factor Reduction Factor 0 00 0 050 0 100 0 15 0 20 0 25 Layer Thickness meters Figure 5 8 Reduction Factor Report WinIGS Training Guide Next click on the Close button to close the reduction factor computation form and click on the Allowable Touch and Step Voltages button to open the Safety Criteria computation form illustrated in Figure 5 9 Note that the maximum allowable touch voltage according to IEEE Std 80 for a 0 25 second shock duration and a 50 kg person is reported to be 730 Volts Note also that the computation of the maximum allowable touch voltage has taken into account the X R ratio at the fault location lal x
6. 20 00 35 00 50 00 Total Line Series Impedance amp Shunt Admittance Base 100 0 MVA Real React Real React Magn Phase Zi 0 7798 5 6284 1 0313 7 4435 Ohms 7 5147 Ohms 82 11 Deg Z0 1 6778 13 3304 2 2189 17 6295 Ohms 17 7686 Ohms 82 83 Deg Y1 0 0000 0 7580 0 0000 0 0573 mMhos 0 0573 mMhos 90 00 Deg YO 0 0000 0 4168 0 0000 0 0315 mMhos 0 0315 mMhos 90 00 Deg Surge Impedance ee a Magn Phase E Zi 362 08 Ohms 3 94 Deg ZO 750 88 Ohms 3 59 Deg An Surge Imp Loading MVA 36 52 B Ne Ne Load Carrying Capability A 955 0 c o Bo C2 120 0 feet Other Parameters Computed at Frequency Hz 60 00 Span Length miles 0 10 Soil Resistivity ohm meters 100 00 Tower Ground Resistance ohms 25 00 Program WinlGS Form OHL REP1 Figure 9 3 Transmission Line Sequence Parameters Form Page 196 WinIGS Training Guide Transmission Line Sequence Networks Positive Sequence Network All Values in Ohms 1 031 j 7 443 __ EE 5 0 345 j 34891 4 p p 0 345 j 34891 4 GEM Negative Sequence Network 1 031 j 7 443 B N 0 345 j 34891 4 p l 0 345 j 34891 4 GEM Zero Sequence Network 2 219 j 17 628 u 1 060 j 63460 5 p 1 060 j 63460 5 od Program WinlGS Form OHL REP1C Figure 9 4 Transmission Line Sequence Networks Form Ne
7. 507 7 mA 91 77D 64 22 mV 158 79D 7 167 mA 173 82D 64 22 mV 158 79D 12 79 mA 150 80D le 19 37 mA 19 99D ISV Page 136 Figure 2 2 Graphical I O Report Example WinIGS Training Guide a EXIT Copy Print Help Device Graphical V I Report A Return Case Device Power Flow Analysis Example Transmission Line BUS10 to BUS30 27 62 kW 27 61 kW 214 1 KVAr 17 40 KVAr 44 37 kW 27 36 kW hd 2 195 4 kVAr 17 25 kVAr 10 64 kW 27 64 kW e 195 6 kVAr 17 11 kVAr 805 6 uW 444 5 uW 967 3 uVAr 119 3 uVAr 4 839 mW 813 4 uW e _ e 1 381 mVAr 114 2 uVAr le 131 3 mA 91 19D Ploss 8 661 W le 19 37 mA 19 99D ISV Figure 2 3 Power Flow Report Example Close Power Transformer 115kV 12kV 20MVA 64 04 kV 0 01 D 6 680 kV 30 04 D BUS30 A d td lum n BUS40_A 982 5 mA 29 47 D S 3 613 A 149 40 D 571 4 mA1 59 56D 5 C 3 6134 149 40D 64 04 kV 120 01 D BUS30 B C 976 0 mA 149 49 D 6 681 kV 150 05 D BUS40 B SI 3 522 A 29 77 D 565 9 mA 179 71 D 5 3 522 A 29 77 D 64 04 kV 119 99 D BUS30 C C 9 6 979 1 mA 90 85 D 6 680 kV 89 96 D 4 5 BUS40 C 28 5 3 490 A 90 22 D 564 2 mA 60 19D 2 3 490 A 90 22 D 64 22 mV 158 79 D BUS40 N 118 2 mA 55 97 D Figure 2 4 I
8. Conf Level Conf Level Conf Error Conf Error Conf Error Figure 4 20 Wenner Method 2 Layer Soil Model Parameters Report With 2 bad data removed WinIGS Training Guide Page 49 5 Maximum GPR amp Safety Analysis The maximum ground potential rise analysis performs a large number of fault analysis in order to identify the worst fault i e the fault that causes the maximum GPR at a selected location To perform Max GPR analysis switch to Analysis mode by clicking on the Analysis button and selecting the Maximum Ground Potential Rise option from the pull down menu box see Figure 5 1 amp WinIGS Single Line Diagram Case IGS TGUIDE 01 8 File Edit View Insert Tools Geo Window Help 2a Network Analysis E3 ij Figure 5 1 Setting up for Maximum Ground Potential Rise Analysis Next click on the RUN button to open the Max GPR Dialog Window illustrated in Figure 5 2 Select the node to be monitored for GPR In this example the grounding system of interest is connected to the node named GND N The maximum distance from selected node entry field limits the number of faults to be considered to the ones located within a circle of the specified radius centered on the selected Max GPR node Set this field to zero in order to consider all faults Next click on the Compute button to initiate the analysis Once the analysis is completed the Max GPR Dialog Window reappe
9. Copy Print Help Bac Accept v Active All Modes Earth Voltage Only Cancel Frame Applicability 4 Touch Voltage Only C Step Voltage Only Conductor Voltage Only Touch Voltage Reference Nearest Grounding System Point Model B only User Specified Group or Terminal MAIN GND SUB1_N Step Voltage Distance 3 000 feet C Specify Permissible Voltages Resolution 64 points Equipotential Contours e Linear Number of Contours 10 Logarithmic Number of Decades 3 v Color Code Legend Font Size Factor 1 000 T Opaque Legend Tr Show Enclosed Area Specified Contour C Draw a Contour at 300 000 Volts Figure 5 10 Plot Frame Parameters Form for Substation Grounding System Area MAIN GND group WinIGS Training Guide WinIGS Training Guide Copy Print Help ioj xi r Cancel Accept Coordinates in Feet Equipotential Contours oordinate X1 ZANY Linear lt Logarithmic oordinate Y1 82 000 Number of Contours 10 Number of Decades 3 oordinate X2 106 000 oordinate Y2 14 000 Frame Applicability v Active All Modes Rotation Angle D 0 000 Gee ene egy c Earth Voltage Only Resolution Touch Voltage Only Step Voltage Only IUIIDOE DG EOIDES a Conductor Voltage Only Touch voltage calculations Method 0 Touch Voltage Reference DIST DIST N Step voltage calculations Step Distance feet 3 000 Format Sho
10. ET 0 00 00 NENNT Figure 5 5 Maximum GPR analysis parameters form after analysis is completed The results indicate that the worst fault 1 e the one causing maximum GPR at bus SUBI N isa line to neutral fault at bus SUB1 The GPR is 3 67 kV the fault current is 6 89 kA and the X R ratio at the fault location is 3 66 Next Close this form by clicking on the Close button and proceed to the results inspection section B5 3 Inspection of Results The worst fault analysis described in the previous section terminated with the system solution for the identified worst fault condition In this section we examine the grounding system performance under these conditions Click on the Reports mode button located in the main program toolbar select Graphical I O radio button and left double click on the grounding system icon This action opens the voltage and current report form for the grounding system illustrated in Figure 5 6 Note that the current into the grounding system through the SUBI N terminal is 2 79 kA Recall that the total fault current is 6 89 kA Thus the split factor for this system is 40 5 Note also the transfer voltages to the communication tower COM N and commercial installation DIST N are reported at 1206 V and 1420 V respectively Since the current in these terminals is WinIGS Training Guide Page 161 practically zero you can also compute the grounding system resistance by dividing the GPR by the injected current
11. Ground System Resistance Report Close Study Case Title Generation Substation Grounding System Design Grounding System Distribution substation grounding system Resistance Voltage Current N N N Aon ame oae kame Ohms Volts Amperes MAIN GND BUS30_N 3649 69 6920 93 Figure 7 6 Grounding System Resistance Report WinIGS Training Guide Page 185 Next click on the Resistive Layer Effects button to open the reduction factor computation form illustrated in Figure 7 7 This form models the gravel layer covering the substation yard The existing data represent a 0 1 meters thick layer of gravel of 2000 Ohm meter resistivity Note that if no gravel layer is installed the layer resistivity should be set equal to the native soil top layer resistivity 250 0 Ohm Meters Click on the Update button and then the Close button Reduction Factor IEEE Std80 2000 Edition Update Close Standard O IEEE Std80 1986 O Ref 1 see Help IEEE Std80 2000 1 20 oe Native Soil ge RE Upper Layer Resistivity A 250 0 0 60 Layer Resistivity 2000 0 Layer Thickness m 0 30 0 1000 k Factor 0 7778 0 00 Reduction Factor 0 00 0 050 0 100 0 15 0 20 0 25 0 7258 Layer Thickness meters WinIGS Form GRD RP02 Copyright C A P Meliopoulos 1998 2004 Reduction Factor Cs Figure 7 7 Reduction Factor Report Next click on the Allowable Touch and Step Voltages button to open the Safe
12. Transmission Line Parameters View Diagram Mutually Coupled Transmission lines Bus 20 to Bus 30 Selected Circuit A lt gt Selected Circuit B lt gt From Bus Name BUS30 From Bus Name BUS30 To Bus Name BUS20 To Bus Name BUS20 Circuit CKT1 Circuit CKT2 Section lo of o Section lo of lo Section Length miles 0 000 Section Length miles 0 000 Line Length miles 10 000 Line Length miles 10 000 Operating Voltage kV 115 Operating Voltage kV 115 Insulation Voltage kV 1135 Insulation Voltage kV 1135 Structure Name N A Structure Name N A Year Built N A Year Built N A Phase Conductors Phase Conductors Type Size ACSR CANARY Type Size ACSR CANARY Phase Spacing ft 30 00 15 00 15 00 Phase Spacing ft 30 00 15 00 15 00 Conductors per Bundle 1 Conductors per Bundle 1 Bundle Spacing inches N A Bundle Spacing inches N A Equivalent GMR ft 0 039303 Equivalent GMR ft 0 039303 Resistance Ohms mi 25 C 0 102200 Resistance Ohms mi 25 C 0 102200 Equivalent Diameter inches 1 168230 Equivalent Diameter inches 1 168230 Ground Conductors Ground Conductors _ Type Size HS 5 16HS Type Size HS 5 16HS Number of Ground Cond 1 Number of Ground Cond 2 Spacing ft N A Spacing ft 20 00 Equivalent GMR ft x 1000 0 000365 Equivalent GMR ft x 1000
13. mm 5 ONOonhk wh St k gt Left Click mm 6 Left Click fm 7 Right Click Figure 3 2 Inserting a Transmission Line Model Numbered red arrows illustrate required steps Once the transmission line shape has been finalized left double click on the line to open the line parameter window illustrated in Figure 3 3 Select the appropriate conductor data tower type line length span length pole ground resistance and line operating voltage according to the network data from Figure 2 1 Note that the conductor data and tower type are selected from lists appearing when clicking on the corresponding fields For example Figure 3 4 shows the conductor selection window First select the conductor type on the left column and then the conductor size on from the table on the right side Figure 3 5 shows the tower type selection window Use the radio buttons on the left on the window to narrow down the search to the particular type of tower desired In this example we are looking for H Frame towers so click on the H Frame radio button to reduce the list contents to H Frame towers only Page 14 WinIGS Training Guide Copy Print Help 3 Phase Overhead Transmission Line Cancel Accept 115 kV Line to Bus 10 Auto Title Phase Conductors Type ACSR Size FINCH Type Size 5 16HS Tower Pole Type AGC H 115 Circuit Number 1 Structure Name N A Shields Neutrals
14. 0 000365 Resistance Ohms mi 25 C 9 700000 Resistance Ohms mi 25 C 9 700000 Equivalent Diameter inches 0 221853 Equivalent Diameter inches 0 221853 Distance to Phase Cond ft Distance to Phase Cond ft 20 00 35 00 50 00 15 81 18 03 29 15 29 15 18 03 15 81 Total Line Zero Sequence Series Impedance amp Shunt Admittance Bases 115 0 kV 100 0 MVA Real React Real React Magn Phase E 0 5454 24 5789 0 7213 32 5056 Ohms 32 5136 Ohms 91 27 Deg 0 0000 0 0726 0 0000 0 0055 mMhos 0 0055 mMhos 90 00 Deg Other Parameters Computed at 60 00 Hz Soil Resistivity 100 00 Ohm m Program WinIGS Form OHL REP2 Figure 9 5 Transmission Line Mutual Zero Sequence Parameters Form You can view the transmission line cross section diagram by clicking on the View Diagram button located at the top of this form The transmission line cross section diagram form is illustrated in Figure 9 6 Note that the two selected circuit phases are annotated in red and blue colors Again you can change the selected circuits by clicking on the corresponding buttons Page 198 WinIGS Training Guide Transmission Line Cross Section Mutually Coupled Transmission lines Bus 20 to Bus 30 CKT1 2 CKT2 lt ___ 70 0 feet N1 A1 BI N2 N2 Ct A2 B2 C2 120 0 feet Program WinlGS Form OHL REP2D Figure 9 6 Transmission Line Cross Section Diagram Form
15. 1 000 Ohms Figure 1 6 Resistor Parameter Form Page 116 WinIGS Training Guide In order to inspect the grounding system of this example double click on the grounding system icon Grounding System This action opens the grounding system editor window illustrated in Figure 1 7 The grounding system editor is based on a graphical CAD environment with extensive display and editing capabilities Specifically the grounding system can be displayed in top view side view or perspective view Use the following left toolbar buttons to switch among these viewing modes as follows BE zt Top view See Figure 1 7 Side View Side View Perspective View See Figure 1 8 2 3 4 7e 9 Rendered Perspective View see Figure 1 9 By default the top view of the grounding system 1s shown At any view mode you can zoom using the mouse wheel and pan by moving the mouse while holding down the mouse right button In the perspective view mode you can also rotate the view point by holding down both the keyboard Shift key and the right mouse button Note that the grounding system consists of 6 ground rods and a number of horizontal conductors and a fence The grounding system geometry and the parameters of the grounding conductors can be modified in all views except the Rendered Perspective View Specifically the location and size of the grounding conductors can be graphically changed using the mouse Furthermore conductor parameters can
16. Create Network Model Create Model of Preliminary Ground Design Simulate System at Worst Fault Conditions Max GPR C Edit Mode Analysis Mode 77777777 Reports Mode BERE Modify Grounding and or Network Evaluate Touch amp Step Voltages Design Max Touch amp Step Vo tages NO Below IEEE Std 80 Specs E in E Figure 1 2 Grounding System Design Process It is important to note that a key feature of this approach is the use of an integrated model grounding system network model In many cases the worst fault 1 e the fault that causes the maximum GPR at the design site may be a fault at a different location Modification of the grounding design may change the location and or the resulting fault currents Also in many cases the grounding system performance in the sense of meeting safety standards may be enhanced by modifications outside the physical boundaries of the grounding system under study such as the use of transmission line counterpoises use of larger neutrals and shield conductors in nearby transmission and distribution lines etc Thus an integrated system simulation tool is essential for accurate and efficient execution of the grounding system design process Note that the WinIGS first three operating modes Edit Analysis Reports facilitate the above described design procedure The fourth mode Tools provides several auxiliary features that are not part of the
17. Jacket PPP 0 00 0 20 0 40 0 60 Armor For Help press F1 Active Layer 0 2o as tE Aue i hd 1 o gt E 0560 8 e t PP PPH Layer Group Figure A1 6 Cable Parameters Window Cables can also be created or modified manually by individually adding and manipulating cable components such as conductors insulation jackets etc All the cable components are defined using a number of primitive components namely Conductors Conductor Arrays Conductor Straps and Cylinders i Fi Primitive cable components are introduced using the vertical toolbar button Exc This button opens the insert Cable Component dialog where the desired component to be inserted is selected see Figure A 1 7 The primitive object shapes are illustrated in Figure A1 8 Note that insulation insulation shields and jackets are created using cylinder components Cylinders can also be used to create solid or hollow phase or neutral conductors Each primitive component can be repositioned using the mouse and its parameters can be edited by left double clicking on the object Primitive component parameters include material selection group and layer specification type specification center coordinates and various geometric parameters WinIGS Training Guide Page 83 such as diameters and cross sectional area Figure AI 9 includes two examples of parameter dialog windows for conductor and cylinder components Not that all primitiv
18. Model A Equi Touch Voltage Plot oO A lt E A a perm 22 V Vmax 852 2 V A ESA w RES S7 SARS 7 M99 apf Lo 183 8 V j 250 6 V 317 5 V 451 2 V 518 0 V 584 8 V 651 7 V p 718 5 V p 785 4 V Y P 984 3 V N V 4 m n A SAN N A eh Ce A v y TS z ak r 4 gt ea lC e wo C WA oY Nees area ca NEA NN DHCP SATO I o PM M i 4 O A A F NET m T JN a or e x ww nm 0 Oo WV La A NL E EI Ks TL ars IN runur Distribution Substation Grounding System Scale feet 1 25 2004 IGS AGUIDE CH06 EM feet 0 25 b 75 C Advanced Grounding Concepts WinlGS 1 2 3 i Figure 6 10 Plot Frame Parameters Form for Commercial Installation Grounding System Area DISTR group Next click on the 3D Plot button of the main toolbar and then click on the I button to display the maximum allowable touch voltage plane see Figure 6 11 Note that the actual touch voltage represented by the blue curved surface violates the maximum allowable touch voltage limit represented by the horizontal red plane in a few locations WinIGS Training Guide Page 179 Figure 6 11 Distribution Substation Grounding System At this point you are encouraged to return to edit mode and enhance the grounding system in order to improve its safety performance Enhancements may involve adding grounding conductors in the substati
19. R 3678 V 2794 A 1 32 Ohms O x Copy Print Help Device Graphical V I Report P Ve Return Case Distribution Substation Grounding System Design Device Distribution substation grounding system 1 206 kV 72 90D 0 007 pA 180 00D 1 420 kV 72 90D 0 000 A 0 00D 3 678 kV 72 90D 2 794 kA 72 90D Remote Earth 2 794 kA 72 90D Figure 5 6 Grounding System Voltage and Current Report Next close the grounding system voltage and current report select the Grounding Reports mode radio button and left double click on the grounding system icon This action opens the grounding system viewing window and provides a selection of several grounding system specific reports namely a Grounding Resistance b Resistive Layer Effects c Allowable Touch amp Step Voltages d Voltage amp Current Profiles e Point to Point Impedance and f Bill of Materials Click on the Grounding Resistance button to view the Grounding system resistance report This report is illustrated in Figure 5 7a Note that the reported resistance at node SUBI N is 1 3166 Ohms which is matches the value computed by dividing the GPR by the injected current The report also includes the voltages and currents at each grounding system the total current injected into the earth the fault current and the resulting split factor Note that the reported resistances are the driving point resistances at each component of the grou
20. Tower Pole Ground Impedance Ohms 25 0 X 0 0 Get From GIS m Line Length miles 21 0 Line Span Length miles 0 08 Soil Resistivity Ohm Meters 100 0 AGC 115 kV H Frame Bus Name Side 1 Circuit Number Bus Name Side 2 BUS10 EH 1 SUB 1 Operating Voltage kV 115 0 m Insulation Level kV i FOW Front of Wave N A BIL Basic Insulation Level N A AC AC Withstand N A r Insulated Shields l Transposed Phases l Transposed Shields Read GPS Coordinates n E c 2 Copy Print Help Conductor Library Accept 4 AACTW Figure 3 4 Conductor Selection Window WinIGS Training Guide iat Sort by Name Sort by Size Cancel 5 ACAR 6g ACSR AWG DCRes Area Dia Strands Ampacity 7 ACSRAW 152 CURLEW SD 0 0889 1033 5 1 1910 23 7 1040 8 ACSREHS 153 T2FLYCATCHER 0 0889 1033 5 1 3870 36 2 1188 9 ALUMINUM 154 ORTOLAN SD 0 0896 1033 5 1 1450 22 7 1025 10 ALUMOWE 155 ORTOLAN SSAC 0 0873 1033 5 1 2120 45 7 1050 11 ALU PIPE 156 SNOWBIRD SD 0 0900 1033 5 1 1850 40 7 1025 12 ALU PIPE C 157 FINCH SSAC 0 0808 1113 0 1 2930 54 19 1100 13 BARENEUT 158 BLUEJAY 0 0833 1113 0 1 2580 45 7 1060 14 BOLTS 159 BLUEJAY SD ORT 1113 0 1 2430 41 7 1080 15 COPPER 160 La 1113 eil as 16 COPPERWE 161 17 COPPERWE1 162 IEE 18 COP_CLAD 163 T2PARAKEET 0816 i135 14080 aia i575 19 EHS 164 T2KINGLET 0 0825 1113 0 1 4960 40 14 1254
21. WinlGS Grounding System Geometric Model Case IGS TGUIDE 01 File Edit Select View Insert Transformations Tools Window Help o x J E Grounding Reports E dit Analysis Reports Tools EE s 3 54 uz BD 12 ft 1 1 Grounding Resistive Lauer Allowable Touch Equipotentials amp VoltageCurrent Resistance Effects amp Step Voltages Safety Assessment Profiles Polni te Peir SII aj fetten xx Ex 1 I 2 I 3 7 4 7 6 Fa z i E mmi Grid Spacing 1000 0 ft a 2 Model A Tee GND N MAIN GND Substation X raining Example ST TT Bj yu August 26 2014 Achraneed firmiindinm Ceneente line Cc Advanced Grounding Concepts WinlGs For Help press F1 Figure 5 9 Geometric Ground View Window in Reports Mode Ground Resistance Button This button opens the report window illustrated in Figure 5 10 It lists the ground resistance 0 729 Ohms and the voltage and current flowing to the soil for each grounding group contained in the grounding system model only one in this case It also includes the fault current and the computed split factor 30 8 defined as the ratio of the earth current to the fault current WinIGS Training Guide Page 55 Ground System Resistance Report wae Close Study Case Title Training Guide Power System Grounding System Substatiion X Grounding System Frequency 60 00 Hz Group Name Node Name Resistance Voltage Current Ohms Volts Amperes M
22. neutral voltages should be low and current magnitudes consistent with the system load For example Figure 5 3 shows the voltages and currents at the substation transformer terminals after base case solution was computed 10 x Copy Print Help Device Graphical V I Report Harr Return EL Distribution Substation Grounding System Design SAVES Power Transformer 115kV 42kV 20MVA 66 39 kV 0 03D 6 860 kV 30 35D m 8 680 A 49 11D 126 7 A 130 28D 6 940 kV 150 38D m 1 051 A 164 21D 6 964 kV 90 23D 140 5 mA 2 47D 66 43 kV 119 96D 46 00 V 135 89D e m 8 289 A 124 30D 126 8 A 49 78D Figure 5 3 Base Case Solution Voltage and Current Report The next step is to determine the fault conditions that generate the highest ground potential rise GPR at the substation grounding system in order to verify the system safety under worst possible conditions For this purpose return to the Analysis mode select the Maximum Ground Potential Rise analysis function and click on the Run button This action opens the Maximum GPR analysis parameter form illustrated in Figure 5 4 Select the node to be monitored for maximum GPR to be the node where the WinIGS Training Guide Page 159 substation grounding system is connected i e SUBI N and click on the Compute button 10 xl Copy Print Help Maximum GPR or Worst Fault Conditioi RS Close Study Case Distribution Substation Gro
23. s Manual es WinIGS Grounding System Geometric Model Case IGS TGUIDE 01 Lo miS File Edit Select View Insert Transformations Tools Window Help X a E d it M 0 d e E dit Analysis Reports Tools Win 3 4 i 6 T 8 9 10 11 12 6 96 y 81 68 ft y Grid Spacing 1000 0 ft Model A jJ A GND N MAIN GND 2 E o Q il p mn o Ga raka EFI BEITT Megh Electr Level Freeze Z 4 For Help press F1 Figure 3 1 Ground Editor View with Default Contents 3x2 Rectangular Ground Mat We will begin the construction of the grounding system model in this example by importing the image of the foundation drawing shown in Figure 2 2 This image is also provided as a JPEG file which can be directly imported in the ground editor as a background image We will place the drawing in a dedicated layer so that we can prevent selecting or moving the drawing while we edit the ground model components on top of it To create a named layer and set the layer options such as visibility or preventing edit operations click on the toolbar button to open the Layers window illustrated in Figure 4 2 Not that for each layer this window provides a number of controls check boxes radio buttons etc as well as a text box where the name of the layer can be Page 30 WinIGS Training Guide entered It is recommend to set up a number of named layers to re
24. the fault that results in the highest local current For completeness all types of faults must be considered i e L G L L L L G as well as 3 Phase faults and at all voltage levels present in the system under study One the highest fault current has been determined the Conductor Selection Command can be used to find a conductor that will withstand this current without melting This command is located in the Tools pull down menu while in grounding edit mode See Figure A3 1 amp WinIGS Distribution substation grounding system Case IGS TGUIDE 04 File Edit Select View Insert Transformations Window Help ed Mading Op Edit Mode Modeling Options x 21 70 y 332 19 ft Soi Parameters Reports il np c Maximum Conductor Current Grid Spacing 100 0 ft See Aj Frequency 60 00 Hz Bill of Materials Model A Ground Component List Layers Check Electrode Consistency View Electrode Segmentation BMP to JPG Images GPS Coordinates LSA Options LSA Analysis LSA Tabular Report LSA Graphical Report jb ME La sEEE Clearance Analysis Mechanical Analysis Parameters Mechanical Excitation Parameters Mechanical System Matrix Topology Mechanical Eigenvalue Analysis Mechanical Measurement Elements il E 3 m p d IEEE 605 Wind and Ice Store SDA State G Recall SDA State Il Clear Highlighted Electrodes Blink Highlighted Electrodes H Select Highlighted Electrod
25. 0 00 2 00 4 00 6 00 8 00 BUS10 Distance from BUS10 miles BUS10 to BUS30 Transmission Line BUS10 to BUS30 Circuit 1 GPR Node BUS30_N Update Line to Neutral Fault Type Line to Line to Neutral Close 37 5 Distance 30 0 9 193 kj E GPR kV eo 8 3225 s Fault 50 Current kA 9 682 7 50 DR BUS30 Line to Line to Ground Line to Ground Figure 4 5 GPR and Fault Current versus Fault Location Form The Coefficient of Grounding function generates plots of the coefficient of grounding along any selected circuit as a function of the location To use this function return to the Analysis environment select the Coefficient of Grounding mode select the desired circuit by clicking on it and click on the Run button This action opens the report form illustrated in Figure 4 6 Click on the Update button of the report form to perform the analysis When the analysis 1s completed the traces of the GPR green trace and the coefficient of grounding appear as illustrated in Figure 4 6 See also the Coefficient of Grounding section in the WinIGS users manual WinIGS Training Guide Page 155 f Copy Print Help Coefficient of Grounding Close Distance Phase B ai 0 8805 dips Coefficent of 160 G P R Grounding S 140 Symmetric 22500 Phase B 100 8 ksj i A Coefficent of A o i O 120 15000 pares 5 J EELINB 5 O 149 1 GPR 8
26. 16 Previous Page LPL LIS LISS LL LS Figure A4 13 Selection of Layer of Interest WinIGS Training Guide Page 107 Figure A4 14 illustrates the screen image generated once analysis is completed The exposed area for the substation phase conductors is displayed in meters in the control parameters dialog 1905 m The blue dots indicate the strike origination locations while the red dots indicate the strike termination points for the selected objects i e the phase conductors Note that as always you can rotate or zoom the displayed image using the mouse to obtain any desirable view 3 Rolling Sphere Method 28 Standard IEEE 1985 Historical EPRI Red Book x a Y Exp Area m2 Lightning Current 10 00 k 195 a Sphere Radius 35 7 meters Animation Max Sky Step 5 00 meters Sky Step 18 meters Transpar Auto Scan Stop Clear Traces Close 6S ee LJ Ce o e e e mE MUT LE ee ae and p lt A EMEN US n er Se aa F Figure A4 14 Rolling Sphere Analysis Results Page 108 WinIGS Training Guide Appendix A3 Selection of Ground Conductor Size The size of the conductors comprising a grounding system must be selected so that no conductors will melt during any possible fault conditions Thus the procedure for selecting conductor size starts by performing a fault analysis to determine the worst case fault 1 e
27. Cancel First Node Name Circuit Number 1 SOURCE_A Source Type Voltage Source Current kA Current Source p 6 5 kA i 1 Phase Angle Source Frequency 60 0 Hz 0 0 Degrees Second Node Name SOURCE N Figure 1 4 Device Parameter Form for Source The device parameter forms also allow inspection and modification of other device parameters For example the user editable parameters of the single phase source device illustrated in Figure 1 4 are WinIGS Training Guide Page 115 Parameter Presently Selected Value Source terminal nodes SOURCE A and SOURCE N Source type Current Source Injected Current 6 5 kA Circuit number l The injected current should be the earth or grid current Similarly double clicking on the source ground symbol opens the source ground parameter form which is illustrated in Figure 1 5 Double clicking on the resistor symbol opens the resistor parameter form which is illustrated in Figure 1 6 mo 1ni xj Copy Print Help Source Ground Node Name Circuit Number SOURCE N 2 Resistance 04 Ohms Reactance at Base Frequency 0 0 Ohms Positive for Inductive Negative for Capacitive Reactance Remote Earth Figure 1 5 Source Ground Parameter Form 2 l1Bl x Copy Prit Heip 1 Ohm Resistor Resistance Ohms 1 0 Reactance Ohms 60 Hz 0 0 Circuit Number 1 First Node Name Second Node Name SOURCE_A GRSYS_N
28. Concepts WinlGS 1 3 4 6 7 8 Figure 12 5 Soil Voltage around Cathodic Protection Source Equipotential Plot Figure 12 6 Soil Voltage around Cathodic Protection Source 3 D Surface WinIGS Training Guide Plot Page 215 Appendix B13 Wind Farm Grounding Design amp Analysis This section illustrates the capability of the program WinIGS to perform grounding system design and analysis of a wind farm interconnected to the power grid The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH13 The single line diagram of the example system is illustrated in Figure 13 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results WTUT DHG I 5 MVA Wind Gen System H Figure 13 1 Single Line Diagram of Example System IGS AGUIDE CH13 Four Turbine Wind Farm Page 216 WinIGS Training Guide Grid Spacing 1000 0 ft Model A FG A O S E m EN Ki o NS Scale feet Wind Turbine with Grounding Wind Turbine Generator Grounding System June 13 2008 AGC WTw G 2008 Example 14 C Advanced Grounding Concepts WinlGS Figure 13 2 Grounding System of Example System IGS AGUIDE CH13 Wind Turbine One WinIGS Training Guide Page 217 el Figure 13 3 Grounding System of Example System IGS AGUIDE CH13 Wind Turbine One Pa
29. Edit Analysis Reports cycle Specifically it includes the following WinIGS Training Guide Conductor Library Editor Cable Library Editor Transmission Line Tower Pole Library Editor Smart Ground Meter Export Function Lightning Shielding Analysis Structural Dynamic Analysis Detailed descriptions of the Tools Mode functions can be found in the WinIGS User s Manual This Training Guide presents the use of WinIGS in the grounding system design process outlined above by means of an example The organization of the remaining Sections is as follows Section 2 Presents the data requirements for performing a grounding study of a transmission substation Section 3 Provides step by step guidance in creating the network model of the example system Section 4 Provides step by step guidance in creating the grounding model of the example system Section 5 Describes the Analysis amp Safety Evaluation of the example system using the constructed WinIGS model WinIGS Training Guide Page 7 2 Required System Data Before creating a WinIGS model it is recommended that information regarding the system to be studied is collected The procedure is demonstrated by considering an example of a transmission substation grounding system study The required information for such a system typically consists of e Parameters of major power equipment located on the substation such as power transformers and capacitor banks Typically th
30. Edit Select View Insert Transformations Tools Window Help X bd Edit Mode Edit Analysis Reports Tools ES Wi A 1 Updo peat 162 82 y 272 72 t A in m AB 1 2 3 4 6 T 8 9 10 mmm umimm Grid Spacing 100 0 ft H Model A i X min mium A Ban i mma V E Baler ay B B B E am XL eg 2 C AEA a n a Hy Xy D D Lx Thaw SS wd ae aa EL A iC E E h Tet Group y Depth Ty b s F F SDA Size Meqh Electr _ Level Freeze G G H H J J K K e Substati GND N Su station X L MAIN GND WinlGS Train ng Example L August 26 2014 REV 1 0 G Advanced Grounding Concepts WiniGS 1 2 3 4 5 6 7 8 9 10 Figure 4 12 Ground Editor View with Fence Model and Perimeter Ground Conductor Completed Page 40 WinIGS Training Guide At this point the ground model top view should appear as shown in Figure 4 12 Next we insert a number of horizontal copper conductors within the substation perimeter fence forming a preliminary design of a Ground Mat As a first step a minimalist design is recommended as long as the following minimum requirements are met e It is desirable to place ground conductors near all electrical equipment so that equipment can be conveniently bonded to the grounding system by means of a short pig tail conductor e For all conductors forming the ground mat select a conductor size that will not melt under the highest fault current that may occur in the substation It i
31. Grounding Concepts WinlGS Concepts WinlGS 1 2 3 Figure 12 2 Grounding System of Example System IGS_AGUIDE_CH12 Page 212 WinIGS Training Guide epext Rb ee ANS 7 AMY Weak ora WA sc Cathodic Protection Source x FN j s s N M m N Cathodic Protection Electrodes Figure 12 3 Grounding System of Example System IGS AGUIDE CH12 B12 1 Inspection of System Data Execute the program WinIGS and open the study case titled IGS AGUIDE CHI2 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 12 1 is displayed The example system consists of a generating plant and two transmission lines connecting the plant to the power system The power system beyond the remote end of the two transmission lines is represented by two equivalent sources The generating plant grounding system is modeled in detail see Figures 12 2 and 12 3 It includes a representation of the cathodic protection ground electrodes B12 2 Analysis Click on the Analysis button and select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis 1s completed a pop up window appears indicating the completion of the analysis WinIGS Training Guide Page 213 B12 3 Inspection of Results Cl
32. Layer Soil Model Under Development Wenner Method Four Pin Method Schlumberger Palmer Method Driven Rod Method Three Pin Method Smart Ground Multimeter Data Close Edit Process Figure 1 13 Soil Model Selection Form lolx y Wenner Method Field Data Cancel Accept Isolated Grounding System Example Print Copy Import Export Example Grounding System Default Probe Spacing Probe Length Resistance Apparent Resistivity in Feet a in inches L in Ohms V I Ohm Meters 22215 224 07 210 66 Dynamic Model Fit Report 196 30 100 Raw Measurement 189 60 6 35 000 30 000 2700 18058 245 13 8 4500 3000 1900 16374 19 9 50000 3000 1700 10278 160 87 g Ta t 67 029 E a 153 21 1 4 153 21 j ENS l 16 zl 100m 0 00 20 0 40 0 60 0 80 0 100 Delete Measurement Bad Measurements j Equivalent Separation Distance feet Delete All Measurements Mark Unmark Unmark All DUUPEE REED Hew lone rmi Probe Diameter 0 625 inches e A T Model Corrected Default Probe Length 30 00 inches 2 dove E UpperRho 24375 om Operating Frequency 72 00 Hz v Remove Induced Voltage C pl p2 A Lower Rho 14695 Qm s A Layer Depth 1582 feet Sensitivity 3 Layer Model Fit Soil Model STOP Process r State Limits Objective 0 000000 Figure 1 14 W
33. Miles Compute Both set to zero to consider all faults Worst Fault Condition Circuit Fault OnCircuit 115kVLinetoBus30 1 Fault Type Line to Neutral Fault Fault Location 1 31 miles from bus SUB30 MaxGPR v 17287 XIR Ratio at Fault Location 3 32142 Phases Magnitude kA Phase deg FAULTBUS A 10 4366 106 7086 Fault Current a ET 0 00 03 Figure 6 5 Worst Fault Conditions with Added Counterpoise Ground Page 72 WinIGS Training Guide 1 2 3 Grid Spacing 1000 0 ft Frequency 60 00 Hz Model A gt 4 5 6 7 8 9 10 11 12 13 14 15 Y Equi Touch Voltage Plot with respect to MAIN GND GND_N lx A Vperm 614 5 V Vmax 551 9 V Margin 11 34 B ILS AAA FEE AVAL gt Za E F G H J K L 1322V 458 M iy 225 5 V 212 1 V 918 8V 365 4V 42 0V 458 7V 05 3V p Substation X BAqummu REVO A 105 C Advanced Grounding Concepts WinlGS 4 5 6 7 8 9 10 11 12 13 14 15 Figure 6 6 Touch Voltage Analysis for Worst Fault Conditions with Added Counterpoise Ground WinIGS Training Guide Page 73 6 2 Enhancing the Substation Grounding System We now consider the second alternative of enhancing the substation grounding system in order to reduce touch voltages We begin with the original system model
34. Report Bad Data Removed WinIGS Training Guide Page 125 lt lo xj 2 Layer Soil Model Cancel Accept Study Case Isolated Grounding System Example Grounding System Example Grounding System aa Upper Layer Resistivity 243 75 Ohm meters Lower Layer Resistivity 146 95 Ohm meters Upper Layer Height h 15 82 feet L 4 Figure 1 19 User Specified Soil Model Form B1 2 Analysis of Example System In order to perform the analysis of the example grounding system click on the Analysis button select the Base Case analysis mode from the pull down list default mode and click on the Run button Note that all these controls are located along the top side of the main program window frame Once the analysis 1s completed a pop up window appears indicating the completion of the analysis Click on the Close button to close this window and then click on the Reports button to enter into the report viewing mode Page 126 WinIGS Training Guide B1 3 Inspection of Results While in Reports mode a set of radio buttons appears along the top of the main program window frame which allows selection of the report type From these buttons select the Graphical I O report and then double click on the grounding system icon to view the grounding system Voltage and Current Report This report is illustrated in Figure 1 20 Note that the ground current is 6 5 kA and the voltage 1 e the ground po
35. a short delay the plot illustrated in Figure 11 5 is displayed Note that the impedance reaches a peak of 69 Ohms at 180 Hz 1 e the 3 harmonic in a 60 Hz system The implication of this result is that if a device connected at BUS70 injects 1 Ampere of zero sequence current at the 3 harmonic it will contribute 69 Volts of zero sequence 34 harmonic at BUS80 WinIGS Training Guide Page 209 Transimpedance Report Figure 11 5 Trans Impedance Report Page 210 WinIGS Training Guide Appendix B12 Cathodic Protection Analysis This section illustrates the capability of the program WinIGS to perform cathodic protection analysis The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH12 The single line diagram of the example system is illustrated in Figure 12 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results um 5 PA aii Figure 12 1 Single Line Diagram of Example System IGS_AGUIDE_CH12 Generating Plant WinIGS Training Guide Page 211 Grid Spacing 50 0 ft Model B Biquadratic X Node Indexing Discretization A MAD ee A ATH PROT N A gt A rs Ebr 1B EOE Plant Grounding System Scale feet April 1 2003 AGC 3 2003 1001 50 100 150 C Advanced Grounding Concepts WinlGS Advanced C Advanced
36. across the communications load 1 e across nodes COMMCIR_N and BUS60_N occurs during a Line to Neutral fault at BUS60 The voltage across the communications load during this fault is 1 85 kV You can also inspect the voltages and currents at any point of the system for the computed fault conditions For this purpose close the Maximum Induced Transfer Voltage form and click on the Reports button Double click on the distribution line BUS40 to BUS60 to view the terminal voltages and currents as illustrated in Figure 10 6 WinIGS Training Guide Page 203 Figure 10 7 illustrates an alternative tool for viewing voltages and currents in phasor form This figure is generated as follows Close the voltage and current report click on the Multimeter radio button and again double click on the distribution line from BUS40 to BUS60 On the Multimeter window modify the Multimeter voltage and current nodes as desired to view the corresponding voltages and currents Maximum Transfer Induced Voltage Study Case Induced Transferred Voltage Computations Port Definition Faults Considered From COMMCIR_N oo re Nenial ER T O To Ground Dime Fault Description Circuit Fault On Circuit INA NA Fault Type Line to Neutral Fault Fault Location BUS60 eee Maximum Transfer Induced Voltage kV 18510 X R Ratio at Fault Location 2 3768 Fault Current Magnitude kA Phase deg BUS60 A 1 9174 98 0989 Pr
37. are collected by taking a series of measurements using the arrangement illustrated in Figure 4 15 with various probe spacings a The measurement instrument injects a current 7 circulating between the outer two probes while measuring the voltage V which develops between the inner two probes due to the injected current The measurement instrument reports the measured Resistance defined as R V I in ohms In many cases field reports of such measurements provide the apparent soil resistivity WinIGS Training Guide Page 43 instead of the V I values The apparent soil resistivity p 1s derived from the V I ratio as follows p 2naV iI Either measured resistance or apparent resistivity data can be used with WinIGS to extract a 2 layer soil model The procedure is demonstrated next with the example data of Table 2 1 which consists of 13 measured resistance versus probe spacing measurements 4m TEE a a a Figure 4 15 Wenner Method Arrangement Click om the toolbar button a to open the Soil Data Type Selection window shown in Figure 4 16 Select the radio button titled Wenner Method Four Pin Method then click on the Edit Process button The Wenner Method Field Data window shown in Figure 4 17 opens Enter the Probe Spacing and Resistance data which was provided in Table 2 1 into the first and third columns of this window respectively Then click on the Update button located over the fourt
38. baa besrrPPHk LL For Help press Fl Figure 5 17 Touch Voltage Contours Annotated with Numeric Values After the equipotential plot is completed click on the toolbar button C to insert an equipotential scale element Left click and drag the mouse pointer over the equipotential lines to be annotated This action draws an equipotential scale element which when selected is displayed as a red arrow see Figure 5 17 Page 64 WinIGS Training Guide r WinIGS Grounding System Geometric Model Case IGS TGUIDE 01 File Edit Select View Insert Transformations Tools Window Help i a ld o lt Equipotential Plots Edit Analysis Reports Tools LE x 118 95 y 206 06 ft Touch Voltage 726 8 V v ln i Undo Update Retum 3DPlot STOP C Earh Voltage TouchVolage StepVoltage Conductor y Volege 1 2 3 4 5 6 T 8 a A Grid cing 1000 0 ft A F o Model A 7 m ety ee B D o PP BP p UM n Copy Print Help f Equipotential Scale Cancel Accept Laygr F TN End Point Coordinates Sl ad e a rr Coordinate X1 FEE ft Depth Size i S For Help press F1 Coordinate Y1 205 750 ft B Coordinate X2 120 250 ft Coordinate Y2 207 750 Font Size 2 000 ft Number of Decima
39. be created in one step using the F3 function key After finishing the horizontal conductor entry add vertical ground rods again following im the above recommendations To add ground rods click on the toolbar button mammm to open the insert electrode window Select the 3 row element titled Single Ground Rod ensure that the default layer is Ground Conductors and change the default WinIGS Training Guide Page 41 conductor type and size to COP CLAD 34 then click on the Insert button Click once to insert a single ground rod at the desired location and repeat as necessary Finally insert steel ground mats covering large areas covered with concrete such as a typical control house foundations HINT These elements represent the conductive properties of the concrete typically made with embedded re enforcing steel bars and thus they should not be included in the material list of the grounding system Therefore it is recommended to set these elements in a different Layer such as a Foundations layer so that they will not be included in an automatically generated Bill of Materials For rectangular areas it is most convenient to use the uniform ground mat element Click i on the toolbar button mimm to open the insert electrode window Figure 4 8 Select the 1 row element titled Rectangular Ground Mat ensure that the default layer is set to Foundations and the default conductor type and size is STEEL
40. button E Act Model View Edit Color Dash Page 1 1 c wv v v ME GroundConductors 2 v v ve NN es 3 c wv mv Ww f _ Foundaions J 1 C u ua a r gt o e a a a C ET 6 c re v w aM o T c rp wv r WW loe d Figure 4 6 Layers Window We are now ready to create a preliminary design of the substation grounding system using the provided drawing as a guide The grounding system model will be constructed by inserting a number of Ground Electrode Elements such as bare horizontal buried conductors vertical ground rods connectors and metallic fences See Figure 4 7 for a list of available ground electrode types Before we start creating the model it is important to introduce two fundamental concepts related to ground electrode editing Electrode Group names and the ground editor Snapping modes All ground electrodes are characterized by a number of x y z coordinate triplets that define their shape and position the type and size of the conductor they are made off and the Group and Layer name The ground electrode Group name determines the electrical connection bonding of the electrode to other electrodes in the model Specifically all electrodes sharing a common Group name are assumed to be electrically bonded together Note that each ground electrode is created with the default group name MAIN GNG Thus unless the group names are modified all electrodes are assumed to be bonded together The gr
41. button to close this form The neutral voltages and currents magnitudes can now be seen on the single line diagram as illustrated in Figure 8 2 A S8 S I 4 x A P station 4 a nim a a Yn 3 343 V 15020 Deg BUS3O In 10 77 A 45 14 Deg In 8 737 A 145 63 Deg v D X Sin 3 343 V 150 20 Deg ARAC gt Hx 2 036 A 63 9 Deg Sed EL L O ob w D A q S 8 386 A 99 56 Deg D a AST 8391 A 4282 Deg Figure 8 2 Section of Example Single Line Diagram with Neutral Voltage and Current Displays Note the neutral voltage is highest at BUS60 at 6 049 Volts Also note the earth currents into the grounding systems are in the order of 2 4 Amperes You are encouraged to analyze various stray voltage and current mitigation techniques using the WinIGS model For example you may try the following modifications WinIGS Training Guide Page 191 Rearranging the single phase load phase connections Enhancing the distribution line pole grounding Increasing the distribution line neutral size Enhancing the customer site grounding systems After modifying the system re execute the base case analysis and compare the results Page 192 WinIGS Training Guide Appendix B9 Transmission Line Parameter Computations This section illustrates the capability of the program WinIGS to compute and display the parameters of the various circuits in a system The presentation is based on an exam
42. enter into the report viewing mode Select the Graphical I O mode and double click on all system components to view the voltage and current reports The results should consistent with normal system operation Specifically voltages should be nearly balanced Phase voltage magnitudes should be near nominal values neutral voltages should be low and current magnitudes consistent with the system load Three Analysis functions are demonstrated in this chapter related to Ground Potential Rise computations e Fault Analysis e GPR and Fault Current Versus Fault Location e Coefficient of Grounding The example results of this analysis function are presented in the next section B4 3 Inspection of Results The Fault Analysis example simulates a Phase A to Neutral fault at BUS30 To simulate this fault return to the Analysis environment select the Fault Analysis mode and click on the Run button This action opens the fault definition form illustrated in Figure 4 2 Select the fault definition parameters as indicated in this Figure and click on the Execute button of the fault definition form to perform the analysis Page 152 WinIGS Training Guide la o 2 Copy Print Help Fault Definition Cancel Execute Fault at a Bus cR Fault Type Three Phase Fault Faulted Bus BUS30 C Line to Line to Neutral C Line to Line to Ground Fault on a Circuit Line to Neutral Faulted Circuit Line to Ground IBUS10 to BUS30 T
43. icon of the wind tower one to open the grounding system report mode view Then and as an example select Equipotentials and Safety Assesment Then activate the radio button for touch voltage and click update to view the touch voltage distribution around the tower see Figures 13 8 equi potential graph and 13 9 3 D rendered view Experiment with other reports WinIGS Training Guide Page 223 A ella op paoe d zi l Equi Touch Voltage Plot with respect to MAIN GND WTU1 TWR_N VpermL 242 V Vmax 399 7 V _ D Ep E e A 7 VIN S RESINS LEST ANI N SA pee NNS l ot s i ANZ WON ASS m oe H Dd P ee H FPETM A LLEHE OL DL IX Went SAT TT Am S EI A AAZ 4 5 6 Z bs di Wind Turbine with Grounding enerator G i Wind Turbine Gen r On in erato B June 13 2008 AGC WTw G 2008 Example 14 Advanced Grounding Concepts WinIGS ding System 9 10 Figure 13 8 Touch Voltage Distribution around the Tower Base and the Page 224 Transformer Equipotential Plot WinIGS Training Guide ns Figure 13 9 Touch Voltage Distribution around the Tower Base and the Transformer 3 D Surface Plot WinIGS Training Guide Page 225 Appendix B14 Photovoltaic Plant Grounding Design amp Analysis This section illustrates the capability of the program WinIGS to perform grounding system design and analysis of a photovoltaic farm interconnected to th
44. in the Tools Pull Down menu The bill of materials report 1s shown in Figure 6 8 Next the touch voltage during the worst fault conditions was computed for the enhanced system following the same procedure as described in Section 5 The results are illustrated in Figures 6 9 6 10 and 6 11 Note that the maximum touch voltage has been reduced to 527 Volts which is below the permissible value by a margin of 16 6 and below the target value of 552 Volts The analysis results for the existing system as well as the two enhanced designs are summarized in Table 6 1 Table 6 1 Summary of Touch Voltage Analysis System Counterpoise Ground Mat Ground Improvement Maximum Ground 2341 V 1724 V 2293 V Potential Rise Existing Design 1 Design 2 Maximum Touch 750 V 552 V 527 V Voltage Added Conductor Size amp Length movnpparcr c NR Page 74 WinIGS Training Guide 1 1 3 ia 34 ww q 55 Sm e es Se 4 43e lt A p gg 139 15358 Y Grid Spacing 1000 0 ft A Frequency 60 00 Hz Model A B Saele August 28 2014 REVO 0 as 7o 105 QR Advanced Grounding Concepts WinGS 4 12 ZC A A 2 A ES A A 2 RN 44 1 48 EF L 6 w a a w x 6 m m w 0 w jJ Figure 6 7 Touch Voltage Analysis foe Existing System Yellow color represents touch voltages above the target value of 552 Volts Added Conductors are shown as heavy black lines WinIGS Training Guide Page 75 Bill of Materials i Close Study
45. is recommended that an integrated model be constructed i e a model that includes the grounding system s the equipment in the facility substation generating plant wind turbine system etc as well as the transmission distribution system connected to the facility An integrated model enables the computations of split factor amount of current injection into the ground etc automatically and takes all the guess work out of these computations Appendix B2 provides an example of steady state multiphase power system analysis multiphase power flow analysis Appendix B3 provides an example of short circuit analysis Appendix B4 provides an example for ground potential rise computations Appendix B5 provides an example of grounding system design for a distribution substation Appendix B6 provides an example of grounding system design for a transmission substation WinIGS Training Guide Page 111 Appendix B7 provides an example of grounding system design for a generation substation Appendix B8 provides an example for stray voltage and stray current computations and mitigation techniques for these problems Appendix B9 provides an example of transmission line parameter computations and in particular sequence components and equivalent circuits Appendix B10 provides an example of induced transferred voltages to communication circuits and other wire circuits under the influence of the power system Appendix B11 provides an example of
46. j e L 5 ius n SS P O om Grid Spacing 400 0 f U p 7 Y mmm i I wee n j 7 ay Vi P ip AUN R Clearance Analysis Example __ 3D Substation Model March 19 2015 epts WinlGS vanced Grounding Conc oe a HIR Figure A2 11 Close Up View with Clearance Analysis Results Page 97 WinIGS Training Guide Appendix A4 Lightning Shielding Analysis This Appendix illustrates the capability of the program WinIGS to perform lightning shielding analysis and identification of lightning points of entry The example system WinIGS data files are provided under the study case name IGS_TGUIDE_04 The single line diagram of the example system is illustrated in Figure A4 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results ee eee ON 2 BUS10 BUS30 A BUS40 US x BUS50 V Y 7 N Figure A4 1 Single Line Diagram of Example System IGS_TGUIDE_04 The example system includes two grounding system models one at the distribution substation and one at the end of the distribution line The lightning shielding analysis is demonstrated on the substation grounding system Double click on the substation grounding system symbol to inspect the grounding model geometry Switch
47. model in WinIGS will be demonstrated using an example set of data described above The example data are illustrated in Figures 2 1 through 2 4 and Table 2 1 Figure 2 1 shows the network single line diagram Note that the diagram includes all transmission lines connected to the substation while the system beyond these lines is represented by equivalent sources The diagram includes construction data of the transmission lines transformer name plate parameters and short circuit capacities of the equivalent sources in GVA Page 8 WinIGS Training Guide SCC 1 35 GVA Bus 10 115 kV 4 Transmission Line 21 miles ASCR Finch HS Steel 5 16 iia j i SCC 1 50 GVA Bus 20 230 kV Transmission Line 35 miles 2 x ASCR Pheasant HS Steel 5 16 N IN J Bus 1 Substation X Bus 3 E P Bus 2 Bus 4 M5kV 280 MVA 4 Transmission Line 230 115 kV RES d 42 miles AutoTransformer 52 miles ASCR Finch Delta Tertiary 2 x ASCR Pheasant HS Steel 5 16 Impedance HS Steel 5 16 S P S 5 1 P T 6 5 S T 8 2 at 280 MVA Bus 30 SCC 1 40 GVA For All Lines Assume Average Span Length 0 08 miles Bus 40 SCC 1 80 GVA Average Tower Ground Resistance 25 Ohms Fault Current Level at Substation X 115 kV Bus 3 Ph 11 5 kA L N 13 5 kA 230 kV Bus 3 Ph 6 5 kA L N 8 0 kA Figure 2 1 Network Model Data Wi
48. normalized distance and the titles of the objects involved in the clearance violation The violation normalized distance is defined as the actual distance divided by the minimum permissible distance Thus normalized distances lower than 1 0 constitute clearance violations Clearance violations in the tabular report can be sorted according to the normalized distance by clicking on the Sort button of the Clearance Analysis Report T Close Normalized Permissible Voltage Location Conductor Violating Object Distance Distance ft kV x y in ft 1 0 733 4 00 230 0 0 803 265 2 230 kV Bus Phase C Lightning Pole 2 0 712 6 00 230 0 227 6 203 0 230 kV Phase A Line 100 Fence Post Array 3 0 716 6 00 230 0 227 6 187 0 230 kV Phase B Line 100 Fence Post Array 4 0 710 6 00 230 0 227 6 171 0 230 kV Phase C Line 100 Fence Post Array J 0 886 6 00 230 0 417 0 150 6 230 kV Phase A Line 200 Warehouse 6 0 872 6 00 230 0 681 1 1402 230 kV Phase C Line 200 Soil T 0 880 6 00 230 0 681 1 125 2 230 kV Phase B Line 200 Soil 8 0 884 6 00 230 0 681 1 108 9 230 kV Phase A Line 200 Soil Plot Clearence Vectors None Selection Minimum All Flag Size 1 50 Sort Figure A2 9 Clearance Analysis Report WinIGS Training Guide Page 95 ce Analysis Example Substation Model Figure A2 10 View with Clearance Analysis Results WinIGS Training Guide Page 96 LS p Domo a I a a j ee
49. point you are encouraged to return to edit mode and enhance the system in order to improve its safety performance Enhancements may involve adding grounding WinIGS Training Guide Page 169 conductors in the substation grounding system or enhancing the grounding of the transmission and distribution lines connected to the substation Next repeat the presented analysis procedure to evaluate the enhanced system performance Note that it may be necessary to repeat this analysis enhancement cycle several times before an acceptable safety performance is achieved Page 170 WinIGS Training Guide Appendix B6 Design of Transmission Substation Grounding System This section illustrates the application of the WinIGS program to the analysis and design of a 115kV 230kV transmission substation grounding system The presentation is based on an example system under the study case name IGS_AGUIDE_CH06 The WinIGS data files for this example system are included in the program installation The single line diagram of the example system is illustrated in Figure 6 1 3 Ph EqCkt Figure 6 1 Distribution Substation Example Single Line Diagram The objective of this chapter is to demonstrate the usage of the WinIGS program in transmission substation grounding design Analysis of the example system in its present form indicates that it does not meet IEEE Std 80 safety requirements The user is WinIGS Training Guide Page 171 encouraged to follow
50. the substation grounding system in order to verify the system safety under worst possible conditions For this purpose return to the Analysis mode select the Maximum Ground Potential Rise analysis function and click on the Run button This action opens the Maximum GPR analysis parameter form Select the node to be monitored for maximum GPR to be the node where the substation grounding system 1s connected i e BUS30_N and click on the Compute button When the analysis is completed the Maximum GPR analysis parameter form reappears indicating the worst fault condition as illustrated in Figure 6 5 Maximum GPR or Worst Fault Condition Study Case Transmission Substation Grounding System Design Maximum GPR at Node Faults Considered ToGround set to zero to consider all faults Worst Fault Condition Circuit Fault On Circuit N A N A Fault Type Line to Neutral Fault Fault Location BUS30 Max GPR kV 3 0487 X R Ratio at Fault Location 8 0319 Fault Current Magnitude kA Phase deg BUS30_A 14 4361 82 9233 ET 0 00 04 o ee S WinlGS Form WORST FL Copyright C A P Meliopoulos 1998 2004 Figure 6 5 Fault Conditions for Maximum GPR at node BUS30 N The results indicate that the worst fault i e the one causing maximum GPR at BUS30 N is a line to neutral fault at BUS30 The GPR is 3 05 kV the fault current is 14 4 kA and the X R ratio at the fault location 1s 8 032
51. which the desired cable to import is selected Creates multiple copies of the selected components arranged in a circle To use first select the components to duplicate then click on this button A Page 88 WinIGS Training Guide Button Description dialog window opens where the number of copies and circle origin are specified 2a Move the selected elements to the center of the work area Show all open views Tile Format Zoom in by 20 Zoom so that the entire cable being edited is visible mm m CA ou Zoom out by 20 OL o Zoom into a rectangle defined by a mouse left click drag action Activates or cancels Layer Select mode While in Layer Select mode a left click on one component selects all components with the same layer name Activates or cancels Group Select mode While in Group Select mode a left click on one component selects all components with the same group number Z Displays the edited cable series and shunt admittance matrices WinIGS Training Guide Page 89 Appendix A2 Clearance Analysis The WinIGS geometric ground model permits analysis of conductor clearances Specifically the minimum distances between all modeled conductors rigid or flexible and other objects such as buildings fences antennas lighting poles etc are computed and compared against user specified clearance limits Any identified violations are reported in tabular and graphical form This appendix present the
52. without the counterpoise ground The ground system enhancement consists of adding horizontal ground conductors bonded to the existing system ground mat The design goal is to add just enough ground conductors so that the maximum touch voltage is below the permissible value In order to compare the effectiveness of this approach to the transmission line counterpoise approach let us set the target maximum touch voltage to be the at least as the one achieved with the counterpoise ground namely 552 Volts or an at least an 11 margin below the permissible value of 614 Volts The most effective locations to add ground conductors are the locations where the touch voltage is above our target touch voltage For this purpose we reproduce the touch voltage surface plot for the existing system with the yellow color representing values exceeding the target touch voltage of 552 Volts and the red color representing touch voltages above the permissible value of 614 Volts This plot was captured using the copy drawing command and imported as a background drawing in the ground editor so as to use it as a guide for adding ground conductors The result is illustrated in Figure 6 7 along with the added ground conductors Added conductors are shown as heavy black lines while the existing ground conductors are shown as thin dotted lines Once the ground conductors are added a bill of materials can be automatically generated using the command Bill of Materials located
53. 0 b Three phase fault along transmission line BUSIO to BUS30 4 miles form BUSIO and c Short circuit between high side and low side phase A of the substation transformer BUS30 A to BUSA40 A WinIGS Training Guide Phase B to neutral fault at BUS30 Perform this analysis as directed in the analysis section Once the analysis is completed click on the Reports button to view the analysis results Click on the button to open the Single Line Diagram Report Selector form illustrated in Figure 3 4 Select bus voltage and through variable display fields as indicated in this Figure To modify these fields click on them and select the desired options from the pop up tables Click on the Accept button to close this form The phase voltage and currents magnitudes can now be seen on the single line diagram as illustrated in Figure 3 5 balaj Cancel Accept Bus Voltage Displays SE a fees Color Magnitude Phase A i i Color Magnitude Phase B Result Display Font Size 100 00 i pixels Color Magnitude Phase C Bus Name Font Size 26 Color 0000000000000 jus Name Font Angle 0 degrees Device Icon Size 0 125 Through Variable Displays Color Current Magnitude Phase A Color Current Magnitude PhaseB BUS10 Color Current Magnitude Phase C Color r Hide Series Device Icons r Hide Bus Names r Hide Shunt Devices r Hide Shunt Devic
54. 0 01548 j0 1102 0 00009269 j0 009153 0 004311 j0 02822 0 00006617 j0 008675 0 001599 30 01764 0 001274 j0 01444 0 004845 j0 02884 0 0001567 j0 008989 30 001326 30 021758 0 0002192 j0 008061 0 002451 j0 0004855 0 0008318 j0 0002850 0 001356 j0 0003668 0009603 30 0002913 0 002085 j0 0004336 0 0008500 3j0 0002686 0 0007563 j0 0002645 0 001310 j0 0003714 0 0006316 3j0 0002384 Figure 9 7 Transmission Line Generalized Pi Equivalent Form WinIGS Training Guide Appendix B10 Induced Transferred Voltage Analysis This section illustrates the capability of the program WinIGS to compute induced transferred voltages to communication circuits and other wire circuits that are in the influence of the power system The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH10 The single line diagram of the example system is illustrated in Figure 10 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results Ph Eq Cet ILLE BUS10 Equiv Source Equiv Source BUSTO Y PI Figure 10 1 Single Line Diagram of Example System IGS AGUIDE CH10 B10 1 Inspection of System Data The example system is similar to the one used in chapters 8 and 9 However the distribution line from BUS40 to BUS60 is now represented by the Generalized Tran
55. 0 084 pu 500MVA Stiekt HS 16HS Yellowjacket Substation 12 kV Circuit 3 1 mies 70 70 066 pu 500MVA Tower AGC P 115 35 Ohms Phase AAC ASTER ee Neutral AAC POPPY 3 SQURCE1 ave 30 MVA XFMR 7 8 5 30MVA Tower AGC DP 12 50 Ohms 115 kV Source Z1 72 30 102 pu 500MVA Z0 30 093 pu 500MVA y SSS Sarees SOURCE winga COM per Shiekt HS 6HS Tower AGC H 1 15 35 Ohms Figure 5 1 Distribution Substation Example Single Line Diagram The objective of this chapter is to demonstrate the usage of the WinIGS program in distribution substation grounding design Analysis of the example system in its present form indicates that it does not meet IEEE Std 80 safety requirements The user is encouraged to follow a systematic process of grounding enhancements followed by analysis and repeat this process as necessary for meeting safety requirements WinIGS Training Guide Page 157 Figure 5 2 Distribution Substation Grounding System B5 1 Inspection of System Data In order to run this example execute the program WinIGS and open the study case titled IGS_AGUIDE_CH05 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 5 1 is displayed The system consists of two equivalent sources and source grounds connected at buses SOURCE and SOURCE2 two transmission lines SOU
56. 0 WinIGS Training Guide Copy Print Help General Cable Parameters Name amp Manufacturer Product Name EXAMPLE Manufacturer Company XYZ Classification AWG Metric Electrical Voltage 15 000 kV Ampacity in Duct 300 000 A Ampacity Buried 400 000 A Core DC Resistance Ohms km Shield DC Resistance Ohms km Mechanical Compute Weight 0 000 Ib ft Min Bending Radius 100 0 inches Cancel Accept Figure A1 4 Cable Parameters Window We begin by method a Click on the vertical toolbar button a to open the cable definition wizard illustrated in Figure Al 5 Select the entry field values as shown in the Figure Note that the information needed to complete this task incudes the diameters of the various cable layers insulation insulation shield jacket the conductor and insulating layer materials and the conductor type and sizes All parameters except for the diameters are selected from pop up tables Once the parameters have been set click on the accept button to close the cable wizard and automatically create the cable components The result is illustrated in Figure Al 6 Click on the uj vertical toolbar button to save the created cable into the cable library This completes the creation of a single phase cable WinIGS Training Guide Page 81 m Copy Print Help Define Concentric Neutral Cable IP Conductor Material COPPER Size 4 0 Number of Strands 19
57. 000 Miles Compute Both set to zero to consider all faults Worst Fault Condition Circuit Fault On Circuit 115 kV Line to Bus 30 1 Fault Type Line to Neutral Fault Fault Location 1 31 miles from bus SUB30 Max GPR kv 2 3416 X R Ratio at Fault Location 3 2533 Phases Magnitude kA Phase deg FAULTBUS A 10 4284 107 0880 Fault Current l ET 0 00 01 Figure 5 2 Maximum Ground Potential Rise Dialog Window amp WinIGS Single Line Diagram Case IGS TGUIDE 01 File Edit View Insert Tools Geo Window Help ee A 1j LI ON ion W C Tabular 1 0 C Grounding Reports Circuit Profile Power Flow C EM Field o Solution A 1n Graphicall O Multimeter Internal 1 0 C Power Loss C Harmonics File Substation X Figure 5 3 Selection of Reports Mode For example double clicking on the grounding system symbol opens the report window illustrated in Figure 5 4 which shows the GPR at the substation and the current flowing into the earth through the substation grounding system 4 08 kA WinIGS Training Guide Page 51 Ground System Resistance Report Close Study Case Title Training Guide Power System Grounding System Substatiion X Grounding System Frequency 60 00 Hz Group Name Node Name Resistance Voltage Current Ohms Volts Amperes MAIN GND GND_N 0 7290 2341 61 3212 25 Rp 0 7290 Earth Current 321225 Fault Current 10428 4
58. 1 Split Factor 30 80 Driving Point View Full Matrix Resistance Definition Equivalent Circuit Shunt Branch View Equivalent Ckt Figure 5 4 Voltage amp Current Report for Grounding System Similarly double clicking on other devices the user can obtain the terminal voltages and currents at any device of the simulated system during the fault Figure 5 6 provides an additional example showing the voltages and currents on the faulted transmission line Note that the branches at the bottom of the window represent the fault location is WinlGS Single Line Diagram Case IGS TGUIDE 01 E File Edit View Insert Tools Geo Window Help Edit Analysis Reports Tools ian E M Tabular 10 Grounding Reports Circuit Profile t Power Flow f EM Field soian f Graphical 1 0 Multimeter intemal D Power Loss f Harmonics File m pcm E3 33 A Figure 5 5 Selection of Internal I O Report In addition to device terminal voltages and currents internal currents can be examined on some devices For example the circulating current at the autotransformer delta tertiary winding can be displayed by activating the Internal I O radio button see Figure 5 5 and subsequently double clicking on the autotransformer icon The result is illustrated in Figure 5 7 Note that even though the terminal currents on the delta winding are practically zero the circulating current is 13 37 kA It is important to not
59. 1 2HS then click on the Insert button Click and drag to create a ground mat over the control house area Edit the ground mat properties and select a 7 x 7 mesh See Figure 4 13 then resize element by moving its outside corners as necessary to match the control house area r Copy Print Help Uniform Ground Mat Parameters 12 Accept RectangularGroundMat Cancel Mat Geometry All Dimensions in feet Center X Coordinate 179 750 Center Y Coordinate 125 750 Mesh size along X Direction 11 000 Mesh size along Y Direction EU Number of Meshes along X Number of Meshes along Y Burial Depth positive 1 500 a Conductor Specifications Type STEEL Size 1 2HS Group and Layer Group MAIN GND Layer Foundations Figure 4 13 Rectangular Ground Mat Properties Window An example of a preliminary grounding design configuration is illustrated in Figure 4 14 Page 42 WinIGS Training Guide GND_N MAIN GND Figure 4 14 Preliminary Grounding System Design The remaining task for the completion of the preliminary grounding model is the specification of the soil parameters In this example we will use a two layer soil model derived from field measurement data collected using the Wenner or four pin method Refer back to Table 2 1 which contains a set of Wenner method soil resistivity data The Wenner method
60. 100 7500 22706 Symmetric Coeff of Grounding 80 0 0 00 99 66 0 00 2 00 4 00 6 00 8 00 10 0 BUS10 Distance from BUS10 miles BUS30 U pdate Circuit BUS10 to BUS30 Transmission Line BUS10 to BUS30 Circuit 1 Nominal L L Voltage kV 115 00 A nifi L N L N Definition of Unfaulted Fault Type ib Faulted Phase pB Phase Voltage L G E cC c Absolute Figure 4 6 Coefficient of Grounding Form Page 156 WinIGS Training Guide Appendix B5 Design of Distribution Substation Grounding System This section illustrates the application of the WinIGS program to the analysis and design of a 115kV 12kV distribution substation grounding The presentation is based on an example system under the study case name IGS_AGUIDE_CH05 The WinIGS data files for this example system are included in the program installation The single line diagram of the example system is illustrated in Figure 5 1 A 3 D view of the distribution substation grounding system is illustrated in Figure 5 2 Note that in addition to the substation grounding system large fenced area the model includes a nearby commercial facility grounding system smaller fenced area and a communication tower ground consisting of two counterpoises and a ground rod However the emphasis in this section is performance analysis and design of the substation grounding system 115 kV Line 18 2 miles 115 kV Source Phase ACSRIORIOLE 71 22 3
61. 20 HS 165 RAIL OD 0 0790 1158 0 1 1650 33 7 1090 E 21 OPGW 166 GRACKLE SSAC 0 0754 1192 5 1 3380 54 19 1150 22 OPTGW 167 OXBIRD SD 0 0780 1192 5 1 2660 39 7 1120 23 RAILROAD 168 GRACKLE SD 0 0770 11925 1 2740 26 19 1135 24 STEEL 169 T2KITTIWAKE 0 0771 1192 5 1 4900 36 2 1304 25 STL PIPE 170 BUNTING 0 0777 11925 1 3020 45 7 1110 26 ST STEEL LA BUNTING SD 0 0776 1192 5 1 2840 41 7 1125 J mE Resistance in ohms mile area in cmils diameter in inches ampacity in A Page 15 Page 16 z koae Copy Print Help Tower Library 4 Cancel Accept Structure 1 101A C All 2 102D C Custom 3 C Lattice 4 AGC H 115 C H Frame 5 AGC H 115B Trans Pole 6 AGC H 150 S C Distr Pole E AGC H 161 Phases 8 AGC H 161B C Any 9 AGC H 161U CH 10 AGC H 230 s 11 AGC H 230B a 12 AGC H 230T ers 13 AGC H 345B 67 8 feet Neutrals 14 AGC H1 230B 15 AGC H2 230B Any 16 ATC 05 S 17 ATC 22 ES 18 ATC 30 19 BCH HFRAME 69 NS Bundles 20 BCHYDRO H 230 Any 21 BCHYDRO H 345 C 22 C 118280S uS NEHMEN PapccpMHNG C2 23 CP amp L230H 2 24 CP amp L230HB2 AGC 115 kV H Frame Figure 3 5 Transmission Line Tower Selection Window The transmission line parameters shown in Figure 3 3 are for the 115 kV line connecting the study substation to Bus 10 Continue in the same way and enter the data for the remaining three transmission lines Hint You can use copy and paste to create the next 115 kV line This reduces the a
62. 4 0000 55 5000 4 SUBIOXN SUBION CKTi HS 5 16HS 0 YES 7 7500 677500 6 CIENCIAS RUN NN RIS OL VES 100 67 50 6 SUB10X N SUBIO N CKT COPPER 2 0 0 0 5 0 Tower NO AGC H Circuit Numbe De Circuit Name ICKT1 Side 1 Node Name SUB10X_N Side 2 Node Name SUB10_N Conductor Type COPPER Conductor Size 2 0 Number of Subconductors 1 Subconductor Separation inches 0 Insulated Conductor iv Bonded to Grounds X Coordinate feet 0 0 Y Coordinate feet 5 0 This Conductor Cancel Apply to This Circuit C All Circuits Multiphase Line Model Page 71 Next repeat the maximum ground potential rise analysis to evaluate the effect of the added counterpoise to the ground potential rise and the maximum touch voltage The analysis procedure is identical as the one presented in Section 5 Figures 6 5 and 6 6 illustrate the results Note that with the addition of the counterpoise ground the maximum GPR has been reduced from 2 34 kV to 1 72 kV and the maximum touch voltage from 750 Volts to 552 Volts Since the permissible touch voltage is 614 volts the system now meets the IEEE Std 80 touch voltage limit with a 11 3 margin Maximum GPR or Worst Fault Condition crc Close study Case Isolated Grounding System Example Maximum GPR at Node Faults Considered Maximum Distance From GND_N Sra Tre To Neutral To Ground 0 000
63. 4 11D 112 1 A 37 30D 70 32 kV 1 06D 114 7 A 141 14D us kV 171 53D 56 25 kV 1 m E 4 515 kA 12 12D 4 513 kA 167 89D 77 02 kV 102 97D 63 35 kV 117 56D lt a e 92 69 A 42 73D 93 84 A 139 26D 4 634 kV 171 53D 1 071 kA 177 18D 3 224 kV 19 78D 778 7 A 1 98D 4 634 kV 171 53D 1 052 kA 179 47D 3 224 kV 19 78D md 761 5 A 1 20D le 2 702 kA 155 02D Ploss 65 05 MW le 3 224 kA 19 78D ISV Figure 3 7 BUS20 to BUS30 Terminal Transmission Line Voltages and Currents during a Phase B to neutral fault at BUS30 WinIGS Training Guide Page 145 Copy Print Help Device Graphical V I Report Return ETT Short Circuit Analysis Example System EST Distribution Line 12 kV BUS40 to BUS60 2 991 kV 61 87D 117 6 A 41 87D 9 869 kV 177 71D O 192 8 A 178 75D ve kV 135 23D 149 2 A 114 47D 4 634 kV 171 53D 1 873 kA 132 87D le 2 033 kA 44 86D 4 072 kV 30 26D 117 6 A 138 05D 7 296 kV 174 68D a o 192 8 A 1 30D 6 379 kV 112 88D 149 2 A 65 58D 807 5 V 84 92D 360 7 A 123 52D Ploss 6 957 MW le 363 8 A 84 92D ISV Figure 3 8 BUS40 to BUS60 Distribution Line Terminal Voltages and Currents during a Phase B to neutral fault at BUS30 Lo 5 mE Transmi
64. 4 27 D 121 5 kV 115 03 D mE XF 2 B 878 3 A 106 53 D E x E e 13 37 kA 107 08 D 132 5 kV 112 74 D 8 XF2 C 876 6 A 1104 79 D E c XF 3_A 117 2 pA 165 96 D 11 07 kV 74 17 D XF 3 B 359 5 pA 18 43 D 10 02 kV 116 14 D XF 3 C 85 27 pA 90 00 D 20 50 kV 30 40 D XF 1 A 7 302 kA 106 23 D z 13 37 kA 107 08 D 60 06 kV 115 94 D XF 1 B 1 021 kA 108 51 D 67 34 kV 112 87 D 2 342 kV 106 96 D XF 1_C XF 2_N 1 036 kA 110 57 D 8 847 kA 72 99 D Figure 5 7 Internal I O Report for Autotransformer In order to perform safety analysis select the Grounding Reports radio button as shown in Figure 5 8 and double click on the grounding icon to open the geometric grounding system window shown in Figure 5 9 Note that the program is in Reports Mode and a row of buttons now appears below the mode selection buttons These buttons provide a number of reports that characterize the performance of the grounding system These reports are described next lS WinIGS Single Line Diagram Case IGS TGUIDE 01 LE File Edit View Insert Tools Geo Window Help M E ut o Reports E dit Analysis Reports Tools a ion Ex bal C Tabular 1 0 Grounding Reports Circuit Profile C Power Flow EM Field salts i i C i i i i i Graphical 10 Multimeter Internal 70 Fower Loss Harmonics File Figure 5 8 Grounding Report Selection Page 54 WinIGS Training Guide k
65. 4 5 6 T 8 9 Figure 5 13 Rectangular and Polygonal Plot Frame Toolbar Buttons and example of polygonal frame defining equipotential voltage computation area WinIGS Training Guide The user controls on this window include Active Checkbox Check this box to enable updating the equipotential plots whenever the Update button is clicked See also Figure 5 13 Frame Applicability Radio Buttons These radio buttons limit the use of the associated plot frame to a specific display quantity For example in most cases touch and step voltages must be evaluated at different regions Thus you can create two or more different plot frames and assign each one to plot a different quantity m rc m Copy Print Help Voltage Plot Polygonal Frame ANE Accept Active c All Modes Cancel ELE Earth Voltage Only Applicability Touch Voltage Only Z 0 000 ft C Step Voltage Only Conductor Voltage Only Touch Voltage C Nearest Grounding Point Not for Model A Reference User Specified Group or Terminal MAIN GND GND_N Step Voltage Distance r Specify Permissible Voltages Equipotential Contours Resolution 200 points Contours 10 Linear Decades 3 Log Legend Color Code Legend T Opaque Legend T Show Enclosed Area T Draw a Contour at Font Size 300 000 Volts 1 000 Figure 5 14 Polygonal Plot Frame Parameters Dialog Window Touch Voltage Reference Use these controls to define the group or te
66. 8 Stray Current Analysis and Control B8 1 Inspection of System Data B8 2 Analysis B8 3 Inspection of Results Appendix B9 Transmission Line Parameter Computations B9 1 Inspection of System Data B9 2 Analysis Appendix B10 Induced Transferred Voltage Analysis B10 1 Inspection of System Data B10 2 Analysis B10 3 Inspection of Results Appendix B11 Harmonic Propagation Computations B11 1 Inspection of System Data B11 2 Analysis Appendix B12 Cathodic Protection Analysis B12 1 Inspection of System Data B12 2 Analysis B12 3 Inspection of Results Appendix B13 Wind Farm Grounding Design amp Analysis B13 1 Inspection of System Data B13 2 Analysis Steady State Operation B13 3 Analysis Maximum Ground Potential Rise Appendix B14 Photovoltaic Plant Grounding Design amp Analysis 159 161 171 172 174 176 181 182 182 184 190 190 191 191 193 194 194 201 201 202 203 206 206 207 211 213 213 214 216 219 219 220 226 WinIGS Training Guide 1 Training Guide Overview This manual presents a step by step training approach for the WinIGS program user WinIGS is a software tool for the design and analysis of multiphase power systems with emphasis on grounding and electromagnetic compatibility The program supports the IEEE Std 80 safety criteria as well as the IEC criteria for grounding system safety The WinIGS program has four operating modes The Edit Mode The
67. 8 0 27830 3906 0 6280 12 ALU PIPE EE E 5 INCH 0 1450 1070 7 1 0348 13 ALU PIPE C 14 BARENEUT 15 BOLTS 16 COPPER 17 COPPERWE 18 COPPERWE1 10 COP_CLAD 20 EHS 21 HS 22 OPGW 23 OPTGW 24 RAILROAD 25 STEEL 26 STL PIPE 27 ST STEEL b z Resistance in ohms mile area in cmils diameter in inches ampacity in A Figure 1 12 Conductor Library An other important set of grounding system parameters are the soil model parameters In this example the soil model 1s derived from soil resistivity field measurements The field measurements were obtained using the Wenner method a k a the four pin method The WinIGS program accepts Wenner method field data and automatically estimate the parameters of a two layer soil model A set of Wenner method data have been already stored in this example s data files You can inspect or edit the Wenner method data by clicking on the toolbar button ma l This action opens the Soil Resistivity Data Interpretation form illustrated in Figure 1 13 Next select the Wenner Method option and click on the Edit Process button to open the Wenner Method Field Data entry form This form is illustrated in Figure 1 14 WinIGS Training Guide Page 121 Banx Copy Print Help Soil Resistivity Data Interpretation Study Case Isolated Grounding System Example Grounding System Example Grounding System Soil Data Type User Specified 2 Layer Soil Model c User Specified 3
68. 984 1 C Conduit 29 N A 69KV2000KCM AL OF 6900 5000 45600 1 30 N A 69KV2000KCM AL OIF 6900 20000 11100 1 All 31 N A 69KV2000KCM CU XLPE 6900 20000 1657 1 32 KERITE 69KV250KCM CU TAPE5M 2500 250 0 375 1 Secondary up to 600 V 33 SOUTHWIRE 750KCM AA 3450 7500 1567 1 DRE 34 ABB ABB 110 1013AL 110 00 1000 0 1943 1 C Distribution up to 35 kV 35 ABB ABB 135KV 3000SEGCU 13500 30000 137 1 1 36 ABB ABB 138KV 1000CMPCU 138 00 19740 6955 1 37 ABB ABB 230KV 2500CMPCU 230 00 49340 5842 1 amp All 38 ABB ABB 230KV 2500SEGCU 230 00 49340 5813 1 New C AWG Metric All Figure A1 2 Cable Library Editor List Window WinIGS Training Guide Page 79 e WinlGS i z A i 7 File Edit View Insert Window dep E x Ld Tools Edit Analysis Reports Tools a S Conductor Library Cable Library Tower Library A ES Fuse Library Mat Lib Section Lib x 0 302 y 4 435 r 4 446 Name pod Manufacturer H Electrical Parameters Voltage 15 000 kV CY Ampacity in Duct 300 A Ampacity Buried 400 A Mechanical Parameters Sas Min Bending Radius 32 808 feet E Weight 1 000 1b ft Er Conductor Parameters A Number of Phases 0 Area 0 0 KCM E Number of Strands 0 Diameter 0 000 inches j Resistance 1 410 Ohms mile oto Material o o basi Insulation Parameters 2C 2 Diameter 0 000 inches cpu a IE xD CI M a Oa Permitivity 0 000 Material a Neutra
69. AGUIDE_CH08 B8 1 Inspection of System Data Execute the program WinIGS and open the study case titled IGS_AGUIDE_CH08 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 8 1 is displayed The example system consists of two transmission lines one equivalent line two equivalent sources a delta wye connected transformer a 12 kV distribution system loop with an open switch in the loop three phase loads as well as single phase loads along the distribution system and appropriate grounding Inspect the device parameters and specifically the distribution system components Note the single phase load distribution the size of the distribution neutrals the grounding of the distribution lines and load sites Page 190 WinIGS Training Guide B8 2 Analysis In order to examine stray voltages and currents under normal operation a Base Case solution must be computed Click on the Analysis button select the Base Case analysis mode and click on the Run button Once the analysis is completed click on the Reports button to enter into the report viewing mode B8 3 Inspection of Results Click on the button to open the Single Line Diagram Report Selector form Select displays of bus neutral voltages and line neutral currents through variable display fields Click on the Accept
70. AGUIDE_CH15_P FARM CO Figure 3 1 Case Creation Dialog Window Upon creating a new case the program opens a blank Network Editor View Window You are now ready to create the network model Refer to Figure 2 1 for the network model data Begin by creating the four transmission lines comprising the model The steps for inserting a transmission line are illustrated in Figure 3 1 and summarized below 1 Click on the toolbar button element selection table insert series device to open the series 2 Select the first table entry titled 3 Phase Overhead Transmission Line Click on the Accept button WinIGS Training Guide Page 13 4 5 6 Use the left mouse button and click at the desired points to locate the transmission line diagram You can draw as many vertices as desired to form the line shape I Use the Right mouse button to terminate the transmission line point entry es WinIGS Single Line Diagram Case IGS TGUIDE 01 A File Edit View Insert Tools Geo Window Help E S E dit Analysis Reports Tools 8 LJ x27B y 44 e ip PPUSXITS UE Copy Print Help Select Device Cancel Description Series R L or R C Model Equivalent Circuit Sequence Parameters 3 Phase Mutually Coupled Multi Phase Lines Multisection 3 Phase Transmission Line Concentric Neutral URD Cable OBSOLETE Multiphase Cable Model Mutually Coupled Inductors Left Click mm 4 Left Click
71. AIN GND GND_N 0 7290 2341 61 3212 25 Rp 0 7290 Earth Current 321225 Fault Current 10428 41 Split Factor 30 80 EF Driving Point View Full Matrix e Resistance Definition Equivalent Circuit Shunt Branch View Equivalent Ckt Figure 5 10 Grounding System Resistance Voltage amp Current Report Resistive Layer Effect Button This button opens the Reduction Factor window illustrated in Figure 5 11 The reduction factor is used in the permissible touch and step voltage computations to take into account the effects of an insulating layer that may exist over the grounding system such as a crushed rock or an asphalt layer The input data needed for these computations are 1 the insulating layer thickness in meters and the insulating layer material resistivity in ohm meters Once these two data are entered the reduction factor is computed and displayed It is also automatically used in the permissible touch and step voltage computations described in the next section In this example we used a crushed rock layer of 2000 Ohm meter resistivity and 0 1 meter thickness resulting in a reduction factor of 0 7244 This result depends also on the native top layer resistivity which is 243 7 Ohm meters Note that the window also contains a set of radio buttons which select the standard used for the reduction factor computations It is recommended to always use the IEEE Std 80 2000 option The other two options are from older stand
72. Analysis Mode The Reports Mode The Tools Mode The user can switch between these modes at any time by clicking on the corresponding buttons located at the top of the main program window See Figure 1 1 A typical program session starts at the Edit mode where both network topology and ground system models are defined Next the Analysis mode is selected and the desired computations are performed Finally the Reports mode is selected in order to view the results of the analysis This program organization facilitates the design process outlined in Figure 1 2 The design process begins with a preliminary grounding design This design is simulated by an integrated model which includes the grounding system along with the major power devices of the power network in the vicinity of the grounding system under study The simulation involves performing multiple fault analyses in order to determine the worst fault conditions 1 e the fault that generates the highest ground potential rise GPR at the design site Next the touch and step voltages during worst fault conditions are evaluated and compared with allowable values according to IEEE Std 80 or IEC 479 If the actual touch and step voltages exceed the allowable values the grounding system design is modified and process is repeated until the standards are met Operating Mode Buttons Figure 1 1 WinlGS Operating Mode Selection Buttons WinIGS Training Guide Page 5
73. B C c D D E E F IF G G l 1 J f K K L IL M M N IN 266 7V O 310 2 V j 353 6V P 897 0 V P j 440 4 V E Q 483 8 V Q Substation X WinlGS Training Example R August 26 2014 ReEv10 R 0 35 70 105 C Advanced Grounding Concepts WinIGS 112 3 4 5 e J 7 8 9 10 11 12 13 14 15 16 Figure 6 11 Touch Voltage Equipotential Plot for Enhanced System Page 78 WinIGS Training Guide Appendix A1 Using the Cable Library Editor The cable library editor allows creating and modifying both single and multicore cable models The cable library editor is accessible by switching to Tools Mode and clicking on the Cable Library button see Figure below which opens the Cable Library List window 8 File Edit View Insert Tools Geo Window Help y am Tools Edit Analysis Reports Conductor Library Cable Library Tower Library Circuit Parameters Export to SGM Lightning Shielding Mechanical Fal Fuse Library Section Lib Protection Coord 160 y 6 Figure A1 1 Starting the Cable Library Editor The Cable Library List window is illustrated in Figure A1 2 It contains a list of the existing cables and several buttons for editing and inserting new cables as well as sorting the cable list according to various criteria The use of the cable editor 1s illustrated by examples in this section 2 Ne pu E
74. Case Training Guide Power System Grounding System Grounding System Geometric Model Layers THO Multiple All Layer Type and Size Quantity COPPER 4 0 1322 00 feet Exothermic Connector 2 0 to 4 0 7 Exothermic Connector 4 0 to 4 0 15 WN NOTE Double click on a table row to highlight corresponding elements Figure 6 8 Materials Report Maximum GPR or Worst Fault Condition Close Study Case Training Guide Power System Maximum GPR at Node Faults Considered Maximum Distance From GND_N ae as To Neutral Miles To Ground Compute 0 000 9 Both set to zero to consider all faults Worst Fault Condition Circuit Fault On Circuit 115 kV Line to Bus 30 1 Fault Type Line to Neutral Fault Fault Location 1 31 miles from bus SUB30 MaxGPR kv 22935 X R Ratio at Fault Location 82584 Phases Magnitude kA Phase deg FAULTBUS A 10 4298 107 0127 Fault Current ET 0 00 01 Figure 6 9 Worst Fault Conditions for Enhanced System Page 76 WinIGS Training Guide eS SS e Fy y ma Sa Se eS Figure 6 10 Touch Voltage Surface Plot for Enhanced System WinIGS Training Guide Page 77 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 A Grid Spacing 1000 0 ft L lA Moser lis Equi Touch Voltage Plot with respect to MAIN GND GND N gt Vperm 614 6 V Vmax 527 2 V Margin 16 58 B
75. EE Maximum Current kA Crest Value kA Sky Grid Size of Striking Distance 5 0 Isokeraunic Level 30 000 Map Maximum Sky Grid Size meters 5 000 Measured Data Minimum Stroke Current kA 5 000 Equal Current Steps of Current Striking Distance Steps 20 Equal Stroke Distance Steps Figure A4 5 Lightning Shielding Analysis Parameter Form a 1 TW I ELA ANTER HY 1 22i amg L 1 Br m E g f D 4 8 1 1 1 1 151 150 130 1 3 2 2 154549 19010909151 9 41 19 9 1 1 5 1 1 5 5 5 15 1 1 11 575 7 32 Figure A4 6 Grounding Window Display During Lightning Shielding Analysis 3D View Page 102 WinIGS Training Guide Figure A4 7 Grounding Window Display During Lightning Shielding Analysis Z Y Side View Once the LSA computations are completed a number of statistical reports can be generated The report generation process is demonstrated with two examples a LSA report for the phase conductors and b LSA report for the control house Lay aT To generate the phase conductors LSA report click on the button to activate the layer selection mode In this mode selection of any object results in automatic selection of all objects belonging to the same layer Click on any phase wire it is easiest to accomplish this in 3 D viewing mode All phase wires should now be highlighted drawn in red color as illustrated in Figure A4 8 Finally click on the button to view the phas
76. Electrical Equipment Shield Wires Bus Supports Lightning Poles ono Oo WO amp C P3 ENSEM UE EM m m m m m m m m m m m uj LE E E NE NE Neun I NL D m m m m m m m m m m m uj Figure A4 3 Layer Definition in Example System IGS AGUIDE CH12 Overhead Conductor Parameters Civil MIT Accept Line Phase Conductor Cancel segment Coordinates feet Conductor Specifications X feet Y feet Z feet Type ACSR 1 177 124 178 039 60 112 l 2 6 162 178 039 60 112 Size DRAKE 3 188 749 178 039 60 112 Group Layer Line Phase Conductors Flexible Sagg Factor 3 000 o Insulator Length 0 000 feet Add Vertex Remove Vertex Shield Wire 60 112 _ SetAllZ Coordinates SE aS OUO represent Figure A4 4 Phase Wire Layer Setting Example Page 100 WinIGS Training Guide A4 1 Electro Geometric Method To perform the Lightning Shielding Analysis LSA close the grounding viewing window and select the TOOLS mode Select the substation grounding system by clicking on the grounding system symbol single left mouse button click Next click on the Lightning Shielding button This action reopens the grounding system CAD window in LSA mode Note that in this mode the grounding system cannot be modified Note also that a new vertical toolbar appears along the left side of the program main frame A subset of the toolbar buttons is illustra
77. Insulation Material XLPE Outside Diameter 1 15 Insulation Shield none Material SEM r none Outside Diameter 12 Concentric Neutral Material COPPER Thickness 0 100 0 400 100 Number of Wies 28 28 None Tape Wires Wire Size 346 Jacket None Material nsulating c Semiconducting Diameter 1 4 All dimensions in inches Figure A1 5 Cable Wizard Window Page 82 WinIGS Training Guide WinlGs Company XYZ EXAMPLE o a 7 File Edit View Insert Window Help S x Tools Analysis Reports W Conductor Library Cable Library Tower Library AN Fuse Library Mat Lib Section Lib x 0 974 y 0 211 r 0 997 Name EXAMPLE Manufacturer Company XYZ Electrical Parameters Voltage 15 000 kV Ampacity in Duct 300 A Ampacity Buried 400 A Capacitance 0 3400 uF mile Inductance 0 3589 mH mile Mechanical Parameters Min Bending Radius 32 808 feet Weight 1 000 lb ft Conductor Parameters Number of Phases 1 Area 211 6 KCM Number of Strands 19 Diameter 0 528 inches Resistance 0 259 Ohms mile Material COPPER Insulation Parameters Diameter 1 150 inches Permitivity 2 800 Material XLPE Neutral Parameters Area 72 3 KCM Diameter 1 251 inches Resistance 0 758 Ohms mile Material COPPER Number of Strands 28 Jacket Parameters Diameter 1 400 inches Overall Diameter 1 400 inches Permitivity 4 000 Conductivity 0 000 Mhos meter
78. Isolated Grounding System Example Example Grounding System Soil Resistivity Model Exp Value Tolerance Upper Soil Resistivity 2385 6641 Ohm Meters Lower Soil Resistivity 109 6 394 Ohm Meters Upper Layer Thickness 253 t 431 Feet At Confidence Level 90 0 Results are valid to depth of 150 0 Feet Upper Soil Resistivity Lower Soil Resistivity Upper Layer Thickness 100 100 100 10 10 10 z z D 1 1 1 100m l i 4 i 100m l l i i 100m 4 i i 000 200 400 600 800 100 000 200 400 600 800 100 000 200 400 600 800 100 Conf Level Conf Level Conf Level Conf Emot Cont Emot Cont X Emor Figure 1 16 Wenner Method Soil Parameter Report Page 124 WinIGS Training Guide a lolx Copy Print Help Wenner Method Field Data Cancel Accept Isolated Grounding System Example Isolated Grounding System Example System Example Print Copy Import Export Example Grounding System Default Probe Spacing Resistance Apparent Resistivity in Feet a in i in Ohms V I Ohm Meters 22215 224 07 210 66 Dynamic Model Fit Report 10630 T Ee 3 3001 189 60 Corrected Measurement N 9 2 180 98 Model 7 pf 8 4500 3000 1900 16374 E w 9 5000 30000 1700 16278 160 87 g Hi 09 9 36900 0 50000 s 153 21 E 15321 F D 16 z 100m 0 00 20 0 40 0 60 0 80 0 100 D
79. M SUB20 SUB40 xs BUS40 Figure 3 8 Network View after Transmission Lines and Equivalent Sources are Created We are now ready to enter the model components representing the substation under study These include the substation breakers the autotransformer and the grounding system We will use connector elements to represent the substation breakers Use the toolbar button command nsert Connector to open the connector selection window WinIGS Training Guide Page 19 illustrated in Figure 3 9 Select the second entry titled Two Primary Bus Connector Model and click on he Accept button Connector element diagrams are entered in the same manner as transmission lines or other series elements Specifically left clicks add points along the connector path and a right click terminates the process Note that after the entry process 1s terminated you can still add and remove diagram points referred to as vertices using the toolbar buttons a Eam Add Vertex Short Cut Key F4 and Remove Vertex Short Cut Key Delete Note that the desired vertex to be removed must be selected before deleting it oa kakade Copy Frint Help Select Device Cancel Accept Code Description 191 Two Node Connector Model Two Primary Bus Connector Model 193 Two Secondary Bus Connector Model 195 Two DC Bus Connector Model Figure 3 9 Connector Selection Window Use ten of these elements to represent the breaker
80. Next close the Transmission Line Cross Section form and the Mutual Zero Sequence Parameters form by clicking on the corresponding Close buttons and click on the Generalized Pi Equivalent button of the Transmission Line Parameters Selection form see Figure 9 2 This action opens the Generalized Pi Equivalent form which is illustrated 1n Figure 9 7 This form displays the exact series or the exact shunt admittance matrix of the selected transmission line element Radio buttons allow the selection of either the series admittance matrix or the shunt admittance matrix as well as the display format rectangular or polar coordinates Note that when a single element of the matrix is selected by left mouse click the corresponding conductors are annotated in red text in the cross section diagram For example in Figure 9 7 phase conductors C1 and A2 are in red since the corresponding mutual impedance matrix element has been selected WinIGS Training Guide Page 199 Page 200 A1 B1 B2 C1 C2 N1 N2 N2 Generalized Pi Equivalent Transmission Line Parameters Close lt qW 70 0 feet M Display Selection Series Admittance Matrix Mhos Shunt Admittance Matrix micro Mhos 120 0 feet Real Imaginary Rectangular Magnitude OO MOO OQ Polar A1 A2 B1 0 01412 40 1039 0 0004434 3j0 01169 0 004790 30 02950 0 0004434 3j0 01169 0 01485 j0 1075 7040007136 30 01219 0 004790 j0 02950
81. RCEI to SUBI and SOURCE2 to SUBI feeding the Yellow Jacket distribution substation The substation consists of a transformer a grounding system a circuit breaker SUB3 to SUB2 and a connector which bonds the neutrals at the two sides of the transformer SUBI to SUB2 A distribution line SUB2 to LOAD1 is fed by the substation and is terminated by a single phase load and a load grounding at LOADI You can inspect the parameters of the example system components and make any desired changes by double clicking of the component icons Once the inspections and modifications are completed save the study case and proceed to the analysis section Page 158 WinIGS Training Guide B5 2 Analysis It is recommended that a base case analysis is performed first in order to verify that the system model is consistent Click on the Analysis button and select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis is completed a pop up window appears indicating the completion of the analysis Click on the Close button to close this window and then click on the Reports button to enter into the report viewing mode Select the Graphical I O mode and double click on all system components to view the voltage and current reports The results should consistent with normal system operation Specifically voltages should be nearly balanced Phase voltage magnitudes should be near nominal values
82. V Bus Phase Conductors Conductor Ground 230 0 4 00 230 kV Bus Phase Conductors Conductor 2m 115 0 5 00 115 kV Transmission Line Phase Conductc Conductor 2m 230 0 6 00 230 kV Transmission Line Phase Conductc New Edit Delete STOP Analysis Report Sort Figure A2 8 Setup Window Showing Selected Clearance Analysis Layers Page 94 WinIGS Training Guide Once the desired layers for clearance analysis have been selected click on the Analysis button of the Clearance Analysis Setup widow to perform the clearance analysis When the clearance analysis is completed the number of identified violations if any 1s listed at the bottom of the Clearance Analysis Setup widow The clearance violations are reported graphically as symbols overlaid over the model view window as illustrated in Figures A2 10 and A2 11 Each clearance symbol consists of a red line segment indication the violating clearance distance and a flag indicating the clearance violation number This number is also the order number with which clearance violations are listed on the clearance violation tabular report Note that clicking on the red line of the clearance violation symbol highlights the corresponding line in the tabular clearance violation report Click on the Report button of the clearance analysis setup window to open the report window shown in Figure A2 12 This window contains clearance violation table which lists the violation locations the violation
83. a systematic process of grounding enhancements followed by analysis and repeat this process as necessary for meeting safety requirements B6 1 Inspection of System Data In order to run this example execute the program WinIGS and open the study case titled IGS_AGUIDE_CH06 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 6 1 is displayed Note that the network model includes detailed models of the transmission lines which are directly connected to the substation The power system beyond the remote ends of these lines 1s represented by equivalent circuits and equivalent sources The parameters of an equivalent circuit model are illustrated in Figure 6 2 The circuit sequence parameters are entered in either in Ohms per unit or in percent In a typical utility organization the information needed to define network equivalents can be obtained from the protective relaying group A 3 D view of the substation grounding system is illustrated in Figure 6 2 It consists of a 5 x 7 mesh ground mat four ground rods and a metallic fence The configuration of major equipment transformers switchgear line towers control house 1s also shown You are encouraged to inspect the parameters of the remaining example system components and make any desired changes by double clicking of the component icon
84. age occurs near the upper right corner of the substation grounding system location is indicated by a sign The actual maximum touch voltage value is 1334 Volts while the maximum allowable touch voltage is 732 Volts WinIGS Training Guide Page 187 FEN ON PONENS S 09 6 s Y Grid S 100 0 ft ModelA i X Equi T ouch Voltage Plot A Vperm 732 V Vmax 1337 8 V A PS e a S B ee Cy 185 9 V 9j 2301 1 V x ES e 7 531 4 V i AN S S 646 6 V P CAN NN 761 8 V 2 ZANAN 8770v P COIN N f HZ N N 992 2 V SS X 1107 4 V NN NNI 1222 6 V N SS NS SS G Be SQ ING C YRS SMS d NWY SN i NN Y NN SS i D WN D ED Distribution substation grounding system Scale fee e cS Saas sss 0 70 140 210 C Advanced Grounding Concepts WinlGS 1 2 3 4 5 6 Figure 7 9 Touch Voltage Equipotential Plot for Worst Fault Conditions Next click on the 3D Plot button of the main toolbar and then click on the adi button to display the maximum allowable touch voltage plane see Figure 5 13 Note that the actual touch voltage represented by the blue curved surface violates the maximum allowable touch voltage limit represented by the horizontal red plane in many locations Note however that the station yard contains large areas with out any equipment to expose personnel to touch voltages In general it is neces
85. agram Report Selector form closes the neutral current and voltage is displayed on the system single line diagram as illustrated in Figure 4 4 Observe that the neutral voltage is elevated to 3 6 kV at the fault location to 687 volts at BUS 60 468 Volts at BUSSO etc Equiv Source Substation In 117 0 mA Figure 4 4 Single Line Diagram with Neural Voltage and Current Reports While in reports mode you are encouraged to examine the voltage and current reports of all system components First select the desired report type and then double clicking on any desired device to view the associated report The GPR and Fault Current Versus Fault Location function generates plots of GPR and fault current along any selected circuit for faults occurring on this circuit as a function of the fault location To use this function return to the Analysis environment select the GPR and Fault Current Versus Fault Location mode select the desired circuit by clicking on it and click on the Run button This action opens the report form illustrated in Figure 4 5 Click on the Update button of the report form to perform the analysis When the analysis is completed the traces of the GPR red trace and the Fault Current blue trace appear as illustrated in Figure 4 5 Page 154 WinIGS Training Guide Copy Print Help GPR and Fault Current Versus Fault Location 20 GPR Fault Current 3 00 S x w 2 00 a o 1 00 0 00
86. al values neutral voltages should be low and current magnitudes consistent with the system load For example Figure 3 3 shows the voltages and currents at the substation transformer terminals after base case solution was computed jet Copy Print Help Device RENE V I Report Return Short Circuit Analysis Example System TM Power Transformer 115kV 12kV 20MVA 66 41 kV 0 05D 6 903 kV 31 13D oo a O 22 81 A 8 41D 212 7 A 142 63D 6 906 kV 151 14D 4t O 66 41 kV 120 06D 1 2 213 6 A 22 59D 22 77 A 128 56D A x sje aad Ut a 212 2 A 97 32D 66 40 kV 119 95D 1 373 V 167 53D e m 22 74 A 111 60D 1 312 A 148 41D Ploss 104 7 kW Figure 3 2 Base Case Solution Voltage and Current Report The next step is to perform a short circuit analysis study For this purpose return to the Analysis mode select the Fault Analysis function and click on the Run button This action opens the Fault Analysis parameter form illustrated in Figure 3 3 Note that this form allows selection of fault location fault type and the faulted phases WinIGS Training Guide Page 141 Page 142 T eo Copy Print Help Fault Definition MEPE ae Cancel Execute Fault at a Bus rx Fault Type C Three Phase Fault Faulted Bus BUS30 C Line to Line to Neutral Line to Line to Ground c Fault on a Circuit Line to Neutral Faul
87. aphical I O mode and double click on the transformer of the wind turbine system one to display the transformer terminal voltages and currents see Figure 13 4 Note the grounding system voltage is 0 048 Volts while the electric current in the neutral is 64 65 Amperes The operating conditions in any other part of the system can be viewed by simply double clicking on any of the devices of the system WinIGS Training Guide Page 219 Device Graphical V I Report Farr Return Case Example 14 Wind Farm System Four Turbine 1 5 MVA Generator Syst PETES 1 75 MVA 34 5kV 575V Transformer 328 0 V 77 01D 19 75 kV 48 51D 13 18 A 147 14D 775 6 A 65 26D 327 7 V 163 12D 19 75 kV 168 50D 1 I s 2 827 2 A 175 84D 13 22 A 25 07D A Y 327 9 V 42 99D 767 5 A 55 28D 19 76 kV 71 48D 48 38 mV 134 67D 12 79 A 94 05D 64 65 A 12 08D Figure 13 4 Transformer Terminal Voltages and Currents WT One B13 3 Analysis Maximum Ground Potential Rise Click on the Analysis button and select the Maximum Ground Potential Rise analysis mode from the pull down list default mode and select the Maximum GPR at Node to be WTUI TWR N using the pull down menu The user interface form appears in Figure 13 5 Page 220 WinIGS Training Guide Maximum GPR or Worst Fault Condition Study Case Example 14 Wind Farm System Four Turbine 1 5 MVA C Maximum GPR at Node Faults Considered Maximum Di
88. ard versions which were shown to be less accurate They are included in this tool for compatibility with studies performed based on the older standards Page 56 WinIGS Training Guide Reduction Factor IEEE Std80 2000 Edition Update Close Standard IEEE Std80 1986 Ref 1 see Help IEEE Std80 2000 Native Soil Upper Layer Resistivity 243 1 Layer Resistivity 2000 0 Layer Thickness m 0 1000 k Factor 0 7827 0 00 Reduction Factor 0 00 0 05000 0 1000 0 1500 0 2000 02500 0 7244 Layer Thickness meters Reduction Factor Cs Figure 5 11 Surface Material Reduction Factor Dialog Window Allowable Touch and Step Voltages Button This button opens the safety criteria computation window illustrated in Figure 5 12 The safety criteria consist of the permissible values of touch and step voltages as well as the metal to metal permissible voltage These values are computed using the following data Electric Shock Duration Soil Resistivity Model Insulating Layer Thickness and Resistivity X R Ratio at fault location Standard Selection Options IEEE or IEC Note that the only input data to be set in this window are the Standard Selection Options and the Electric Shock Duration The Electric Shock Duration is usually determined from the protective relaying settings namely the fault clearing time Typical values for primary fault clearing times are given in Table 5 1 However it
89. ars indicating the location and type of the worst fault as well as the GPR X R ratio and the fault current corresponding to the worst fault conditions see Figure 5 2 Note that the worst fault for this system is a line to ground fault along the transmission line to bus at a distance of 1 31 miles from the substation The fault current is 10 43 kA and the ground potential rise at the substation 1s 2342 Volts The X R ratio at the fault location is 3 26 This value is automatically used to compute the Decrement Factor which is used to adjust the permissible touch and step voltages taking into account the fault current DC offset Click on the close button to close the dialog window We are now ready to switch to Reports Mode to examine the system performance under worst fault conditions Click on the Reports button to switch to Reports Mode See Figure 5 3 Note that under Reports Mode a number of radio buttons appear under the mode selection buttons which determine the type of report obtained when double clicking on any of the single line diagram elements The default selection is Graphical I O which provides reports of voltages and currents at the terminals of the selected device Page 50 WinIGS Training Guide Maximum GPR or Worst Fault Condition a Close Study Case Isolated Grounding System Example Maximum GPR at Node Faults Considered Maximum Distance From T GNDN EU O To Neutral De To Ground 0
90. ated upper left side of ground view window see Figure 5 14 to compute and display the equipotential plot The equipotential plots are lines of equal voltage which are color coded according to voltage level An automatically generated legend defines the color coding scheme The maximum voltage location is indicated by a black cross while the corresponding maximum value is indicated in the summary legend 750 Volts in the example of Figure 5 14 Note that the equipotential plot summary legend also lists the permissible voltage 614 6 V in this example If the maximum value is larger than the permissible as in this example the grounding system does not meet the standard requirements Page 62 WinIGS Training Guide File Edit Select View Insert Transformations Tools Window Help H c Equipotential Plots Edit Analysis Reports Tools Fr 155 92 y 232 32 ft AWin 12 13 Undo 1 do Update Return 3D Plot STOP C Earth Voltage Touch Voltage C StepVoltage Conductor Voltage 1 k 5 6 8 9 10 11 14 WinIGS Substatiion X Grounding System Case IGS TGUIDE 01 m S LO a a x amp Spacing 1000 0 ft A Pquency 60 00 Hz 8 Gn D z Equi Touch Voltage Plot with respect to MAIN GND GND_N ial Vperm 614 6 V Vmax 749 8 V Margin 18 02 GND_N MAIN GND Substation X WinlGS Training Ex ampie August 26 2014 REV 1 0 Advan
91. be edited by left double clicking on the conductor images WinIGS Training Guide Page 117 Grid Spacing 50 0 ft Model A Biquadratic Node Indexing Discretization with Sparsity GRSYS N MAIN GND b Example Grounding System Scale feet August 22 2002 IGS AGUIDE CH01A 0 cle 60 C Advanced Grounding Concepts WinIGS 1 z 3 4 5 6 Grid Spacing 50 0 ft Model A Biquadratic Node Indexing Discretization with Sparsity Example Grounding System August 22 2002 IGS AGUIDE CH01A C Advanced Grounding Concepts WinlGS 1 2 3 4 D 6 Figure 1 8 Grounding system Perspective View Page 118 WinIGS Training Guide Figure 1 9 Grounding system Rendered Perspective View For example Figure 1 10 illustrates the parameter form of a ground rod Note that the ground rod editable parameters include The x and y coordinates of the ground rod location in feet The depth below the earth surface of the ground rod top end in feet The ground rod length in feet The ground rod type and size The group name The layer name It is important to understand the significance of the Group Name parameter All conductors which are assigned the same group name are assumed to be electrically connected See the WinIGS users manual for more information on this topic Similarly Figure 1 11 illustrates the parameter form of a polygonal ground conductor WinIGS Training Guide Page 119 E loxi Accept Sing
92. bjective of these examples is to familiarize the user with the WinIGS user interface the input of the required data that define a study case system and the various analysis reports generated by the WinIGS program The user is encouraged to experiment with these examples by modifying the system data as well as the analysis parameters executing various analysis functions perform parametric studies and studying the analysis reports The applications guide contains 15 Appendices Each appendix treats a specific example A brief description of each Appendix is provided below Appendix Bl presents an example of an isolated grounding system analysis This example illustrates the computation of the characteristics of a grounding system such as the ground impedance and the touch voltage distribution for a given ground potential rise This approach is simplified in the sense that the effects of the power system network to which the grounding system is connected are neglected The analysis is performed by injecting an electric current into the grounding system It is tacitly implied that the user knows how much current is injected into the grounding system for example it is assumed that the user has performed and independent calculations for the split factor and computed the portion of the fault current that goes to the ground This approach is not recommended The example is simply provided for familiarizing the user with the grounding system analysis It
93. button to estimate the soil model parameters Note that during the analysis the resistance versus probe spacing trace computed from the soil model 1s superimposed on the plot of the corresponding measured values see Figure 1 15 This curve shifts as the soil model is adjusted to obtain the best fit to the measured data When the analysis process is completed the results are displayed in a pop up form illustrated in Figure 1 16 Next click on the Close button of the Model Fit Report and mark the 7 and 11 points as bad data Mark Unmark button then click on the Process button to repeat the data analysis The analysis results after removing the T and 11 points are illustrated in Figures 1 17 and 1 18 Note that the tolerance of the soil parameters are significantly reduced after the two bad data are marked The estimated soil model parameters are automatically saved in the study case data files Thus the above procedure does not have to be repeated every time this study case is opened You can inspect or manually modify the stored soil model parameters by selecting the User Specified Soil Model option in the Soil Resistivity Data Interpretation Form illustrated in Figure 1 13 and then clicking on the Edit Process button This action opens the User Specified Soil Model form which is illustrated in Figure 1 19 Click on the Accept button to close this form as well as the Soil Resistivity Data Interpretation Form and proceed to the system analys
94. ced Grounding Concepts WinlGS 70 105 1 2 3 4 5 6 8 9 10 11 107 1 4 mM For Help press F1 Figure 5 15 Safety Assessment Mode One simple approach to enhance the grounding system performance is to add additional eround conductors at the locations where the touch voltage exceeds the permissible value The touch voltage values at specific locations can be also directly examined by moving the mouse pointer at any location within the plot frame see Figure 5 15 WinIGS Training Guide Page 63 Touch Voltage at Mouse Location rey WinIGS Grounding System Geometric Model Case IGS TGUIDE 01 File Edit Select View Insert Transformations Tools Window Help P lt Equipotential Plots Edit 39 24 y 206 45 ft Redo Retun 2D Plot STOP Figure 5 16 Touch Voltage at Mouse Pointer Location Since distinguishing small color variations may be difficult it may be helpful to annotate the equipotential contour lines with numeric values as illustrated in Figure 5 16 The equipotential scale element can be used for this purpose The procedure for using this tool is described next Fr WiniGs Grounding System Geometric Model Case IGS TGUIDE 01 E Eie Edit Select View Insert Transformations Tools Window Help gt EETTZTLINN 2 quipotential Plots Edi Analysis Reports Tools NEN 3114 46 ye 209 15 It Touch Voltage 7115 V Ses r i boerapP
95. ceive the various components of the model as illustrated in Figure 4 2 Note that layer 7 has been named Drawing as itis intended to receive the provided site foundation drawing Make sure that the 7 row radio button in the column titled Act is activated This setting sets the editor to place any new objects created including an image to the es layer Next click on the Accept button to close the layers window Copy Print Help Ground System Editor Layers Cancel Accept 7 _ __ Act Model View Edit Color Dash Pagetof22 00 O co Oo c RR WO WM _ gt xa lt O A s M A m A 3 e I XI I S SI S XI S X X ll v EER u Ground Conductors EE m Foundations aa 4 a lt l Buildings x x Equipment a lt l a lt l Drawing TT Figure 4 2 Layer Options Window To insert a background image object click on the toolbar button or the insert reference object command opening the reference object selection window shown in Figure 4 3 Select the sixth row titled Picture JPG PNG BMP TIF then click on the Insert button WinIGS Training Guide Page 31 E sce t fe Copy Print Help Double Click on Element to be Inserted Node Interface Element Smart Ground Multimeter Position Annotation Text Reference Point Polygonal Line Picture JPG PNG BMP TIF Dimension Line E yg A Group MAIN GND Cond
96. click on the source icon to edit its parameters The source parameter window is illustrated in Figure 3 7 The source parameters include Source voltage Phase Sequence Positive Negative Zero The source impedance in sequence parameter form The power and voltage bases You can enter the sequence components of the source impedance either in per unit or in ohms Note that if you enter the parameters in ohms you must click on the Update PU button to automatically update the PU source impedance fields Conversely if you enter the parameters in PU you must click on the Update Ohms button to automatically update the source impedance fields in Ohms Similarly the source voltage is entered in both L N and L L values Use the corresponding Update L N or Update L L buttons to automatically update the alternate fields For this specific example we are provided the source voltage and short circuit capacity in GVA instead of the source impedance We can realize a source with a given GVA value by setting all reactive impedance components to 1 0 PU all resistive impedance components to 0 0 PU setting the MVA Base field to the desired short circuit capacity and then clicking on the Update Ohms button to automatically compute the appropriate WinIGS Training Guide Page 17 impedance in ohms For example the values shown in Figure 3 7 are for the 1 35 GVA source located at BUS 10 x ere es Copy Print Help Three Phase Source Accept Equiva
97. d the 3 additional conductor layers with appropriate clearance analysis parameters shown in Figure A2 8 WinlGs Clearance Analysis Example Case IGS TGUIDE 03 File Edit Select View Insert Transformations Window Help J UBNEETITEN 077 M Edit Mode Modeling Options Hepa Undo Redo et as 3 332 45 y 464 30 ft Soi Parameters Ier Iz 1 2 3 Maximum Conductor Current 8 SS poen Grid Spacing 100 0 ft Conductor Selection a Frequency 60 00 Hz Bill of Materials mulum Model A Ground Component List noh 8 Clearance Layer Setup Ira zl mee Copy Print Help ud J B Check Electrode Consistency SEEEN View Electrode Segescuation A aaa Clearance Analysis Setup Cancel k a 8 me a Mo SIE AUT ri Type Ground Voltage Minimum Layer Title EES E GPS Coordinates a m ui Check kV Distance ft LSA Options m eae 17 ET lim Pinti 3624 e ae LSA Analysis LSA Tabular Report X Em m emi m LSA Graphical Report HA Ap Clearance Analysis Mechanical Analysis Parameters z Mechanical Excitation Parameters TEx why Mechanical System Matrix Topology 3 z z m Le Liv Mechanical Eigenvalue Analysis Bre Zz Mechanical Measurement Elements ws 4 4 gt TT IEEE 605 Wind and Ice TAM 2 Edit STOP A i R ala i g i nalysis eport Store SDA State or alla G Recall SDA State wt a Ss Delete Sort Clear Highlighted Electrodes E EM b Emm F
98. e 13 6 Maximum Ground Potential Rise Report for WT One Ground B13 3 1 Inspection of Results Click on the Close button to close this window and then click on the Reports button to enter into the report viewing mode Select the Graphical I O mode and double click on the transformer of the wind turbine system one to display the transformer terminal voltages and currents see Figure 13 4 Note the grounding system voltage at the transformer is 2 803 Volts while the electric current in the neutral is 90 78 Amperes Note that the transformer ground voltage 1s the same as the maximum ground potential rise at the base of the tower The conditions in any other part of the system can be viewed by simply double clicking on any of the devices of the system Page 222 WinIGS Training Guide Device Graphical V I Report yn Return Case Example 14 Wind Farm System Four Turbine 1 5 MVA Generator Syst POSTES 1 75 MVA 34 5kV 575V Transformer 2 972 kV 103 03D 3 044 kV 105 11D 27 14 A 90 54D 1 712 kA 97 64D 2 849 kV 109 37D DS EEUEN 2 1 162 kA 102 49D 775 7 A 55 86D 22 15 kV 74 44D 2 803 kV 105 49D 23 30 A 105 41D 90 78 A 61 27D asv Figure 13 7 Transformer Terminal Voltages and Currents During Worst Fault Conditions Another important output is the generated touch and step voltages near the tower To compute and view these voltages select the Grounding Reports mode and double click on the grounding system
99. e Displays Figure 3 4 Single Line Diagram Reports Selector Form WinIGS Training Guide Page 143 Ya 7058 kV Yb 51 90 kV Va 7032 kV Yc 6233 kV Vb 5625 kV Ila 1176 A 28 Ila 1176 A Va 4072kV 928 A 1b 1928 A Vb 7 296 kV Ic 1492 A Ve 6379 kV Custom er 1 Figure 3 5 Single Line Diagram Indicating bus voltages and current flows Phase B to neutral fault at BUS30 While in reports mode you are encouraged to examine the voltage and current reports of all system components First select the desired report type and then double clicking on any desired device to view the associated report Four such example reports are given in Figures 3 6 through 3 9 Specifically Figure 3 6 shows the Graphical I O report for the transmission line from BUSIO to BUS30 Note that phase B conductor of this line contributes 4 85 kA to the fault at BUS30 Recall that the total fault current is 14 1 kA Figure 3 7 shows the Graphical I O report for the transmission line from BUS30 to BUS20 Note that phase B conductor of this line contributes 4 44 kA to the fault at BUS30 Figure 3 8 shows the Graphical I O report for the distribution line from BUS40 to BUS60 Note that the unbalanced voltages at the customer site Va 4 1 kV Vbz7 5 and Vc 6 4 kV The nominal phase to ground voltage at the distribution line is 6 928 kV thus phase C has a 9 overvoltage You can also view the voltage and current distribution along any desired c
100. e Electrode Slant Ground Conductor PolyLine Ground Conductor Circular Ground Conductor Connector Pig Tail Horizontal Conductor in G E M Ground Rod in G E M Vertical Chemical Ground Rod Polygonal Chemical Ground Rod Cancel Insert Defaults 2 3 4 5 6 T 8 9 10 11 12 13 14 15 16 Layer Fences Group MAIN GND Conductor COPPER 4 0 Figure 4 8 Ground Electrode Selection Window Next we will insert a perimeter ground conductor around the site fence The perimeter conductor shall consist of 2 0 copper buried 1 5 feet at a distance of 3 5 feet outside the fence This is a good practice for reducing touch voltages occurring outside the fence i e improving the safety of persons that may be standing and touching the fence outside the substation WinIGS Training Guide Page 37 Enim Fence Post Array Parameters JA Accept Fence Post Arra Cancel Fence Post Coordinates feet Update Diagram X feet Y feet 1 100 000 131 000 2 88 000 131 000 B 88 000 11 000 4 180 000 11 000 5 180 000 229 000 6 157 000 229 000 7 157 000 42 000 8 220 000 21 000 9 220 000 83 000 Group MAIN GND Add Vertex Remove Vertex Layer Fences Conductor Specifications Burial Depth positive 2 500 P Type ALU PIPE Post Length 10 500 des ac az Distance Between Posts 49 000 Size 2INCH Figure 4 9 Fence Element Properties Window Click again on the toolbar butt
101. e conductor LSA report illustrated in Figure A4 9 Similarly you can view the LSA report for the control house by first selecting the control house as illustrated in Figure A4 10 and then clicking on the z button to view the report illustrated in Figure A4 11 WinIGS Training Guide Page 103 Page 104 1 Grid Spacing 100 0 ft Frequency 60 00 Hz Model A Distribution substation grounding system Single Line To Neutral Fault at BUSS 20 21 Figure A4 8 Selected Lightning Shielding Analysis Bus Phase Conductors Rigid Line Phase Conductors Flexible Isokeraunic Level 30 00 Current kA 5 00 9 58 15 11 21 47 28 57 36 36 44 77 53 78 63 36 73 47 84 09 95 20 106 79 118 83 131 32 144 24 157 58 171 33 185 47 200 00 Exposed Area m2 2502 3 1504 0 557 1 112 1 12 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Grounding Window Display with All Phase Conductors Close Expected Number of Strikes 0 000187 0 000456 0 000256 0 000059 0 000007 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 0 000000 Total Number of Expected Strikes 0 00096 Figure A4 9 Tabular LSA Report for Phase Wires WinIGS Training Guide Lightning Shielding Analysis Close Bus Phase Conductors Rigid Line Phase Conductors Flexible Isokeraunic Level 30 00 Expect
102. e nameplate data of such equipment is sufficient e Parameters of the transmission lines connected to the substation For overhead circuits collect construction specifications such as overall line length span length conductor sizes locations and average pole ground resistance For underground cables cable models can be constructed from typical manufacturers data stating sizes and materials of the cable parts center conductor shields insulation jacket etc e Parameters of equivalent sources representing the system beyond the transmission lines connected to the substation under study Equivalent source parameters are typically available from system wide network modeling software If such data are not available the equivalent source capacities can be found by trial and error while trying to match the fault current levels at the substation of interest e A scaled top view layout drawing showing the foundations of the equipment to be installed If the study is for an existing substation also obtain a grounding drawing showing the locations of the ground conductors e Soil resistivity data collected at or near the site The most often used method to collect soil resistivity data is the Wenner method also known as the four pin method Multiple measurements should be taken at various probe spacings so that a the parameters of a two layer soil model can be reliably estimated form the field data The procedure of creating an integrated system
103. e objects include group and layer attributes The group attribute affects only conductor objects They determine which conductor objects are grouped together forming a particular phase conductor or neutral of a cable All conductive objects with the same group number are automatically assigned a single node name when included in a cable model Therefore conductors that represent different phases or neutrals and shields that are not bonded together must have distinct group numbers Group numbers of components representing insulation jackets or insulation shields and conduits are ignored Copy Print Help Insert Cable Component select Component Conductor Cylinder Conductor Array Conductor Strap Figure A1 7 Cable Component Creation Dialog Conductor Conductor Conductor Array otrap Cylinder ee FO i o e E e e i e l E hr s M e e d br _ 9 Figure A1 8 Primitive Cable Component Shapes Page 84 WinIGS Training Guide Copy Print Help Conductor Parameters Type Material amp Size Conductor Material COPPER Neutral Shield zoll 4 0 roupi E aah iol Number of Strands 19 Group 1 Area kcm 211 60 Layer A Diameter 0 5280 Center i TM All dimensions in inches 0 0000 0 0000 Cancel Accept Copy Print Help y Cylinder Parameters Center NUUSD Material XLPE Accept Group Y 0 0000 Layer Cancel Type Dimensions Phase Conductor anes Disemete
104. e point Furthermore the plot surface is color coded using three colors indicating three voltage regions The voltage regions corresponding to the plot colors can Lie be user defined using the vertical toolbar button This button opens the dialog WinIGS Training Guide Page 65 window illustrated in Figure 5 19 Click on the Allowable touch button to automatically set the red color to represent locations where the touch voltage exceeds the permissible voltage 614 V in this example and the yellow color to represent locations where the touch voltage exceeds the half the permissible voltage 307 V in this example Note that the red peaks occurring over seven of the hills of the surface plot define the locations where ground conductors can be added to eliminate the touch voltage violations The procedure of grounding system enhancement and the revaluation of the enhanced grounding system performance is presented in the next two sections ae oe Hiei A ti Figure 5 19 3 D Rendered View with Touch Voltage Plot Surface Page 66 WinIGS Training Guide Copy Print Help Surface Plot Voltage Threshold and Colors Single Color Multi Color Close Max Voltage Thresholds Volts Min Voltage aes Allowable Touch Allowable Step ZO Figure 5 20 Selection of Plot Surface Colors and Voltage Thresholds WinIGS Training Guide Page 67 6 Grounding Design Enhancement amp Analysis In the previous sec
105. e power grid The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH14 The single line diagram of the example system is illustrated in Figure 14 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results Figure 14 1 Single Line Diagram of Example System IGS AGUIDE CH15 Page 226 WinIGS Training Guide Scale feet Figure 14 2 Grounding System of Exam
106. e that the presence of the delta winding contributes to the fault current and increases the GPR for faults occurring outside the substation On the other hand for local faults the presence of the delta tertiary reduces the GPR These phenomena can be easily demonstrated Page 52 WinIGS Training Guide using this model The reader is encouraged to try these cases by changing the delta tertiary to a Wye connected tertiary and repeating the fault analysis Case Training Guide Power System ails 115 kV Line to Bus 30 54 36 kV 4 06D 20 50 kV 30 40D BUS30 A SUB30 A 1 358 kA 70 73D 9 064 kA 73 27D 63 40 kV 118 02D 60 06 kV 115 94D BUS30 B SUB30 B 387 1 A 108 23D 398 0 A 70 40D 66 42 kV 116 65D 67 34 kV 112 87D BUS30 C SUB30 C 399 8 A 113 02D 401 3 A 69 25D 391 1 V 99 72D 2 342 kV 106 96D BUS30 N SUB30_N 95 72 A 123 15D 4 620 kA 117 81D 391 1 V 99 72D 2 342 kV 106 96D BUS30 N SUB30 N 95 98 A 122 99D 1 620 kA 117 81D 12 79 kV 71 16D 10 43 kA 107 04D 63 18 kV 120 43D 69 34 kV 117 39D 12 79 kV 71 16D 5 214 kA 72 96D 12 79 kV 71 16D 5 214 kA 72 96D ISV Figure 5 6 Graphical Voltage and Current Report of Faulted Transmission Line WinIGS Training Guide Page 53 Autotransformer Internal Report Ve Close 280 MVA 115 230 kV AutoTransformer 67 47 kV I 12 96 D 13 37 kA 107 08 D 2 342 kV 106 96 D XF 2_A C 2 265 kA 7
107. ed Strikes and Exposed Area vs Current Crest Value Expected Number of Strikes Exposed Area 0 0015 2250 a 2 F E oO 2 D 0 00 1500 m AEN Z D Ee o g S D i x i 0 0015 zi 0 0030 7 1 i i 0 00 0 00 40 00 80 00 120 0 160 0 200 0 Current kA Total Number of Expected Strikes 0 00096 Figure A4 9 Graphical LSA Report for Phase Conductors Figure A4 10 Grounding Window Display with Control House Selected WinIGS Training Guide Page 105 Page 106 eiaa Ea Hae BAV EL ey 4 heer Close Control Building Isokeraunic Level 30 00 Current kA Exposed Area m2 Expected Number of Strikes 2 00 901 1 0 000067 9 58 534 6 0 000162 15 11 174 8 0 000080 21 47 17 0 000009 26 9f 0 0 0 000000 36 36 0 0 0 000000 AA TT 0 0 0 000000 203 78 0 0 0 000000 63 36 0 0 0 000000 3 47 0 0 0 000000 64 09 0 0 0 000000 95 20 0 0 0 000000 106 79 0 0 0 000000 118 83 0 0 0 000000 131 32 0 0 0 000000 144 24 0 0 0 000000 157 38 0 0 0 000000 171 33 0 0 0 000000 185 47 0 0 0 000000 200 00 0 0 0 000000 Total Number of Expected Strikes 0 00032 Figure A4 11 LSA Report for Control House A4 2 Rolling Sphere Method To perform the Lightning Shielding Analysis using the rolling sphere method close the grounding viewing window and select the TOOLS mode Select the substation grounding system by clicking on the grounding system symbol single left mouse button click Next click on the Light
108. ees Device Icon Size 0 100 Through Variable Displays Color Real Power Total P Color Reactive Power Total iy a q BUS10 Color Current Magnitude Phase A i v a a Color Hide Bus Names Hide Series Device Icons Hide Shunt Devices Hide Shunt Device Displays Figure 2 6 Result Display Selection Dialog Click on the white entry fields labeled Bus Voltage Displays and or Through Variable Displays and select the quantities shown in Figure 2 6 then click on the Accept button Page 138 WinIGS Training Guide This closes the display selection dialog and the selected quantities are overlaid on the single line diagram as illustrated in Figure 2 7 P 70 98 kw Q 380 4 VAr la 3613 A P 164 0 kW P 70 98 kW D 9224 kVAr 121 2 Q 3804 VAr H530982 5 mA A y 1la 3 613A Bus4o a o gt OE Py SY y P 7 187 mW P 7 187 mW Y lt O Q 13 56 uVAr Q 13 56 uVAr umm LET AE ES Figure 2 7 Single Line Diagram with Overlaid Result Displays WinIGS Training Guide Page 139 Appendix B3 Short Circuit Analysis This section illustrates the short circuit analysis capability of the program WinIGS The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH03 The single line diagram of the example system 1s illustrated in Figure 3 1 Step by step instructions lead the user through opening the case data files
109. elete Measurement C Bad Measurements Equivalent Separation Distance feet Delete All Measurements Mark Unmark Unmark All Distance Dom Rn NM mE Probe Diameter 0 625 inches lt I ACES RESIS Model Corrected Default Probe Length 30 00 inches Po UpperRho 24375 Qm Model Data Fit Operating Frequency 72 00 Hz M Remove Induced Voltage 055 Lower Rho 146 95 Qm Cpl Cp CA Layer Depth 15 82 feet Computations Completed Se ensitivity 3 Layer Model Fit Soil Model STOP Process State Limits Objective 0 002363 Figure 1 17 Wenner Method Field Data Entry Form Bad Data Removed Copy Print Help Wenner Method Soil Parameters Case Name IGS AGUIDE CH01 Description Isolated Grounding System Example Example Grounding System Soil Resistivity Model Exp Value Tolerance Upper Soil Resistivity 2438 D 59 Ohm Meters Lower Soil Resistivity 146 9 2 8 Ohm Meters Upper Layer Thickness 158 09 Feet At Confidence Level 90 0 Results are valid to depth of 150 0 Feet Lower Soil Resistivity Upper Layer Thickness 100 100 10 10 10 z Li z 1 1 1 100m 4 i 1 100m d 100m l u i 000 200 400 600 800 100 000 200 400 600 800 100 000 200 400 600 800 100 Conf Level Conf Level Conf Level cont servos eont sSwc Cot Bmr Figure 1 18 Wenner Method Soil Parameter
110. ely To recreate these reports click on the Multimeter radio button located along the main program toolbar and then left double click on the transformer diagram Once the Multimeter window opens select the quantities of interest voltage and current radio buttons and the voltage and current terminal nodes Note that you can select monitored nodes individually by clicking on each node name field or use the Side 1 and Side 2 buttons to automatically set all node names Also note that the reported current positive direction is always into the selected device WinIGS Training Guide Page 149 Copy Print Help Device Terminal Multimeter Close Case Short Circuit Analysis Example System Device Power Transformer 115kV 12kV 20MVA Side 1 Side 2 3 Phase Power Voltage _ e L G Phase Quantities r Per Phase Power v Current L L C Symmetric Comp r Impedance Voltages Van 11 72 KV 9 608 Deg BUS30 A e a Vbn 77 26 kV 138 3 Deg ES Vcn 7 86 87 kV 133 4 Deg BUS30_ B s la 744 2 A 107 7 Deg e Ib 20 26 A 120 7 Deg BUS30_C Ic 730 9 A 71 13 Deg BUS30_N e s VN 3 Currents ff BUS30 A e ar BUS30 B o BUSS0C Figure 3 14 Transformer Primary Terminal Voltages and Currents during Fault between Transformer High and Low Voltage Phase A Terminals BUS30 A and BUS40 A Copy Prnt Help De
111. emme Blink Highlighted Electrodes Ime F Layer Group H Select Highlighted Electrodes De nth Tyne Delete Corrupted Elements SD si AutoGroup Development Use 8 Reserved Development Use Megh Electr Y Clearance Analysis Example Level Freeze 3D Substation Model feet March 19 2015 J j SR 180 270 Advanced Grounding Concepts WinlGS ae ae vqopI a T Copy Print Help Clearance Layer Parameters l Cancel OK Layer 115 kV Transmission Line Phase Conductors Excluded Objects Phase Conductors Type Nominal Voltage Clearance to Ground None Minimum Distance 5 00 feet c To Ground IEEE 1427 To 2m Above Ground Objects in excluded layers are not considered in cearance analysis Figure A2 6 Clearance Layer Parameters Dialog Window WinIGS Training Guide Page 93 E Advanced Grou ding or ots Copy Print Help Minimum Clearance vs BIL Cancel OK Nominal B L L GClearance L L Clearance Voltage kV kV feet feet 1 20 30 0 0 187 0 207 0 282 1 2 3 4 5 6 7 8 9 Table 3 from IEEE Guide 1427 Recommended minimum electrical clearances for air insulated substations when lightning impulse conditions govern Figure A2 7 Table of Minimum Clearance versus Nominal Voltage and Basic Insulation Level from IEEE Guide 1427 Gopymintm pm Clearance Analysis Setup Ground Voltage Minimum Check kV Distance ft Conductor Ground 115 0 3 00 115 k
112. enner Method Field Data Entry Form Page 122 WinIGS Training Guide Note that the entered data include e Probe Spacing Probe Length Resistance and Apparent Resistivity Table e Probe Diameter e Meter Operating Frequency In entering this data either the resistance or the apparent resistivity column data must be manually typed along with the corresponding probe length and spacing The update buttons can be used to automatically fill in the unfilled column Specifically if the resistance data are manually entered click on the right update button to automatically compute and fill in the apparent resistivity column Similarly if the apparent resistivity data are manually entered click on the right update button to automatically compute and fill in the resistance column Note that the probe length entered in the second column is the length of the probe in contact with soil 1 e not the entire length of the probe The form allows for different probe lengths for different probe spacings The form automatically displays the entered data in graphical form in the measured resistance versus probe separation plot By inspection of the plotted data you can identify possible bad data In this example the 7 and 11 points deviate significantly from the rest You can mark thus identified bad data to be excluded from the analysis by clicking on these data on the table and then clicking on the button Mark Unmark Next click on the Process
113. er of points along the longest dimension of the plot frame For example if the plot frame is a 50 by 100 rectangle setting the resolution to 200 will result in a grid point spacing of 0 5 feet Once the grid point voltages are computed a number of equipotential lines are drawn with either linearly or logarithmically spaced values option selected by the Linear Log radio buttons The Contours field sets the number of contours drawn for the linear distribution option while the Decades field sets the number of contours drawn for the logarithmic distribution option The Draw a Contour at field adds an additional contour using a thick orange line at a user specified voltage A common example where this feature is useful 1s to identify the zone of influence of a grounding system defined as the distance from the grounding system center beyond which the ground potential rise falls below 300 V Legend Controls These controls determine the style and font size for the legends generated with the equipotential plots Note that for polygonal plot frames the legends can be relocated using the mouse Once the equipotential frames are completed you can left click and drag the legend text at any desired location Generating Equipotential Plots Once the equipotential plot frame parameters have been adjusted as needed click on the radio button to select the desired quantity to be plotted for example Touch Voltage and then click on the Update button loc
114. es Delete Corrupted Elements BUS30 N ES MAIN GND 4 pl p Reserved Development Use e RENE Distribution substation grounding system Single Line To Neutral Fault at BUS30 AutoGroup Development Use ee Conductor Size Selection Figure A3 1 Conductor Selection Command WinIGS Training Guide Page 109 The conductor selection command opens the dialog window shown in Figure A3 2 Edit the input data fields as necessary specifically Fault Current Fault Duration Ambient Temperature Permissible Conductor Temperature Conductor Material Then click on the Update button to obtain the minimum conductor cross section area that will not melt for the selected conditions z Copy Print Help Conductor Size Selection Fault Current 30 0 KA Fault Duration 0500 seconds Ambient Temperature 400 Ge Permissible Conductor Temperature 4500 e Conductor Material Copper annealed soft drawn a 194 6 kemils 98 6 mm Next Standard Conductor Size 4 0 211 6 kcm Minimum Conductor Size Figure A3 2 Conductor Selection Dialog Window Page 110 WinIGS Training Guide Appendix B Applications Guide Appendix BO Overview This applications guide provides several application examples that illustrate the use of the program WinIGS For each application example the data files have been prepared and are available with the program WinIGS The o
115. esistance Voltage Current G N Node N i a ee Ohms Volts Amperes MAIN GND GRSYS N 1 0256 6666 33 6500 00 Rp 1 0256 Earth Current 6500 00 Fault Current 0 00 Split Factor N A Le Driving Point Resistance Definition C Equivalent Circuit Shunt Branch View Full Matrix Figure 1 21 Grounding System Resistance Report Next click on the Resistive Layer Effects button to open the reduction factor computation form illustrated in Figure 1 22 The reduction factor models the effect of a recessive layer typically crushed rock or gravel placed on top of the soil to improve safety The input parameters for the reduction factor computations are a the layer resistivity default value of 2000 0 ohm meters and the layer thickness default value of 0 1 meters Note that the native soil upper layer resistivity is also displayed 243 8 ohm meters since it is used in the reduction factor computation However it cannot be modified at this level It is automatically retrieved from the stored two layer soil model parameters Once the input data are entered click on the Update button to compute the reduction factor The result is displayed at the lower right end of this form 0 7244 in this example Next click on the Close button to close the reduction factor computation form and click on the Allowable Touch and Step Voltages button to open the Safety Criteria computation form illustrated in Figure 1 23 Thi
116. ethod Three Pin Method Smart Ground Multimeter Data Close Edit Process Figure 4 16 Soil Data Type Selection Window WinIGS Training Guide Page 45 Sec Copy Print Help Wenner Method Field Data Cancel Accept Isolated Grounding System Example Print Copy Import Export Grounding System Geometric Model Sort Default Update Update Probe Spacing a Probe Lensth L Resistance feet inches in Ohms V I 30 000 1160 7 8001 20 000 Dynamic Model Fit Report 25 000 a Sorrested Meapurement 40 000 mR 45 000 11 70 000 12 13 i a 16 s Delete Measurement Bad Measurements Delete All Measurements Mark Unmark Unmark All Um 20 00 40 00 60 00 80 00 100 0 Equivalent Separation Distance feet Probe Diameter 0 500 inches Algorithm Controls Default Probe Length 12 000 inches Distance Raw Meas No Correction Model Corrected t S Induced Voltage Correction C Real Part Only Operating Frequency 72 00 Hz C Real Reactive Model Data Fit Lower Rho 109 50 om V I Lead Separation 20 00 feet View Corrected Data C pl p2 A Layer Depth 25 22 ft Computations Completed Cpi Cp2 CA RS Objective 0 714417 Slayer ModelFit SoilModel STOP Process Sensitivity 0 CO I CV Wa BY Wo nj S2 trl S o IEIIEIEIE S Resistance Ohms dt Upper Rho 238 61 am F
117. g System and Major Structures The objective of this chapter is to demonstrate the usage of the WinIGS program in generation station grounding design Analysis of the example system in its present form indicates that it does not meet IEEE Std 80 safety requirements The user is directed to follow a modify analyze cycle leading to a safe grounding system B7 1 Inspection of System Data In order to run this example execute the program WinIGS and open the study case titled IGS_AGUIDE_CH07 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 7 1 is displayed You can inspect the parameters of the example system components and make any desired changes by double clicking of the component icons Once the inspections and modifications are completed save the study case and proceed to the analysis section B7 2 Analysis It is recommended that a base case analysis is performed first in order to verify that the system model is consistent Click on the Analysis button and select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis is completed a pop up window appears indicating the completion of the analysis Click on the Close button to close this window and then click on the Reports button to enter into the report viewing m
118. g on the bus SOURCE the diagram illustrated in Figure 1 2 appears This diagram shows that the source ground is connected to node SOURCE_N the source is connected to nodes SOURCE_A and SOURCE_N and the 1 0 ohm resistor is connected to the node SOURCE A The other terminal of the 1 ohm resistor is connected to the bus GRSYS and thus it does not appear in this diagram Bus Connections o x SOURCE N SOURCE A Source Ground single Phase Current Source 5 KA 1 Qhm Resistor Figure 1 2 Node Connections at Bus SOURCE Similarly the connectivity at bus GRSYS is obtained by double clicking on the bus GRSYS This action generates the diagram illustrated in Figure 1 3 This diagram shows that both the 1 0 ohm resistor and the grounding system are connected to the same node GRSYS_N Bus Connections n x Un Ui cr D Example Grounding System 1 Ohm Resistor Page 114 WinIGS Training Guide Figure 1 3 Node Connections at Bus GRSYS It is important to note that node names are assigned by the user Node names are edited via the device parameter forms You can open any device parameter form by left double clicking on the device symbols For example by double clicking on the source symbol the source parameter form is displayed which is illustrated in Figure 1 4 Observe the node name entry fields SOURCE_A and SOURCE_N These fields are user editable Single Phase Current Source 5 kA
119. g the Clearance Analysis command of the Tools pull down menu or using a vertical toolbar button illustrated in Figure A2 4 This command opens the Clearance Analysis Setup dialog window also shown in Figure A2 5 The Clearance Analysis Setup dialog window allows the user to specify which layers contain conductors to be checked for clearance violations A permissible minimum clearance distance is assigned to each conductor layer Additional layers can be defined for objects to be excluded from clearance checking These layers are referred to as Exclude layers The New Edit Delete and Sort buttons located at the bottom of the dialog window allow management of the user defined layers The layer creation process is described next Click on the New button to select a conductor layer and define the clearance analysis parameters The clearance layer parameter window opens which is illustrated in Figure A2 6 Click on the Layer field to select the desired layer titled 115 KV Transmission line conductors Set the nominal voltage field to 115 kV and set the minimum distance to 5 0 feet Select the To 2m above Ground radio button and click on the OK button Guidance for selection of minimum clearance distances are provided in the IEEE Standard 1427 For convenience the information from Table 3 of Standard 1427 1s displayed when the button IEEE 1427 is clicked as illustrated in Figure A2 7 WinIGS Training Guide Continue as described above to ad
120. ge 218 WinIGS Training Guide B13 1 Inspection of System Data Execute the program WinIGS and open the study case titled IGS_AGUIDE_CH13 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 13 1 is displayed The example system consists of a substation and two transmission lines connecting the substation to the power system The power system beyond the remote end of the two transmission lines is represented by two equivalent sources Two feeders originate at the substation One feeder is connected to a four turbine wind farm The feeder is partially overhead and partially underground Each wind turbine generator system is modeled in detail see Figures 13 2 and 13 3 It includes a representation of the tower the blades the generator the grounding of the tower the transformer and the circuit between the generator and the transformer B13 2 Analysis Steady State Operation Click on the Analysis button and select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis is completed a pop up window appears indicating the completion of the analysis B13 2 1 Inspection of Results Click on the Close button to close this window and then click on the Reports button to enter into the report viewing mode Select the Gr
121. ge File Apply OK File C WMstrDoc WinIGS Training_Guide gnd_drawing jpg Layer p Drawing Color Shift C Off 100 00 C Red E C Green 80 000 Blue M Transparent C Low Contrast Cropping r Crop Left 0 000 Right 0 000 Top 0 000 Bottom 0000 Clear Sitatatco K ean Td Rotation Angle 0 000 Deg 2 0 2 0 2 2 Reset to Zero M Hide Added Area Bilinear Auto Scaling Present Length 400 000 ft Actual Length 400 000 ft Match View Top C Z X C Z Y Rendering C Fast Color Halftone Color C Monochrome White BG Monochrome Black BG Aspect C Adjust Preserve Histogram Image Specs Image Size 1674 x 1665 pixels 24 Bits Per Pixel Pitch 5024 DIB 1 Trans 1 Indexed 0 Figure 4 4 Image File Properties Window Note that in Figure 4 5 b the reference segment is superimposed over a 400 foot dimensioning line It is recommended to zoom in near each end point so that the reference segment is accurately positioned to match the drawing dimension line Next left double click on the drawing image to open its parameter window one more time refer back to Figure 4 4 In the Auto Scaling group set the actual length field to 400 feet then click on the Match button The drawing image is now to scale WinIGS Training Guide Page 33 Page 34 Win
122. h column to automatically fill in the Apparent Resistivity data Set the Default Probe Length field to 12 000 inches length L in Figure 4 15 then click on the Default button located over the Probe Length column to automatically set all entries to 12 inches Next click on the Process button to initiate the data analysis After the analysis is completed the soil model parameters window opens displaying the results Note that the results include the expected values of the three soil model parameters upper and lower resistivities and upper layer thickness and the computed tolerance for each parameter at a user specified confidence level 90 by default The results also provide an estimate of the Validity Depth This value 150 feet for this case is the maximum depth to which the measurements are sensitive The soil resistivity beyond this depth cannot be estimated from the given measurement set Note that to increase the validity depth additional measurements are higher probe separations must be taken Click on Close button to close the results form Page 44 WinIGS Training Guide Note that once the analysis is completed the Wenner Field Data window displays a resistance versus probe separation plot see Figure 4 17 This plot shows the measurement data red dots and a green curve representing the estimated resistance computed using the 2 layer soil model A match between measured and estimated values indicates that the 2 layer soil mode
123. h is to compute the ground current by modeling the power system network along with the grounding system under study Examples that illustrate the WinIGS Training Guide Page 133 analysis of the integrated system grounding plus power system network model are given in subsequent sections Page 134 WinIGS Training Guide Appendix B2 Steady State Power Flow Analysis This section illustrates the power flow analysis capability of the program WinIGS The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS AGUIDE CH02 The single line diagram of the example system 1s illustrated in Figure 2 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results PV Bus snb 4 SEO 9 Me d 3 Phase Load 1 Phase Load Figure 2 1 Single Line Diagram of Example System IGS AGUIDE CH02 B2 1 Inspection of System Data The example system consists of two transmission lines two equivalent sources two distribution lines a substation model consisting of delta wye connected transformer and a grounding system You can inspect the parameters of the example system components and make any desired changes by double clicking of the component icons Once the inspections and modifications are completed save the study case and proceed to the analysis section B2 2 Analysis In order to perform the analysi
124. harmonic voltage and current propagation in a multiphase power system Appendix B12 provides an example for assessing the effectiveness of a cathodic protection system Appendix B13 provides an example of wind farm grounding system analysis Appendix B14 provides an example of PV plant grounding system analysis Page 112 WinIGS Training Guide Appendix B1 Isolated Grounding System Analysis This Appendix illustrates the analysis of an isolated grounding system using the WinIGS program The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS AGUIDE CHOI The single line diagram of the example system is illustrated in Figure 1 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results The system of Figure 1 1 can be used for design of a grounding system when the earth or grid current is known The earth or grid current is the fault current times the split factor It is important to note that the split factor depends on many parameters of the system around the grounding system under design and it can be any value between zero and 1 0 Resistor SOURCE GRSYS Source Source Ground Grounding System Figure 1 1 Single Line Diagram of Example System IGS_AGUIDE_CH01 B1 1 Inspection of System Data In order to run this example execute the progra
125. he fault location is 1 308 Next Close this form by clicking on the Close button and proceed to the results inspection section B7 3 Inspection of Results The worst fault analysis described in the previous section terminated with the system solution for the identified worst fault condition In this section we examine the grounding system performance under these conditions Click on the Reports mode button and select Graphical I O mode Left double click on the grounding system icon to view the grounding system voltage and current report This report is illustrated in Figure 7 5 Note that the ground current is 6 908 kA Since the total fault current is 12 58 kA the split factor for this system is 54 9 Page 184 WinIGS Training Guide Device Graphical VO Report Return Case Generation Substation Grounding System Design Device Distribution substation grounding system 3 650 kV 159 46D 6 921 kA 159 46D Remote Earth 6 921 kA 159 46D Program WinlGS Form FDR GDIO Figure 7 5 Grounding System Voltage and Current Report Next close the grounding system voltage and current report and select the Grounding Reports mode radio button Left double click on the grounding system icon to enter into the grounding system reports mode Click on the Grounding Resistance button to view the Grounding system resistance report This report 1s illustrated 1n Figure 7 6 Note that the reported resistance is 0 527 ohms
126. he grounding editor window is illustrated in Figure 3 1 showing the default ground system a rectangular ground mat You can delete the default ground mat element at this point since we will be creating a custom ground design from scratch Just select it by left clicking on its perimeter conductor and then press the delete key The default grounding system also contains an Interface Node shown below which establishes a connection between the grounding electrodes and the network model defined in the network editor Keep this element we will revisit the function of this element later DN MAIN GND Node Interface Element The grounding system editor provides a 3 D editing capability It always starts in top view mode but the user can switch to side view perspective view or rendered 3 D view using the toolbar buttons Top View Mode X Y z Z X Side View Mode Z Y Side View Mode Perspective View Mode TE Rendered 3 D View Mode WinIGS Training Guide Page 29 Note that insertion of new elements in the grounding system model are only allowed in top view mode However moving and reshaping elements can also be performed in side views and perspective view Most of the functions available in the ground editor can be performed using the two columns of buttons located on the left side of the view window For a complete description of the functions of all the ground editor buttons and commands please refer to the WinIGS User
127. ic Cap Saturable Core Transformer with Secondary Centertap Single Phase 1 3 4 5 6 T a 9 10 11 2 Figure 3 18 Multi terminal Element Selection Window WinIGS Training Guide Page 27 10 BUS20 Substation X BUS30 BUS40 Figure 3 19 Completed Network Model Note Annotation elements such as text and dashed dotted lines can be added as desired A m using the toolbar buttons and respectively Page 28 WinIGS Training Guide 4 Editing the Grounding Model The detailed physical structure of the grounding system under study is represented in the Grounding System Geometric Model element Double Clicking on this element opens a Ground Editor window which provides the following functions e Creating grounding structure model using ground electrode elements e Entering Soil resistivity field measurement data and performing resistivity measurement data analysis The analysis provides the parameters of a two layer soil model e Creating a 3D representation of civil structures and outdoor equipment for the purpose of performing lightning shielding analysis as well as structural dynamic analysis The first two of the above functions are demonstrated in this Section using the example system introduced in Section 2 using the information provided in Figure 2 2 and Table 2 1 To get started left double click on the Grounding System Geometric Model icon to open the grounding system editor T
128. ical toolbar Like Then click on the emi button located in the left vertical toolbar to display or modify the color mapping assignment You can alter the point of view using the mouse Specifically you can zoom using the mouse wheel pan with the right mouse button and rotate with the left mouse button Note that in regions where the blue curved surface is above the red plane the actual touch voltage exceeds the maximum allowable value Page 132 WinIGS Training Guide Figure 1 26 Touch Voltage Report 3 D Surface Plot B1 4 Discussion The presented isolated grounding system analysis procedure provides a quick and simple way to obtain fundamental characteristics of a grounding system such as the ground impedance and the touch voltage distribution for a given ground current This approach is simplified in the sense that the ground current magnitude is set to an arbitrary value It is customary to derive this current value from fault analysis studies However it 1s important to note that the current injected into the grounding system is a fraction of the full fault current Specifically when a fault occurs the fault current splits among all available paths and only a portion of the fault current is injected into the grounding system This means that if the current source in this example is set to the full fault current the ground potential rise of the grounding system and the touch voltage will be overestimated A better approac
129. ick on the Close button to close this window and then click on the Reports button to enter into the report viewing mode Select the Graphical I O mode and double click on the cathodic protection source to display the source terminal voltages and currents see Figure 12 4 Note that the grounding system voltage rises to 3 389 Volts DC when the cathodic protection source injects 80 Amperes while the cathodic protection sacrificial electrode voltage is 59 24 Volts Device Graphical VO Report Return Case Cathodic Protection Analysis Example Device Cathodic Protection Source 3 389 V 0 73D 80 00 A 180 00D 59 24 V 179 97D 80 00 A 0 00D Program WinlGS Form FDR GDIO Figure 12 4 Cathodic Protection Source Terminal Voltages and Currents Select the Grounding Reports mode and double click on the grounding system icon to open the grounding system report mode view Select Equipotentials and Safety Assesment and click update to view the soil voltage distribution around the cathodic protection sacrificial electrode see Figures 12 5 and 12 6 Page 214 WinIGS Training Guide Ly 1 2 3 4 5 6 Z 8 Grid Spacing 100 0 ft Model B Equi Earth Voltage Plot A yz252 V EN 2 3 V D NQATHPROT N 4 6 V eae 6 9 V B C D E Y Generating Plant N ue Grounding System SES AGC 3 2003 1001 0 N S C Advanced Grounding
130. iew the parameters of the other circuits of the selected element by clicking on the buttons a located at the top of the sequence parameter form Note that the selected circuit phases are annotated in red color in the line configuration diagram which 1s displayed at the bottom right side of the form You can also view the sequence equivalent networks by clicking on the Sequence Networks button located at the top of the transmission line parameters form The Sequence Networks report for the BUS10 to BUS30 transmission lien is illustrated in Figure 9 4 WinIGS Training Guide Page 195 EN Line Parameters Circuit Selection Sequence Networks Line Name Mutually Coupled Transmission lines Bus 20 to Bus 30 From Bus Name BUS30 Section Length miles 0 000 To Bus Name BUS 20 Line Length miles 10 000 Circuit CKT1 Operating Voltage kV 115 Section 0 of 0 Insulation Voltage kV 1135 Year Built N A Structure Name N A Phase Conductors Ground Conductors Type Size ACSR CANARY Type Size HS 5 16HS Phase Spacing ft 30 00 15 00 15 00 Number of Ground Cond 1 Conductors per Bundle Spacing ft N A Bundle Spacing inches N A Equivalent GMR ft x 1000 0 000365 Equivalent GMR ft 0 039303 Resistance Ohms mi 25 C 9 700000 Resistance Ohms mi 25 C 0 102200 Equivalent Diameter inches 0 221853 Equivalent Diameter inches 1 168230 Distance to Phase Cond ft
131. igure 10 2 Generalized Transmission Line Model Parameters Form Conductor Configuration Close 7 3 5 feet Ad B1 C1 N1 N2 38 0 feet Program WinlGS Form IGS 109B Figure 10 3 Conductor Configuration Report B10 2 Analysis Close all parameter forms and click on the Analysis button Select the Maximum Induced Transfer Voltage function and click on the Run button This action opens the Page 202 WinIGS Training Guide Maximum Induced Transfer Voltage analysis parameter form illustrated in Figure 10 4 Select the Port Definition nodes as indicated in this Figure and click on the Compute button Maximum Transfer Induced Voltage Study Case Induced Transferred Voltage Computations Port Definition Faults Considered From COMMCIR_N e puel To Ground To BUS60_N Both Fault Description Circuit Fault On Circuit Pe Fault Type PO Fault Location Pe Maximum Transfer Induced Voltage kV o X R Ratio at Fault Location oo Fault Current Magnitude kA Phase deg NENNEN Program WinlGS Form MAX VOLTAGE Figure 10 4 Maximum Induced Transfer Voltage Analysis Parameters B10 3 Inspection of Results Once the analysis is completed the Maximum Induced Transfer Voltage analysis parameter form reappears with a summary of the results as illustrated in Figure 10 5 Note that the results indicate that the maximum induced voltage to the communication circuit measured
132. igure 4 17 Wenner Method Data Entry amp Analysis Window Page 46 WinIGS Training Guide Copy Print Help Wenner Method Soil Parameters Close Case Name IGS_TGUIDE_01 Description Isolated Grounding System Example Grounding System Geometric Model Soil Resistivity Model Exp Value Tolerance _ Upper Soil Resistivity 238 6 t 66 3 Ohm Meters ya Lower Soil Resistivity 109 5 T 39 3 Ohm Meters Apper Layer Thickness 25 2 t 133 feet At Confidence Level 90 0 Results are valid to depth of 150 0 feet Upper Soil Resistivity Lower Soil Resistivity Upper Layer Thickness 100m l 100m 5 r l t x 100m t r l 0 00 20 00 40 00 60 00 80 00 100 0 0 00 20 00 40 00 60 00 80 00 100 0 0 00 20 00 40 00 60 00 380 00 100 0 Conf Level Conf Level Conf Level Conf Error Conf Error I Conf fo Error Figure 4 18 Wenner Method 2 Layer Soil Model Parameters Report WinIGS Training Guide Page 47 Copy Print Help Wenner Method Field Data Cancel Accept Isolated Grounding System Example Print Copy Import Export Grounding System Geometric Model Default Update Update Probe Lensth L inches 30 000 Dynamic Model Fit Report Raw Measurement Corrected Measurement Model O CO OV Ca I Wo Nj Hin w w ojo ajo i oo ojo px iun uw E lt 9 o o c S D e o c E Delete Measurement Bad Measu
133. ing towers or poles but do not include the grounding at the two line ends Edit the Ground Impedance Model parameters by left double clicking on it and set the ground resistance value to 25 ohms Page 70 WinIGS Training Guide Copy Print Help s y Model Conversion ES Mutually Coupled Multiphase Line Model l Convert Overhead Line Model to Multisection 3 Phase Transmission Line Model I Convert Geometric Ground Model to Ground Resistance Model r Remove Cable Grounding Set cable model span lenght equal to cable lenghth Cancel Convert Apply to Selected Devices Only Apply to All Devices NITET Copy Print Help Mutually Coupled Multiphase Lines Cancel Accept 2 Spans of 115 kV Line to Bus 10 Auto Title Select Tower Add Tower X Offset ft 75 00 View Configuration 4 Circuits Line Length Figure 6 4 Adding a Counterpoise Ground to The Mutually Coupled 0 16 miles WinIGS Training Guide 115 0 N A Copy Edit Name Span mi Gr R Gr X OpV kV FOW kV BIL kV AC kV TrPh TrSh 1 cCKM 008 250 00 N A Soil Resistivity ohm meters N A 100 0 NO Conductors Copy Edit Delete L FromNode ToNode Circuit Cond Size Sub Sep Gnd Xi ft Y ft 14 SUB10X_A SUB10A CKT1 ACSR FINCH 1 0 0000 NO 0 0000 55 5000 2 SUB10X_B SUB10 B CKTi ACSR FINCH 1 0 0000 NO 14 0000 55 5000 3 SUB10X C SUB10 C CKT1 ACSR FINCH 0 0000 NO 1
134. ion Line Counterpoise Ground 68 6 2 Enhancing the Substation Grounding System 74 Appendix A1 Using the Cable Library Editor 79 Appendix A2 Clearance Analysis 90 Appendix A4 Lightning Shielding Analysis 98 A4 1 Electro Geometric Method 101 A4 2 Rolling Sphere Method 106 Appendix A3 Selection of Ground Conductor Size 109 Appendix B Applications Guide 111 Appendix B0 Overview 111 Appendix B1 Isolated Grounding System Analysis 113 B1 1 Inspection of System Data 113 B1 2 Analysis of Example System 126 B1 3 Inspection of Results 127 B1 4 Discussion 133 Appendix B2 Steady State Power Flow Analysis 135 B2 1 Inspection of System Data 135 B2 2 Analysis 135 B2 3 Inspection of Results 135 Appendix B3 Short Circuit Analysis 140 B3 1 Inspection of System Data 140 B3 2 Analysis 141 B3 3 Inspection of Results 142 Appendix B4 Ground Potential Rise Computations 151 B4 1 Inspection of System Data 151 B4 2 Analysis 152 B4 3 Inspection of Results 152 Appendix B5 Design of Distribution Substation Grounding System 157 B5 1 Inspection of System Data 158 WinIGS Training Guide Page 3 Page 4 B5 2 Analysis B5 3 Inspection of Results Appendix B6 Design of Transmission Substation Grounding System B6 1 Inspection of System Data B6 2 Analysis B6 3 Inspection of Results Appendix B7 Design of Generation Substation Grounding System B7 1 Inspection of System Data B7 2 Analysis B7 3 Inspection of Results Appendix B
135. ircuit Figure 3 9 illustrates an example of a Voltage Profile report along the distribution line from BUS40 to BUS60 To view this report click on the Circuit Profile radio button located along the main program toolbar and then double click on the distribution line diagram Note the voltage variation along the phase wires which is due to voltage the induced by the neutral current Page 144 WinIGS Training Guide c5 eim Copy Print Help Device Graphical V I Report Return Case Short Circuit Analysis Example System ESTE Transmission Line BUS10 to BUS30 kV 1 48D 63 11 A 28 63D 51 91 kV 119 01D P 5 044 kA 166 66D 62 90 kV 117 56D e 34 76 A 42 94D 3 398 kV 19 42D e 822 1 A 2 40D 3 398 kV 19 42D 800 4 A 1 00D 65 92 A 147 21D 85 87 kV 14 1 j D 4 634 kV 171 53D e 5 046 kA 13 35D 77 02 kV 102 97D a 36 26 A 144 03D 4 634 kV 171 53D e f uU 1 085 kA 176 17D 4 634 kV 171 53D 1 062 kA 178 70D le 2 938 kA 155 79D ISV le 3 398 kA 19 42D Ploss 62 51 MW Figure 3 6 BUS10 to BUS30 Terminal Transmission Line Voltages and Currents during a Phase B to neutral fault at BUS30 c5 5 xX Return g Copy Print Help Device Graphical V I Report Case Short Circuit Analysis Example System Device Transmission Line BUS30 to BUS20 85 87 kV 1
136. ircuit Test Data Per Cent Winding Impedances Ohms Winding Leakage Base MVA Resistance Reactance ps 01 51 280 0 eevee 5 0636 pti 01 65 2800 C Per Unit 5 0636 st 01 82 2800 Per Cent 0 030024 Display Circuit Sequence Parameters PU Core Parameters PU X Pos Neg I S LL Nominal Core Loss 0 005 0 05100 Primary Zero 9 0 01700 Nominal Magnetizing Current 0 005 Second Zero 0 03400 Base MVA 280 00 Ground Zero 0 04800 n Primary Bus Name kV Rating L L Circuit Number a E XF 2 230 0 Np As Secondary Bus Name kV Rating L L Bs XF 1 115 0 Cs de Tertiary Bus Name kV Rating L L eti NEWBUS3 13 8 Delta C Wye Figure 3 17 Autotransformer Parameters Window Page 26 WinIGS Training Guide is Seo Copy Print Help Select Device Cancel Accept Description substation Model Transformer 2 Winding 3 Phase Transformer 3 Winding 3 Phase AutoTransformer with Tertiary 3 Phase AutoTransformer without Tertiary 3 Phase Transformer with Secondary Centertap Single Phase Transformer 3 Phase Sequence Par Grounding System Geometric Model Generalized Conductance Matrix Model AC DC Converter 3 Phase Transformer 4 Winding 3 Phase Transformer Two Winding Single Phase Transformer 3 Winding Single Phase Autotransformer without Tertiary Single Phase Autotransformer with Tertiary Single Phase Delta ZigZag Transformer Paracit
137. is recommended to use higher values such as backup protection clearing times in the event of primary protection failure WinIGS Training Guide Page 57 The touch and step voltages are computed for two conditions a over native soil and b over insulating layer The radio buttons next to these fields set the default permissible values to be compared to actual touch and step voltages In this example we assume that the entire substation area 1s covered by gravel and thus the permissible touch voltage over insulating layer should be selected On the other hand it is recommended to select the permissible step voltage over native soil as the default criterion since the maximum step voltage typically occurs outside the substation Table 5 1 Typical Values of Fault Clearing Time System Voltage Primary Clearing Time seconds UHV 345 kV to 764kV 0 03 to 0 10 UHV 115 kV to 230kV 0 05 to 0 10 Subtransmission 35 kV to 69kV 0 03 to 0 50 Distribution 12 kV to 25 kV 0 08 to 0 50 Distribution 4 to 12 kV 0 08 to 2 0 Equipotentials amp Safety Assessment This button switches to Safety Assessment mode In this mode a number of mode specific buttons appear on both the vertical and horizontal toolbars which allow the selection of the safety analysis type touch voltage step voltage etc the safety analysis region and various visualization parameters Figure 5 13 illustrates the ground model view window in Safety Assessment mode I
138. is section WinIGS Training Guide Page 123 lni x Copy Print Help Wenner Method Field Data Cancel Accept Isolated Grounding System Example Print Copy Import Export Example Grounding System Default Probe Spacing Probe Length Resistance Apparent Resistivity in Feet a in inches L in Ohms V I Ohm Meters 11 600 222 15 224 07 210 66 Dynamic Model Fit Report 109 30 wo 189 60 Corrected Measurement 6 3500 3000 2700 180 08 Model 245 13 8 4500 3000 1900 163 74 E w 9 sooo 23000 1700 162 78 160 87 g 67 020 E 15321 a 153 21 EC o EH J 16 zl 100m 0 00 20 0 40 0 60 0 80 0 100 Delete Measurement Bad Measurements Equivalent Separation Distance feet Delete All Measurements Mark Unmark Unmark All Distance M Ran Mane Probe Diameter 0 625 inches MHHISNESFHES Model Corrected Default Probe Length 30 00 inches Pe Vis cun pe UbperRho 25850 am Model Data Fi Operating Frequency 72 00 Hz M Remove Induced Voltage 5 A Lower Rho 109 57 Qm e 9 9 Layer Depth 25 33 feet Computations Completed 4 c ensitivity 3 Layer Model Fit Soil Model STOP Process State Limits Objective 0 712304 Figure 1 15 Wenner Method Field Data Entry Form after Analysis Copy Print Help Wenner Method Soil Parameters Close Case Name IGS AGUIDE CH01 Description
139. l Parameters Area 0 0 KCM E Diameter 0 000 inches Resistance 1 410 Ohms mile qe Material r Number of Strands 0 TNI Jacket Parameters Lave Diameter 0 000 inches y Overall Diameter 0 000 inches Group Permitivity 0 000 Conductivity 0 000 Mhos meter Jacket Armor 0 00 1 30 2 60 3 90 For Help press F1 Active Layer 0 Figure A1 3 Cable Editing Window Click on the New button to insert a new cable into the library This action opens the cable editing view illustrated in Figure A1 3 Double click on the Name and Manufacturer area of the cable editor view to open the General Parameters window shown in Figure A1 4 If the cable is metric click on the Metric radio button Enter a name for the cable the manufacturer company name the rated voltage ampacities weight and bending radius The name of the cable must be unique 1 e not the same as another cable already included in the library Note also that the weight of the cable can be automatically updated once the cable component entry has been completed using the Compute button on this window Click on Accept button to close the window and return to the editing view At this point there are two ways to proceed in defining the cable structure a Use the cable wizard tool which automatically creates the cable components after specifying a number of cable parameters and b Manually create the cable components and define the component properties Page 8
140. l accurately captures the electrical characteristics of the soil and that the model parameters have been accurately computed Note that most of the measurements red dots are very close to the green curve except for the 7 and the 11 measurements This suggests that the 7 and the 11 measurements contain a large error and thus they may be classified as bad data These bad data can be excluded from the analysis generally resulting in reduction of the soil model parameter tolerance To exclude data click on each data row to be excluded and then click on the Mark Unmark button The marked row entries will become gray as illustrated in Figure 4 19 Click again on the process button to repeat the analysis while excluding the marked data Figure 4 20 shows the 2 layer soil parameters computed with the 2 marked data excluded Note that the tolerance values are much lower than the ones originally obtained by processing all data Figure 4 18 This completes the modeling of the grounding system preliminary design We are now ready to perform safety analysis which 1s presented in the next Section r Landi Copy Print Help Soil Resistivity Data Interpretation Study Case Isolated Grounding System Example Grounding System Grounding System Geometric Model Soil Data Type User Specified 2 Layer Soil Model C User Specified 3 Layer Soil Model Under Development Schlumberger Palmer Method Driven Rod M
141. lGs Grounding System Geometric Model Case IGS TGUIDE 01 File Edit Select View Insert Transformations Tools Window Help Edit Mode 176 79 y 256 42 ft Grid Spacing 100 0 ft Analysis Reports Tools aaa drawing ipg Cond 0 Size 0 Group f WinlGs Grounding System Geometric Model Case IGS TGUIDE 01 Model A Layer Group Depth Type le A G Advanced Grounding C cepts WinIGS S et SDA Sue z 7 Meqh File Edit Select View Insert Transformations Tools Window Help x 22 83 y 0 26 ft Grid Spacing 100 0 ft Mode A Edit Mode HEN Analysis Reports Tools i Undo R do C WMstrDoc WinlGS Training_Guide gnd_drawing jpg Cond 0 Size 0 Group 7 8 9 E Li UE Group Depth Type SDA Size Scale t tLevel Freeze For Help press Fl Figure 4 5 Ground Editor with Imported Image File a initial location of reference line segment b reference segment positioned over known length line WinIGS Training Guide Next open the layers window and uncheck the Edit check box corresponding to the 7 layer drawing layer The drawing layer is now Uneditable so that it cannot be accidently selected moved or resized as we edit the grounding system Also click on the Act radio button corresponding to the Fences layer so that we can start entering the fence model then click on the Accept
142. le Ground Rod Cancel X Coordinate feet 0 000 GAGE Sa Y Coordinate feet 90 000 Rod Top End Depth feet positive 1 500 Rod Length feet 20 000 Type COP_CLAD Connector Type Size 3 4 None Exothermic Group MAIN GND Compression vc Screw Layer Grounding Electrodes Other Figure 1 10 Ground Rod Parameter Form Accept Perimeter Ground Conductor Cancel Conductor Segment Coordinates feet Update Diagram X feet Y feet 1 174 000 90 000 2 174 000 90 000 3 174 000 90 000 4 174 000 90 000 5 174 000 90 000 zj Add Vertex Remove Vertex Burial Depth positive 1 500 Conductor Specifications Group MAIN GND Type COPPER Size 2 Layer Grounding Electrodes Figure 1 11 Polygonal Conductor Parameter Form Page 120 WinIGS Training Guide Note that the conductor type and size specifications are selectable from conductor libraries Specifically clicking on the conductor type or size fields opens the conductor library window which is illustrated in Figure 1 12 Conductors are selected by clicking on the desired type and size entries and then clicking on the Accept button R Copy Print Help Conductor Library Accept 6 ACSR Sort by Name Sort by Size Cancel 7 ACSR DIAM 8 ACSRAW AWG DCRes Area Dia Strands Ampacity 9 ACSREHS 1 1 2 0 3380 250 0 0 5180 9 10 ALUMINUM 2 3 8 0 3380 250 0 0 5180 11 ALUMOWE S 5
143. lent Source at BUS 10 Cancel Source Voltage Bus Name Line to Neutral 66 395 kV Update L N BUS10 Line to Line 115 000 kV Updatel L Ei Phase Angle 0 0 Degrees C Positive Phase Sequence Ne gative oc S Zero Circuit Number 1 Source Impedance Ohms E Positive a 0 00 5 1350 0 MVA Sequence Reactance 9 7963 1 0 115 0 kV L L Negative Resistance 000 00 6 778 kA Reactance 9 7963 10 9 796 Ohms Sequence Zero firas 0 00 0 0 Reactance 9 7963 1 0 Update Ohms Update PU Sequence Figure 3 7 Source Parameter Editing Window To complete the source model we also need to represent the source ground impedance Enter a Ground Impedance Model third entry in Figure 3 6 and connect it at the same bus as the equivalent source as illustrated on the left You S10 can view the parameters of the ground impedance model as for all devices in WinIGS by left double clicking on the model icon Note that the default ground impedance value is 1 0 Ohm You can accept the default value as the effect of this parameter on the substation under study is very small Continue by creating equivalent sources at the remote ends of the other three transmission lines with the source parameters as given in Figure 2 1 The network view should now resemble the one illustrated 1n Figure 3 8 Page 18 WinIGS Training Guide S10 SUB10 SUB30 BUS30 2 T
144. lick on the Reports button to enter into the report viewing mode Select the Graphical I O mode and double click on all system components to view the voltage and current reports The results should be consistent with normal system operation Specifically the three phase voltages should be nearly balanced phase voltage magnitudes should be near nominal values neutral voltages should be low and current magnitudes consistent with the system load For example Figure 6 4 shows the voltages and currents at the substation auto transformer terminals after base case solution was computed Device Graphical VO Report Return Case Transmission Substation Grounding System Design Device AutoTransformer with Tertiary BUS20 to BUS30 133 2 kV 0 02D 6 239 A 84 88D 133 2 kV 120 03D 7 991 kV 89 97D 59 35 mA 135 03D 6 185 A 150 29D 133 2 kV 119 99D 6 150 A 37 62D A 156 8 mV 14 72D P 7 993 kV 30 02D e 9 176 4 mA 129 54D S 66 58 kV 0 02D 59 36 mA 104 98D 11 17 A 87 65D 66 57 kV 120 02D 7 993 kV 150 03D 10 85 A 36 41D 66 57 kV 119 99D 59 35 mA 15 03D 10 50 A 150 38D asv Program WinlGS Form FDR GDIO Figure 6 4 Base Case Solution Autotransformer Voltage and Current Report Page 174 WinIGS Training Guide The next step is to determine the fault conditions that generate the highest ground potential rise GPR at
145. lly the parameters of the transmission and distribution lines B9 2 Analysis Click on the Tools button located at the top right corner of the main program frame Select the transmission line BUS20 to BUS30 by clicking on it single left mouse button click Click on the Line Parameters button on the second row of buttons of the main program frame This action opens the Transmission Line Parameters selection form illustrated in Figure 9 2 This form provides three options a Sequence Parameters b Mutual Zero Sequence Parameters and c Generalized Pi Equivalent Circuit Page 194 WinIGS Training Guide Transmission Line Parameters Sequence Parameters Mutual Zero Sequence Parameters Generalized Pi Equivalent Cancel Click on Help for a description of the above options Figure 9 2 Transmission Line Parameters Selection Form Click on the Sequence Parameters button to open the Sequence Parameters form which is illustrated in Figure 9 3 This form summarizes the line construction parameters conductor sizes distances line length etc as well as the total line pi equivalent sequence parameters Series impedances are given in both Ohms and Shunt admittances are given in both milli Mhos and These parameters are computed at the system base frequency 60 Hz in this example The selected transmission line element comprises two circuits and by default the form displays the parameters of the first circuit You can v
146. ls 1 Figure 5 18 Creating an Equipotential Scale Element Position the equipotential scale element arrow so that it intersects the equipotential curves to be annotated You can move this element by left clicking along its axis or resize reorient it by manipulating its end points Left double click on it to open the associated properties dialog window also shown in Figure 5 17 Set the Font Size expressed in feet to a value appropriate for the physical size of the area to be annotated Note that if the font size is too small the numeric values may not be visible and if too large the numeric values may be overlapping In this example a value between 1 5 and 2 feet works well Click on the accept button to close the equipotential scale properties window then left click on a point away from this element to deselect it Once the scale element is deselected a numeric value indicating the contour voltage appears along each curve at the location where the scale element intersects each equipotential contour An alternative way to easily visualize the locations where violations occur is the 3 D render view mode Click on the button titled 3D Plot or the vertical toolbar button to open the 3D rendered view mode The 3D visualization view for this example is illustrated in Figure 5 18 Note that the touch voltage is represented by a surface whose height above the earth surface is proportional to the touch voltage value over each earth surfac
147. m WinIGS and open the study case titled E IGS AGUIDE CHO0I Use command Open of the File menu or click on the icon to open the existing study case data files Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the study case files are opened the network editor window appears showing the system single line diagram as illustrated 1n Figure 1 1 The example system consists of a grounding system a current source a source ground and a resistor The source and the source ground are connected to the bus SOURCE The ground system is connected to the bus GRSYS A 1 0 Ohm resistor is connected between the SOURCE and GRSYS buses Note that each bus consists of a number of nodes Each node is identified by a unique name Node names begin with the bus name they belong to and end with an extension WinIGS Training Guide Page 113 consisting of an underscore and one or more alphabetic characters Commonly used extensions in 3 phase systems are _A _B _C _N _G and in secondary distribution systems L1 L2 NN GG For example the SOURCE bus consists of a phase node named SOURCE_A and a neutral node named SOURCE_N The source circulates a user specified current between nodes SOURCE_A and SOURCE_N The source ground is connected to the node SOURCE_N You can verify the node connectivity at any bus by double clicking on the bus symbols red squares For example by double clickin
148. mation is imposed then the sequence parameters of the line are computed with the standard application of the symmetrical component transformation Therefore the sequence parameters represent an approximate line model It should be emphasized that all WinIGS analysis functions use the exact admittance matrix based model A detailed presentation of the mathematical procedure leading to the computation of the transmission line generalized admittance matrix as well as the and the sequence parameters is given in the text A P Meliopoulos Power System Grounding and Transients An Introduction Marcel Dekker Inc 1988 Chapter 6 sections 3 4 5 6 7 8 and 9 B9 1 Inspection of System Data Execute the program WinIGS and open the study case titled IGS_AGUIDE_CH09 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 9 1 is displayed The example system includes of three transmission lines two are mutually coupled from BUS20 to BUS30 and one is on a Separate right of way from BUSIO to BUS30 one equivalent line two equivalent sources a delta wye connected transformer a 12 kV distribution system loop with an open switch in the loop three phase loads as well as single phase loads along the distribution system and appropriate grounding Inspect the device parameters and specifica
149. me v i All Modes odds Earth Voltage Only Accept Frame Applicability lt Touch Voltage Only Step Voltage Only Cancel Conductor Voltage Only Touch Voltage Reference Nearest Grounding System Point Model B only User Specified Group or Terminal GRSYS N Step Voltage Distance 3 000 feet l Specify Permissible Voltages Resolution 150 points Equipotential Contours Linear Number of Contours 10 Logarithmic Number of Decades 3 Color Code Legend Font Size Factor 1 000 T Opaque Legend v Show Enclosed Area Specified Contour Draw a Contour at 300 000 Volts Figure 1 24 Plot Frame Parameters Form In order to view the touch voltage distribution close the Plot Frame Parameters form select the Touch Voltage option i e click on the Touch Voltage radio button and then click on the Update button After a short delay the equipotential touch voltage plot WinIGS Training Guide Page 131 appears superimposed over the grounding system drawing in top view mode This plot is illustrated in Figure 1 25 The Touch Voltage Equipotential plot consists of color coded contours These contours follow paths of equal touch voltage A legend at the right side of the plot frame indicates the touch voltage level associated with each line color The legend at the top of the plot frame displays the maximum permissible touch voltage Vperm 736 Volts and the actual maxi
150. mercial Installation 4l Yellowjacket Substation J Substation Gr rounding System Scale feet March 12 2002 AGC WINGS 2002 EX0001 1 o Adv S 6 7 8 9 10 11 l 12 13 14 E S2 gu A Figure 5 12 Plot Frame Parameters Form for Commercial Installation Grounding System Area DISTR group Next click on the 3D Plot button of the main toolbar to view the touch voltage Lire distribution in 3 D surface plot mode see Figure 5 14 Click on the umi to check or modify the plot color mapping the pop up window is shown in Figure 5 13 Click on the button Allowable Touch to automatically set the thresholds at allowable touch voltage yellow to red 715 9 Volts and 50 of allowable touch voltage green to yellow at 358 0 Volts Then click on the Close button Note that the actual touch voltage violates the maximum allowable touch voltage limit in many locations identified by red color You can also click on the ita button to display the maximum allowable touch voltage plane a horizontal planar surface indicating the maximum allowable touch voltage level Page 168 WinIGS Training Guide Copy Print Help Single Color e Multi Color Max Voltage Colors BEEF Thresholds E AY Zo E Low Min Voltage FT Allowable Touch Allowable Step ZO Figure 5 13 3 D Surface Plot Voltage Thresholds and Colors Figure 5 14 3 D Touch Voltage Plot At this
151. mount of data entry since most of the parameters of the two 115 kV lines are identical Note that the bus names at the two ends of the transmission lines can be also edited via the transmission line parameter editing window It is important that each bus has a unique name WinIGS assumes that buses with identical names are implicitly connected together so ensure that all distinct buses have unique names Note also that the program displays unique buses in red color and repeated buses in blue color Thus inadvertently repeated bus names can be easily spotted Next enter the four equivalent sources at the ends of the four transmission lines Use the T toolbar button command Insert Shunt Device to open the shunt device selection window illustrated in Figure 3 6 Select the second entry titled Equivalent Source 3 Phase and click on he Accept button Then click at the desired location to insert the source model WinIGS Training Guide E ce em Copy Print Help Select Device Cancel Accept Description Substation Bus Interface Equivalent Source 3 Phase Ground Impedance Model Voltage or Current Source Single Phase Transformer Zig zag Capacitor or Inductor Bank 3 Phase Load Constant Impedance Single Phase Load Constant Impedance 3 Phase Load Constant Impedance Secondary Bus Balanced Photovoltaic Cell 4 2 3 4 5 6 f 8 9 10 Figure 3 6 Shunt Device Selection Window Next left double
152. mum touch voltage occurring within the plot frame area Vmax 1724 V The location of the actual maximum touch voltage is indicated by a sign near center of upper right mesh of grounding system Note that the actual maximum touch voltage exceeds the maximum allowable value as defined by the IEEE Std 80 A c ol D 1 2 3 4 5 6 7 8 9 10 11 12 13 1 Equi Touch Voltage Plot with respect to GRSYS N Enclosed Area 62596 5 sq feet Vperm 736 V Vmax 1 724 kV i 6 LZ XT NUNT R9 ce 462 9 V 589 0 V q 715 1 V 841 2 V 967 3V 1 093 kV 1 220 kV 1 346 kV 1 472 kV 1 598kV August 22 2002 35 70 105 Advanced Grounding Co s WinlGS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 iS 16 Figure 1 25 Touch Voltage Report Equipotential Plot The touch voltage distribution can be visualized using a 3 D surface plot illustrated in Figure 1 26 The actual touch voltage 1s represented by the curved surface The curved surface color mapped to identify touch voltage violations For example red color indicates that the touch voltage exceeds the allowable value To view this plot click on the 3D Plot button of the main toolbar or the As button of the left vert
153. n order to generate equipotential plots the region of interest must first be defined For example touch voltage is of interest anywhere a person can be standing and being able to touch any conductive structure which is bonded to the grounding system In a typical substation the entire area enclosed by the substation perimeter fence including the region extending 3 feet outside the fence must be considered On the other hand step voltages Page 58 WinIGS Training Guide Safety Criteria IEEE Std80 2000 Edition Close Electric Shock Duration 0 350 seconds View Plot Permissible Body Current 0 196 Amperes IEEE Std80 2000 Body Weight J 70kg e 50 kg Probability of Ventricular Fibrillation 0 5 O IEC Body Resistance 5 GO 50 95 Probability of Ventricular Fibrillation gt 0 14 05 5 5 DC Offset Effect Fault Type Circuit Fault XIR Ratio 3 2659 Faulted Bus FAULTBUS Decrement Factor 1 0123 Permissible Touch Voltage Over Insulating Surface Layer 6146V e Over Native Soil 2645V Hand To Hand Metal to Metal Sea Permissible Step Voltage Select 1 Over Insulating Surface Layer 18774V C Over Native Soil 40V e Figure 5 12 Safety Criteria Selection Dialog are typically higher a few feet outside the perimeter fence than anywhere within the fence enclosed area Thus different analysis regions for touch and step voltages must be con
154. nIGS Training Guide Page 9 Control House Figure 2 2 Equipment Foundation Layout WinIGS Training Guide Page 10 4 28 0 j N1 N1 67 8 feet 55 5 Figure 2 3 115 kV Transmission Line Tower 40 0 N1 e N1 Bie e A 1 C 1 100 7 feet 80 feet Figure 2 4 230 kV Transmission Line Tower WinIGS Training Guide Page 11 Table 2 1 Soil Resistivity Measurements Collected Using the Wenner Method Sample Probe Spacing Resistance Number Ohms 1 Probe Length in contact with soil 12 inches Meter Operating Frequency 72 Hz Page 12 WinIGS Training Guide 3 Creating a Network Model The first step in creating a WinIGS model is defining a study case file using the File menu New Case command Execute the WinIGS program and click on the New Case qe command or the vertical toolbar button In the pop up window illustrated below enter the desired Case Name and optionally a case description phrase then click on the Create button Note that WinIGS does not allow spaces in case names Spaces in case names are automatically replaced by signs Create a new WinlGS Study Case study Type Frequency Domain IGS Case Mame Training E ample 1 Cancel Description inl Training E ample Syster Directory CAIGS DAT ALS Drive ic Fined Disk Up One Level New Directory Delete AGC Pa
155. nding system The driving point resistance at a node of a multi terminal network is the node voltage divided by the current injected into this node while all other nodes have zero current injections Page 162 WinIGS Training Guide WinIGS also computes the mutual resistances among all nodes of a multi terminal grounding system so that transfer voltages among the grounding systems can be computed The full grounding system model can be viewed by clicking on the View Full Matrix button of the Grounding System Voltage and Current Report This report displays the grounding system resistance matrix and is illustrated in Figure 5 7b Note that the driving point resistances are the diagonal elements of this matrix Copy Print Help Study Case Title Grounding System ini x Close Distribution Substation Grounding System Design Distribution substation grounding system Group Name Node Name Resistance Voltage Current Ohms Volts Amperes MAIN GND COM DIST Resistance Definition SUB1 N 36 8 49 1206 16 1420 33 1 3166 7 5908 4 0726 COM_N DIST_N Rp 1 1051 Split Factor Driving Point C Equivalent Circuit Shunt Branch Earth Current Fault Current 2193 87 0 00 0 00 2193 87 6895 12 40 52 View Full Matrix Figure 5 7a Grounding System Resistance Report WinIGS Training Guide Page 163 Ter 1ni xl Copy Print Help ENEEENNCTUTUDTTUCIDTONSEEENNNNNE o
156. ning Shielding button This action reopens the grounding system CAD window in LSA mode Click on the le button to enter the Rolling Sphere Analysis Mode A Rendered 3 D window opens showing the grounding system along with a dialog window containing the analysis controls illustrated in Figure A4 12 Setup the parameters as illustrated in Figure A4 12 and the n click on the left toolbar button to open the layer selection window illustrated in Figure A4 13 Check the box next to the Phase Conductors title then click on the Accept button This action selects all phase conductors so that the WinIGS Training Guide rolling sphere analysis will compute the exposed area for the system phase conductors Click on the Auto Scan button to execute the rolling sphere analysis Standard IEEE 1985 Historical EPRI Red Book x l J L Exp Area mz Lightning Current 10 00 EA Sphere A adius 35 7 meters T ss Max Sky Step FOO meters Animation sky Step 18 meters Transpar Auto Scan Stop Clear Traces Copy Print Help Lee select Layers Cancel Accep Select Page 1 of 16 E Grounding Electrodes Fences Foundations Control Building Bus Phase Conductors Rigid Line Phase Conductors Flexible Electrical Equipment Shield Wires Bus Supports Lightning Poles f aa 1 7 a xI 1 2 3 4 5 6 T 8 9 10 Layer 13 Layer 14 Layer 15 Layer
157. ning the analysis and inspecting the results 3 Ph Eq Cell mm mm Equiv Source BUS20 BUS10 Equiv Source D j gt Substation 1 Figure 4 1 Single Line Diagram of Example System IGS AGUIDE CH04 B4 1 Inspection of System Data In order to run this example execute the program WinIGS and open the study case titled IGS AGUIDE CHO4 Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 4 1 is displayed You can inspect the parameters of the example system components and make any desired changes by double clicking of the component icons Once the inspections and modifications are completed save the study case and proceed to the analysis section WinIGS Training Guide Page 151 B4 2 Analysis The objective of this example is to demonstrate the developed ground potential rise over various parts of the power system during faults It is recommended that a base case analysis is performed first in order to verify that the system model is consistent Click on the Analysis button and select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis is completed a pop up window appears indicating the completion of the analysis Click on the Close button to close this window and then click on the Reports button to
158. nternal I O Report Example WinIGS Training Guide Page 137 Copy Print Help Device Terminal Multimeter Close Case Power Flow Analysis Example Device Power Transformer 115kV 12kV 20MVA Side 1 Side 2 3 Phase Power 7 Voltage ip LG Phase Quantities v Per Phase Power Current LL Symmetric Comp Impedance Voltages P 164 0 kW Q 92 24 kVar BUS30 A 6 Ic S 188 1 kVA PF 87 16 Pa 54 78 kW Qa 30 95 kVar BUS30B 6 Pb 54 42 kW Qb 30 75 kVar BUS30 C e e Pc 54 76 kW Qc 30 54 kVar Van 64 04 kV 10 36 mDeg J BUS30 N e lt Vbn 64 04 kV 120 0 Deg Ref 3 Vcn 64 04 kV 120 0 Deg Currents la 982 5 mA 29 47 Deg BUS30_A 2 gt Ib 976 0 mA 149 5 Deg Ic 979 1 mA 90 85 Deg BUS30 B 6 BUSS0C Figure 2 5 Multimeter Report Example In addition to selective device reports the system voltages currents and power flows can be overlaid on the single system line diagram The desired displays are selected using the command Result Display Selection of the View menu or alternatively by clicking V on the toolbar button This command opens the dialog window illustrated in Figure 2 6 a Copy Print Help Clear All Displays Bus Voltage Displays mU Color Color Result Display Font Size 100 00 Color Bus Name Font Size 20 pixels Color jus Name Font Angle 0 degr
159. nverted line model in order to add the counterpoise conductor and change the line length to 0 16 miles two spans The parameters dialog window of the mutually coupled multiphase line model is shown in Figure 6 4 To add the counterpoise ground select the 5 conductor in the Conductors table then click on the copy button to create a new conductor 6 line in Conductors Table Edit the new conductor parameters by double clicking on the 6 line of the Conductors table Change the X and Y coordinates so that the new conductor is 5 feet below grade directly below the center of the line support structure i e set X 0 0 and Y 5 0 feet WinIGS Training Guide Page 69 BUS20 SUB10X fe BUS2 BUSA GND PX AEE xem Grounding System BUS30 BUS40 4 4 Figure 6 2 Example Network Model with Counterpoise Ground Added Finally verify that the line configuration is as expected by clicking on the View Configuration button of the Mutually Coupled Multiphase Lines parameter window Click on the Accept button close the Mutually Coupled Multiphase Lines parameter window Next add a Ground Impedance Model at the connection point between the existing overhead line and the added mutually coupled multiphase line models Node SUBIOX This model represents the grounding of the line support tower located at the at the two line interconnection point Note that all WinIGS transmission line models represent the grounding of the support
160. ode Page 182 WinIGS Training Guide Select the Graphical I O mode and double click on all system components to view the voltage and current reports The results should consistent with normal system operation Specifically voltages should be nearly balanced Phase voltage magnitudes should be near nominal values neutral voltages should be low and current magnitudes consistent with the system load For example Figure 7 3 shows the voltages and currents at the station auto transformer terminals after base case solution was computed Device Graphical VO Report Return Case Generation Substation Grounding System Design Device ThreePhase AutoTransformer with Tertiary 132 9 kV 29 98D 1 232 A 42 88D 132 9 kV 90 02D 7 972 kV 119 97D 59 20 mA 105 03D 954 5 mA 169 39D 132 9 kV 149 98D 1 192 A 96 43D YA 144 2 mV 45 12D P 7 972 kV 0 02D e p 107 6 mA 171 28D S 66 43 kV 29 98D 59 20 mA 134 98D 1 913 A 126 32D 66 43 kV 90 02D 7 972 kV 120 03D 1 352 A 4 43D 66 43 kV 149 98D 59 20 mA 14 97D 1 625 A 87 86D Program WinlGS Form FDR_GDIO Figure 7 3 Autotransformer Terminal Voltages and Currents Base Case Analysis The next step is to determine the fault conditions that generate the highest ground potential rise GPR at the substation grounding system in order to verify the system safety under worst possible condition For thi
161. ogram WinlGS Form MAX VOLTAGE Figure 10 5 Maximum Induced Transfer Voltage Analysis Results Summary Page 204 WinIGS Training Guide Device Graphical I O Report Return Case Induced Transferred Voltage Computations Device Mutually Coupled Multi Phase Lines 884 5 V 73 89D 1 919 kA 81 92D 5 522 kV 31 11D 1 919 kA 98 08D 8 321 kV 161 49D 62 95 A 3 72D 6 749 kV 153 18D 62 88 A 176 38D 7 758 kV 103 38D 63 31 A 95 18D 7 287 kV 89 76D 63 30 A 84 94D 884 5 V 73 89D 1 227 kA 102 65D 378 5 V 97 60D 1 090 kA 73 95D 378 5 V 97 60D 19 77 mA 137 79D 1 128 kV 152 69D 18 51 mA 47 62D asv Program WinlGS Form FDR_GDIO Figure 10 6 Distribution Line Terminal Voltages and Currents During L N Fault at BUS60 Device Terminal Multimeter Close Case Induced Transferred Voltage Computations Device Mutually Coupled Multi Phase Lines Side 1 Side2 3Phase Power m FUR AERE is L G Phase Quantities L Per Phase Power Current O LL Symmetric Comp Impedance Voltages V1 1 851 kV 132 4 Deg COMMCIRN 6vi I1 1 919 kA 81 92 Deg I2 1 227 kA 102 7 Deg none v2 none e v3 BUS60 N Ref Currents BUS60 A G n BUSSON i2 none 13 Program WinIGS Form IGS MULTIMETER Figure 10 7 Multimeter Report Showing Voltage Acr
162. on to open the insert electrode window shown in Figure 4 8 Select the 9 row element titled Polyline Ground Conductor Also modify the default layer to Ground Conductors then click on the Insert button Next sequentially left click on points located approximately 3 feet from away from the perimeter fence corners and terminate the entry mode by clicking on the right mouse button To improve the conductor positioning accuracy zoom in and reposition the corner points as necessary As with the fence element you can also add or remove and selected corner points using the toolbar buttons respectively HINT you can insert dimension lines to help accurately reposition the perimeter conductor at the desired distance from the fence To create a dimension line click on the toolbar button E Insert reference objects and select the 7 row titled Dimension Line Click on the insert button then click and drag on the drawing to create a dimension line at the desired location See Figure 4 10 Next left double click on the perimeter conductor to open its parameters window illustrated in Figure 4 11 Note that in addition to the corner coordinates editable parameters include the conductor burial depth the conductor type and size the fence post spacing the Group name MAIN GND and the Layer Ground Conductors Modify the default Copper 4 0 conductor size to Copper 2 0 then click the Accept button to close the parameter wind
163. on grounding system or enhancing the grounding of the transmission lines reaching the substation Next repeat the presented analysis procedure to evaluate the enhanced system performance Note that it may be necessary to repeat this analysis enhancement cycle several times before an acceptable safety performance is achieved Page 180 WinIGS Training Guide Appendix B7 Design of Generation Substation Grounding System This section illustrates the application of the WinIGS program to the analysis and design of a generation substation grounding The presentation is based on an example system under the study case name IGS AGUIDE CH07 The WinIGS data files for this example system are included in the program installation The single line diagram of the example system is illustrated in Figure 7 1 The generating station has two generating units one 18 kV 300 MVA unit with an 18 kV 230 kV step up transformer and one 15 kV 250 MVA unit with a 15 kV IISkV step up transformer and a 115 230 kV autotransformer The 3 D view of the station illustrating the grounding system and major equipment and structures is illustrated in Figure 7 2 Rm mm m m IR PR tmm am m Ibm UR Se IP UR o SR REIR HE 0h eS eS RAN UR RA Ge UAR GR IS Ran o RU im IN RR GR 5 S98 dom 9S mim em m qim m Fn S SRS SS m RR m SSE mmm Figure 7 1 Generating Station Example Single Line Diagram WinIGS Training Guide Page 181 Figure 7 2 Generating Station 3 D View Illustrating Groundin
164. oss Communications Load and Distribution Line Phase A and Neutral Currents at BUS60 WinIGS Training Guide Page 205 Appendix B11 Harmonic Propagation Computations This section illustrates the capability of the program WinIGS to perform harmonic analysis and harmonic propagation along power systems The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH11 The single line diagram of the example system is illustrated in Figure 11 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results 3 Ph Eq Cid GE GN ED BUS20 BUS10 Equiv Source Equiv Source Figure 11 1 Single Line Diagram of Example System IGS AGUIDE CH11 B11 1 Inspection of System Data Execute the program WinIGS and open the study case titled IGS AGUIDE CHII Note that the example study case data files are placed in the directory IGS DATAU during the WinIGS program installation Once the example data files are loaded the system single line diagram shown in Figure 11 1 is displayed The example system consists of two transmission lines one equivalent line two equivalent sources a delta wye connected transformer a 12 kV distribution system loop with an open switch in the loop The distribution system contains 4 single phase and 4 three phase loads 3
165. ouch and step voltage computations Use the toolbar button E command nsert Multiterminal to open the multi terminal element selection window illustrated in Figure 3 18 Select the eight entry titled Grounding System Geometric Model and click on he Accept button Click in the area below the 115 and 230 kV breakers to insert the grounding model icon Note that the grounding icon has a single terminal We must connect to this terminal all the neutrals of the system that are bonded to ground In this example we must connect the neutrals on both the 115 kV and the 230 KV sides of the substation to the ground model terminal This can be achieved by inserting two additional two terminal connectors between the ground model terminal and a node at each voltage level 115 kV and 230 kV An example implementation is shown in Figure 3 19 This completes the network side of the model The remaining task for the completion of the integrated system model is to setup the physical ground model of the substation This task is presented in the next section Page 24 WinIGS Training Guide WBUS1 Y A P S CT NEWBUS3 NEWBUS2 BUS2 BUS4 BUS2 BUS4 b Figure 3 16 Entering an Autotransformer Model a Autotransformer icon upon entry b Autotransformer icon after rotation and appropriate connections WinIGS Training Guide Page 25 m1 Copy Print Help 3 Phase Autrotransformer with Tertiary 280 MVA 115 230 kV Auto Transformer Short C
166. ounding system Resistance Voltage Current N N N g acer name ogee Ohms Volts Amperes MAIN GND BUS30_N 3048 71 1953 96 Figure 6 7 Grounding System Resistance Report Next click on the Resistive Layer Effects button to open the reduction factor computation form illustrated in Figure 5 8 This form models the gravel layer covering the substation yard The existing data represent a 0 1 meters thick layer of gravel of 2000 Ohm meter resistivity Reduction Factor IEEE Std80 2000 Edition Update Close Standard Q IEEE Std80 1986 Q Ref1 see Help IEEE Std80 2000 Native Soil Upper Layer Resistivity ph z AA 350 0 Layer Resistivity 2000 0 Layer Thickness m 0 30 0 1000 k Factor 0 7021 0 00 Reduction Factor 0 00 0 050 0 100 0 15 0 20 0 25 0 7467 Layer Thickness meters WinlGS Form GRD RPO02 Copyright C A P Meliopoulos 1998 2004 0 60 Reduction Factor Cs Figure 6 8 Reduction Factor Report Close the reduction factor computation form and then click on the Allowable Touch and Step Voltages button to open the Safety Criteria computation form illustrated in Figure 6 9 Note that the maximum allowable touch voltage according to IEEE Std 80 for a WinIGS Training Guide Page 177 0 25 second shock duration and a 50 kg person is reported to be 722 Volts Note also that the computation of the maximum allowable touch voltage has taken into acco
167. oup name of any ground electrode can be edited by opening its parameter window left double click on the element The ground editor provides several Snapping modes that promote consistency of the edited element geometry The simplest Snapping mode is the Grid Snap which when activated constrains all element coordinates to be multiples of a user selected increment The Grid Snap mode is activated using the tool bar button It is recommended to keep the Grid Snap Mode activated during all editing operations The grid snap increment can be set by the General options window Tool bar button shown in Figure 4 7 Note that the horizontal and vertical increments are separately defined X Y Step field sets the horizontal increment and the Z Step field sets the vertical increment WinIGS Training Guide Page 35 Select Options X Network Editor Grounding Editor DXF GUI System Algorithm Grid Snap Line Snap Vertex Snap Orthogonal Snap Iw Enable Enable Enable Enable X Y Step Z Sep Distance Distance Angle Deg Figure 4 7 Snapping Parameters The WinIGS ground editor provides three additional more advanced snapping options namely Line Snap Vertex Snap and Orthogonal Snap See the WinIGS user s manual for details Let s start by introducing a Fence model by tracing over the fence outline indicated in the provided drawing Click on the toolbar button to open the insert elec
168. ow Page 38 WinIGS Training Guide Copy Print Help Double Click on Element to be Inserted Node Interface Element Smart Ground Multimeter Position Annotation Text Reference Point Polygonal Line Picture JPG PNG BMP TIF Dimension Line igs WinIGS Grounding System Geometric Model Case IGS TGUIDE 01 File Edit Select View Insert Transformations Tools Window Help Edit Mode 4 do m 4153 29 y 215 87 ft 1 l B c Grid Spacing 100 0 ft Model A La sEBRE 19 1 Edit Substation X WinlGS Training Example August 26 20 REV 1 0 Copy Print Help Horizontal Polygonal Conductor Accept Perimeter Ground Conductor 2 0 Copper Cancel Segment Coordinates feet 1 2 3 4 5 6 7 8 9 X feet 224 000 224 000 161 000 161 000 183 000 183 000 91 000 91 000 65 000 Y feet 169 500 19 000 43 000 232 500 232 500 14 500 14 500 134 500 134 500 z Update Diagram Add Vertex Remove Vertex Burial Depth positive 1 500 Conductor Specifications Type COPPER Size 2 0 Group MAIN GND Layer Ground Conductors Figure 4 11 Polygonal Conductor Element Properties Window WinIGS Training Guide Page 39 E WinIGS Grounding System Geometric Model Case IGS TGUIDE 01 ESSENCE For Help press F1 File
169. ple system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH09 The single line diagram of the example system is illustrated in Figure 9 1 BUS 10 N J zu O Equiv Source Equiv Source Substation Figure 9 1 Single Line Diagram of Example System IGS AGUIDE CH09 Transmission line parameters can be presented in one of the following three forms Sequence Parameters 2 Mutual Zero Sequence Parameters 3 Generalized Pi Equivalent Parameters All transmission line parameter reports are based on a generalized transmission line model that explicitly represents the phase conductors the shield neutral ground conductors and the transmission line tower pole grounding systems In all WinIGS analysis functions transmission lines are represented by their exact admittance matrix This approach captures the effects of transmission line asymmetries WinIGS Training Guide Page 193 grounding effects etc Line parameter report option 3 Generalized Pi Equivalent Parameters displays the series and shunt components of the line exact admittance matrix Options 1 and 2 Sequence Parameters and Mutual Zero Sequence Parameter reports display the line sequence parameters which are derived from the line exact admittance matrix by imposing the standard symmetric approximation 1 e phase self impedances and phase to phase mutual impedances are made equal to the corresponding average values Once this approxi
170. ple System IGS_AGUIDE_CH14 Top View Figure 14 3 Grounding System of Example System IGS_AGUIDE_CH14 3D Rendered View WinIGS Training Guide Page 227
171. power factor correction capacitors 2 Wye and 1 Delta connected and 3 grounding systems Page 206 WinIGS Training Guide B11 2 Analysis The WinIGS program provides several functions for harmonic propagation analysis e Impedance Frequency Scan e Transimpedance Transfer Function Click on the Analysis button select the Impedance Frequency Scan analysis mode and click on the Run button This action opens the Impedance Frequency Scan form illustrated in Figure 11 2 Impedance Frequency Scan At a Port Close 2 Node Port Nodes oO BUS70 B BUS70_N Z f gt 3 Phase Bus Port Bus Name Frequency Range 10 00 to 2100 00 Hz Number of Steps 100 Execute STOP Program WinlGS Form FSCAN PAR Figure 11 2 Impedance Frequency Scan Parameter Form This form allows specification of the following frequency scan analysis parameters Port Specification This is the port into which the impedance is computed It can be either a 2 Node port or a 3 phase port A 2 Node port is defined by 2 node names A three phase port 1s defined by a bus name and the excitation mode positive negative or Zero sequence Frequency Range The lowest and highest frequencies to be plotted Number of Steps The number of frequency values where the impedance is computed Select the frequency scan analysis parameters as illustrated in Figure 11 2 and click on the Execute button Afte
172. r 0 5283 lt lt Neutral Conductor Insulation m Outer Diameter 1 1504 i Jacket c Armor Q Area KCM 1044 32 Conduit Thickness 0 3111 C Insulation Shield All linear dimensions in inches Figure A1 9 Examples of Two Cable Component Parameter Windows If you create a cable using the cable wizard the group attributes are already correctly defined However if you are creating a cable manually you must also manually edit the group attributes of each conductor component phase neutrals or shields and verify that they follow the stated requirements Layer attributes do not affect the cable electrical properties They are only for facilitating cable editing operations For example in a multiphase cable it is WinIGS Training Guide Page 85 recommended to set all the parts of the phase A cable to Layer A all the parts of the phase B cable to Layer B etc This practice will allow you easily select all components of phase A together when you activate the Layer select option vertical toolbar button Layer This may be convenient if you want to reposition the concentric cables without moving the individual parts comprising each cable relative to each other Presently the Wizard supports only single core cables single phase Thus in order to define multicore cables the manual entry method i e the direct manipulation of various components must be used This process is obviou
173. r a short delay the plot illustrated in Figure 11 3 1s displayed Note that the impedance reaches a peak of 81 Ohms at 240 Hz i e the 4 harmonic in a 60 Hz system The implication of this result 1s that 1f a device connected between phase B and ground at BUS70 injects 1 Ampere at the 4th harmonic it will contribute 81 Volts at the 4 harmonic at the same location WinIGS Training Guide Page 207 Impedance Frequency Scan At 2 Node Port Figure 11 3 Impedance Frequency Scan Report Next the Trans Impedance analysis is demonstrated Click on the Analysis button select the Trans Impedance Transfer Function analysis mode and click on the Run button to open the TransImpedance Frequency Scan form This form is illustrated in Figure 11 4 Page 208 WinIGS Training Guide Transimpedance Transfer Function Close Injection Port 2 Node Port 3 Phase Bus Port BUS60 P O Positive Sequence ev V Negative Sequence 9 Zero Sequence Observation Port 2 Node Port 3 Phase Bus Port BUS80 P NA O Positive Sequence 4 Pa O Negative Sequence Zero Sequence Frequency Range 10 00 to 2100 00 Hz Number of Steps 100 e Transimpedance Transfer Function Execute STOP Analysis Completed Program WinlGS Form TSCAN PAR Figure 11 4 Trans Impedance Analysis Parameters Form Select the analysis parameters as illustrated in Figure 11 4 and click on the Execute button After
174. ransmission Line BUS10 to BUS Line to Line Circuit Length miles 9200 Faulted Phases Lines Fault Distance miles 4 600 E Phase A r Line L1 Measured From Bus BUS 10 r Phase B Faulted Circuit Number r Phase C D Line L2 c Short Circuit Between Two Nodes From Node To Node Figure 4 2 Fault Definition Form Once the fault analysis 1s completed click on the Reports button in order to view the V analysis results Click on the button to open the Single Line Diagram Report Selector form illustrated in Figure 4 3 Setup the bus voltage and through variable display fields as indicated in this Figure To modify these fields click on them and select the desired options from the pop up tables Click on the Accept button to close this form Copy Print Help Bus Voltage Displays IN Color Magnitude Neutral N PEE Result Display Font Size 90 00 Color Bus Name Font Size 20 pixels olor jus Name Font Angle 0 degrees Device Icon Size 0 100 Through Variable Displays Color Current Magnitude Neutral N E p Color m Iw am ll mnuai X q E BUS10 Color LIN Color Hide Bus Names r Hide Series Device Icons Hide Shunt Devices Hide Shunt Device Displays Figure 4 3 Single Line Diagram Reports Selector Form WinIGS Training Guide Page 153 When the Single Line Di
175. rements Delete All Measurements Mark Unmark Unmark All Um 20 00 40 00 60 00 80 00 100 0 Equivalent Separation Distance feet Probe Diameter 0 500 inches Algorithm Controls Default Probe Length 12 000 inches Distance Raw Meas No Correction Model Corrected Induced Voltage Correction C Real Part Only e Operating Frequency 72 00 Hz C Real Reactive Upper Rho 24374 Om Model Data Fit V I Lead Separation 20 00 feet View Corrected Data sadi ae C pl p2 A Layer Depth 15 85 ft Computations Completed Cpl Cp2 Ca I Objective 0 002316 Slayer ModelFit SoilModel STOP Process Sensitivity Figure 4 19 Wenner Method Data Entry amp Analysis Window With 2 bad data removed Page 48 WinIGS Training Guide Copy Print Help Wenner Method Soil Parameters Close Case Name IGS TGUIDE 01 Description Isolated Grounding System Example Grounding System Geometric Model Soil Resistivity Model Exp Value Tolerance zm Upper Soil Resistivity 243 7 Hm 5 8 Ohm Meters P Lom Lower Soil Resistivity 146 7 LE 28 Ohm Meters A y Upper Layer Thickness 15 8 T 0 9 feat At Confidence Level 90 0 Results are valid to depth of 150 0 feet Upper Soil Resistivity Lower Soil Resistivity Upper Layer Thickness L L L L 100m 1 L LI LI 20 00 40 00 60 00 80 00 100 0 20 00 40 00 60 00 80 00 100 0 0 00 20 00 40 00 60 00 80 00 100 0 Conf Level
176. rminal voltage with respect to which touch voltage is evaluated For example selecting the User Specified Group or Terminal radio button and then the MAIN GND entry from the pull down list box the touch voltage 1s computed as the voltage at every point within the plot frame minus the voltage of the MAIN GND conductor group Alternatively selecting the Nearest Grounding Point radio button option automatically selects as touch voltage reference the voltage at the nearest grounding system point Note that this option is not available for Model A analysis It is however the recommended option for models B C or D analysis since voltages vary along the lengths of the WinIGS Training Guide Page 61 conductors Touch Voltage Reference controls are effective only for touch voltage plotting Step Voltage Distance This field determines the method by which the step voltage is computed Specifically the step voltage is computed as the voltage difference between two points on the soil surface separated by this distance The IEEE standards define the step distance to be 3 feet The Step Voltage Distance control is effective only for step voltage plotting Equipotential Contour Controls These controls determine the resolution line density and distribution of the equipotential plot lines Equipotential plots are generated by first computing voltages on a uniformly spaced grid of points located within the plot frame The Resolution entry field sets the numb
177. s Once the inspections and modifications are completed save the study case and proceed to the analysis section Page 172 WinIGS Training Guide Three Phase Equivalent Circuit Accept Equivalent Circuit BUS50 to BUS70 Cancel Side 1 Bus Circuit Number Side 2 Bus BUS50 BUS70 115 0 kv 1215977007 c oc CUC 115 0 kV Base 100 MVA 1 Side 1 Side2 3 e Per Unit Ohms mMhos Ohms mMhos Percent 99 Positive Series Resistance 1 0000 Sequence Series Reactance 10 000 Shunt Conductance Shunt Susceptance Negative Series Resistance Sequence Series Reactance Shunt Conductance Copy Positive Shunt Susceptance Series Resistance 5 0000 50 000 0 00 Zero Sequence Series Reactance Shunt Conductance Shunt Susceptance 0 00 0 00 0 00 View Circuit Diagram Program WinlGS Form IGS M108 Figure 6 2 Equivalent Circuit Parameters Figure 6 3 Distribution Substation Grounding System WinIGS Training Guide Page 173 B6 2 Analysis It is recommended that a base case analysis is performed first in order to verify that the system model is consistent Click on the Analysis button and select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis is completed a pop up window appears indicating the completion of the analysis Click on the Close button to close this window and then c
178. s recommended to select the conductor size by first running a fault analysis at all voltage levels existing in the site under study including L N L L N as well as 3 Phase faults See Also Appendix 1 In this example we will use 4 0 Copper conductors e Avoid running conductors under or too close to equipment and building foundations e Place enough conductors so that everything will remain bonded together in the event that any single connector or conductor fails e Place a ground loop with vertical ground rods at all corners around sensitive electrical equipment and buildings typically power transformers and control houses This practice results in improved grounding system performance under transient conditions such as lightning strikes e Extend the ground mat to cover any areas where a perimeter fence gate may Swing over Click on the toolbar button ooo to open the insert electrode window Figure 4 8 Select the 2 row element titled Horizontal Ground Conductor ensure that the default layer is Ground Conductors and the default conductor type and size is Copper 4 0 then click on the Insert button Click and drag to insert horizontal conductors following the above rules As always to improve the conductor positioning accuracy zoom in and reposition the end points as necessary HINT Repeatedly creating the same element type can be accelerated using the F2 function key Furthermore a copy of a selected element can
179. s form computes the maximum allowable touch and step voltages according to either the IEEE Std 80 or the IEC 479 1 standard Editable parameters are Electric Shock duration default value of 0 250 seconds Standard Selection IEEE Std 80 or IEC 479 1 Body Weight 70 or 50 kg Applicable to IEEE Std 80 selection only Body Resistance See IEC479 1 Applicable to IEC 479 1 selection only Page 128 WinIGS Training Guide e Probability of Ventricular Fibrillation See IEC 479 1 Applicable to IEC selection only Reduction Factor IEEE Std80 2000 Edition Update Close Standard IEEE Std80 1986 Ref 1 see Help EEE Std80 2000 1 20 0 90 3 A Native Soil Upper Layer Resistivity LA T 2438 0 60 A Layer Resistivity J 2000 0 Reduction Factor Cs if Layer Thickness m 0 30 f 0 1000 k Factor 0 7827 0 00 _ Reduction Factor 0 00 0 050 0 100 0 15 0 20 0 25 0 7244 Layer Thickness meters Figure 1 22 Reduction Factor Computation Form Note that the fault current DC offset effect is automatically taken into account in the maximum allowable touch and step voltage computations However in this example fault data are not available since fault analysis was not performed base case analysis was selected In this example the maximum allowable touch voltage is 736 Volts and the maximum allowable step voltage 1s 2248 Volts Next click on the Close but
180. s indicates connection between neutrals at the corresponding buses Since the transformer delta tertiary bus has no neutral we must change the node name XF 3_N to XF 3_A as shown in Figure 3 15 to implement a grounding connector on the phase A terminal of the delta winding WinIGS Training Guide Page 23 a PI Copy Print Help TMITSCISASUISIT PTS Cancel Accept Delta Tertiary Corner Grounding Connector Side 1 Node Name Side 2 Node Name XF 3 A o o XF 1_N Circuit Number an Open o 01 Closed Show Title Figure 3 15 Entering an Autotransformer Model Next double click on the autotransformer icon to set up its parameters as given in Figure 2 1 The parameters specified in Figure 2 1 are repeated below for convenience Rated Power 280 MVA Voltages 230 kV 115 kV 13 8 kV L L Impedances P S 5 1 at 280 MVA P T 6 5 at 280 MVA S T 8 2 at 280 MVA The autotransformer parameters editing window with the above specified parameters 1s illustrated in Figure 3 17 Since the core parameters were not specified the default values of 0 005 PU for both nominal loss and magnetizing current are retained The last element we need to complete the integrated system model 1s the substation grounding model For this purpose we will use the Grounding System Geometric Model which allows for a detailed description of the physical grounding structures and facilitates safety analysis by means of t
181. s of the example system click on the Analysis button select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis 1s completed a pop up window appears indicating the completion of the analysis Click on the Close button to close this window and then click on the Reports button to enter into the report viewing mode B2 3 Inspection of Results While in Reports mode a set of radio buttons appears along the top of the main program window frame which allows selection of the report type The following options are available WinIGS Training Guide Page 135 Device Terminal Voltages and Currents Graphical I O Radio Button Device Terminal Real and Reactive Power Flows Power Radio Button Internal Device Voltages and Currents Internal I O Radio Button Voltages Currents and Power Flows at any Bus Multimeter Button Representative reports are illustrated in Figures 2 2 2 3 2 4 and 2 5 ere Copy Print Help Device Graphical V I Report Case DIAH 64 03 kV 0 01D 3 371 A 82 64D 64 03 kV 120 01D 3 130 A 42 80D 64 03 kV 120 00D 3 059 A 153 12D 114 8 mV 91 19D 10 97 mA 139 02D 114 8 mV 91 19D 43 84 mA 75 27D le 131 3 mA 91 19D Power Flow Analysis Example Transmission Line BUS10 to BUS30 Return 64 04 kV 0 01D 509 7 mA 147 77D 64 04 kV 120 01D 505 0 mA 27 76D 64 04 kV 119 99D
182. s purpose return to the Analysis mode and select the Maximum Ground Potential Rise analysis function and click on the Run button When the Maximum GPR or Worst Fault Condition form opens select the BUS30_N as the Maximum GPR Node and click on the Compute button When the analysis is completed the Maximum GPR analysis parameter form reappears indicating the worst fault condition as illustrated in Figure 7 4 WinIGS Training Guide Page 183 Maximum GPR or Worst Fault Condition Study Case Generation Substation Grounding System Design Maximum GPR at Node Faults Considered Maximum Distance From BUS30_N Selected Node co To Neutral To Ground 5 000 Mil Compute Both set to zero to consider all faults Worst Fault Condition Circuit Fault On Circuit 115 kV Transmission Line BUS40 to BUSG 1 Fault Type Line to Neutral Fault Fault Location 1 26 miles from bus BUS40 Max GPR kV 3 6497 X R Ratio at Fault Location 131431 Fault Current Magnitude kA Phase deg FAULTBUS A 12 6096 157 2514 ET 0 00 03 WinlGS Form WORST FL Copyright C A P Meliopoulos 1998 2004 Figure 7 4 Worst Fault Conditions The results indicate that the worst fault i e the one causing maximum GPR at BUS30 N is a line to neutral fault along the transmission line connecting BUS40 to BUS60 1 26 miles from the BUS40 terminal The GPR is 3 64 kV the fault current is 12 59 kA and the X R ratio at t
183. s results in a counter clockwise 90 degree turn Note that the delta tertiary of the transformer is not connected to any other part of the system However we must provide a path to ground for it otherwise the WinIGS solver will terminate with an error message In fact this 1s a general rule in creating models for win IGS Any part of any device must have a path to remote earth The simplest way to provide a path to remote earth for a delta tertiary is by connecting one node of the delta for example Phase A to the system neutrals For this purpose insert a 2 Node Connector model connect it from the delta winding terminal to the nearest bus that contains a neutral terminal Use the toolbar button command Insert Connector to open the connector selection window illustrated in Figure 3 15 Select the first entry titled Zwo Node Connector Model and click on he Accept button Then left click as necessary to define the connector path starting from node XF 3 and ending on node XF l as illustrated in Figure 3 16 b Copy Print Help Select Device Cancel Accept Description Two Node Connector Model Two Primary Bus Connector Model Two Secondary Bus Connector Model Two DC Bus Connector Model Figure 3 14 Entering an Autotransformer Model Next left double click on the connector icon to setup its parameters The connector parameters dialog is shown in Figure 3 15 By default both connector node names will be ending in _N Thi
184. sary to reduce the touch voltage below the maximum allowable value only in areas where grounded equipment is within reach Page 188 WinIGS Training Guide Figure 7 10 Touch Voltage 3 D Surface Plot for Worst Fault Conditions At this point you are encouraged to return to edit mode and enhance the system in order to improve its safety performance Enhancements may involve adding grounding conductors in the substation grounding system or enhancing the grounding of the transmission lines reaching the substation Next repeat the presented analysis procedure to evaluate the enhanced system performance Note that it may be necessary to repeat this analysis enhancement cycle several times before an acceptable safety performance 1s achieved WinIGS Training Guide Page 189 Appendix B8 Stray Current Analysis and Control This section illustrates the application of the WinIGS program to the computation of stray currents and voltages and the analysis of mitigation techniques The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH08 The single line diagram of the example system 1s illustrated in Figure 8 1 Step by step instructions lead the user through opening the case data files viewing the system data running the analysis and inspecting the results 3 Ph Eq Cid BUSTO B D e Equiv Source Equiv Source Figure 8 1 Single Line Diagram of Example System IGS_
185. scheme of the substation as shown in Figure 3 10 Note that the connector models representing the substation breakers include optional Neutral and Ground Conductor Connectors By default the Neutral Connectors are activated as illustrated in the connector parameters window See Figure 3 11 In this configuration these connectors bond together the transmission line ground conductors This can be also verified using the Bus Connection Inspection Window illustrated in Figure 3 12 This window is opened by left double clicking on any bus node The buss connections shown in Figure 3 12 are for the bus SUBIO Note that the 115 kV Transmission Line has two terminals terminating on the vertical blue line representing the neutral These terminals represent the two shield wires of the line Page 20 WinIGS Training Guide i Figure 3 10 Network View after addition of Substation Breakers x lt e Copy Print Help Primary Bus Connector me Accept 115 kV Breaker 2 Cancel Bus Name Bus Name SUB30 SUB10 Figure 3 11 Connector Parameters Window WinIGS Training Guide Page 21 115 kV Breaker 1 115 kV Line fo Bus 10 115 kV Breaker 2 Figure 3 12 Bus Connection Inspection Window Next enter the Auto Transformer model Use the toolbar button Li command Insert Multiterminal to open the multi terminal element selection window illustrated in Figure 3 13 Select the fourth entry titled Autotransformer wi
186. se two parameters along with the radio button setting Equal Current Steps Equal Stroke Distance Steps determine the number and values of the lightning crest values considered in the analysis The default values are recommended for most practical systems You may increase the Number of Current Striking Distance Steps for higher accuracy at the expense of longer execution time Once the desired parameters are selected close this form by clicking on the Accept button and click on the EGM toolbar button to initiate the LSA computations While LSA analysis is in progress the lightning strikes considered in the analysis are displayed graphically as illustrated in Figures A4 6 and A4 7 WinIGS Training Guide Page 101 Lightning Model Options Cancel Accept Striking Distance Options Striking Distance versus Crest Value Brown and Whitehead 1969 1000 IEEE 1985 Eriksson 750 Darveniza E Love Suzuki et al O Rizk m z a MI crest vau ka a D Striking Distance ft 0 004 Na 0 00 40 00 80 00 120 0 160 0 200 0 Striking Distance Shape Factor Lightning Crest Value kA Lightning Crest Rise Time Crest Value Historical EPRI Red Book 1 00 2 State of Georgia 3 Ashville Area S9 ov 4 Anderson IEEE m 5 Mousa IEEE 6 Tracy CC Plant 1997 2006 9 0 50 E 3i Crest Value E 0 25 O Rise Time a ENS oii e robability 0 00 40 00 80 00 120 0 160 0 200 0 4 AU M
187. sidered WinIGS provides rectangular and polygonal plot frame elements which define the region where touch and step voltages are to be evaluated The toolbar buttons for inserting rectangular and a polygonal plot frames are identified in Figure 5 13 The red line enclosing the substation perimeter is a typical example of a polygonal plot frame defining the touch voltage computation area This line has been accurately positioned 3 feet outside the perimeter fence so that touch voltages for persons standing outside the fence can be evaluated Left Double clicking on the polygonal frame outline opens a dialog window shown in Figure 5 14 on which equipotential plotting parameters are specified WinIGS Training Guide Page 59 Page 60 a a File Edit Select View Insert Transformations Tools Window Help a a Equipotential Plots Edit Analysis R do z bokr npPBoa x 57 13 y2 7 72 m Update Retum 3D Plot STOP C Earth Voltage Touch Voltage P El your Reports Tools Polyline E quipotential Plot Frame C StepVoltage Conductor Voltage EN EEENEN GANG VERDUNEX GERDNANC ONE S E UEM NE CENE GE Grid Spacing 1000 0 m A ModelA B C D E ii N MAN GND I Polygon Defining Touch Voltage Computation Area F G H Control House all a 400 f gt K Sut Subs ES L Equipme August 26 2014 0 15 0 45 e Advanced Grou 1 2 3
188. sly a bit more complicated It requires that certain rules are followed in order to end up with a properly behaving cable model Most importantly the conductor and neutral GROUP attributes must be assigned consecutive distinct numbers as shown in the example below Neutral Conductor Phase Conductor A Group 2 Group 1 Layer A Layer A Neutral Conductor Neutral Conductor hes Group 4 d Layer B d x E b V N r4 Phase Conductor Phase Conductor Group 5 Group 3 Layer C Layer B Figure A1 10 Example Group Assignment for a Three Phase Cable This group numbering will result in the correct operation of the automatic node assignment when using cable models within a power system model For example the above group numbering will result in the node assignment shown below Page 86 WinIGS Training Guide Copy Print Help Node Assignment Cancel Accept Circuit Side 1 Side 2 Auto Assign Phases CKT1 NEWBUS1 A NEWBUS2 A CKT1 NEWBUS1_N NEWBUS2_N CKT1 NEWBUS1 B NEWBUS2 B CKT1 NEWBUS1 N NEWBUS2 N CKT1 NEWBUS1 C NEWBUS2 C CKT1 NEWBUS1 N NEWBUS2 N Lx c Ool NIONA Oo PO h mii m me ml m m m mh m 00 NI OD O91 I PO O N o Figure A1 11 Node Assignment for a Three Phase Cable One possible way to go about creating a multicore cable such as the one shown above 1s to start with the wizard to create the components for one phase and use cop
189. smission Line model This model is capable of representing any number of conductors in any arrangement including coupled circuits terminating in different buses Double click on the BUS40 to BUS60 line diagram to open the parameters form illustrated in Figure 10 2 Note that conductor 5 represents a communications circuit It is bonded to the neutral at BUS40 and feeds a communications load at node COMMCIR 100kQ resistor You can also view a graphical representation of the conductor WinIGS Training Guide Page 201 arrangement by clicking on the View Configuration button which is illustrated in Figure 10 3 The communications conductor in that Figure is labeled N2 Generalized Transmission Line Model Cancel Accept Mutually Coupled Multi Phase Lines View Configuration Conductors Copy Delete FromNode ToNode Circuit Cond Size Sub Sep Gnd 1 BUS40A BUS60 A CKT1 ACSR ORIOLE 1 0 NO 00 380 2 BUS40B BUS60 B CKT1 ACSR ORIOLE 1 O NO 1 75 36 0 3 BUS40 C BUS60 C CKT1 ACSR OROLE 1 0 NO 175 36 0 4 BUS40 N BUS60 N CKT1 ACSR WAXWING 1 0 YES 00 300 5 BUS40_N COMMCIR N CKT2 COPPER 14 1 0 NO 0 0 25 0 Circuits Copy Delete Name Span GrH Gr X OpV kV FOW kvV BIL kV AC kV TrPh TrSh Shid 1 CKT1 0 075 500 0 0 12 0 375 0 285 0 95 0 NO NO BND 2 CKT2 0 075 50 0 0 0 0 048 1 0 0 9 0 7 NO NO BND Line Length miles 25 Soil Resistivity ohm meters 100 0 Circuit Number 1 Program WinlGS Form IGS M109 F
190. ssion Line Voltage amp Current Profile Close Distribution Line 12 kV BUS40 to BUS60 Displayed Quantity Voltage Reference Nominal Voltage Plot Mode Voltage Remote Earth Absolute Current Neutral 12 00 ER c Deviation Ground 10 0 Distance _A pM A B Ei 5 00 S E 2 50 A _N B N 0 00 I l l I I 0 00 0 75 1 50 2 25 3 00 3 75 BUS40 Distance miles BUS60 Figure 3 9 Voltages along BUS40 to BUS60 Distribution Line during a Phase B to neutral fault at BUS30 Page 146 WinIGS Training Guide Three phase fault Perform this analysis for a three phase fault along transmission line BUSIO to BUS30 4 miles from BUSIO and as directed in the Analysis section Once the analysis is completed click on the Reports button to view the analysis results The phase voltage and currents magnitudes can now be seen on the single line diagram as illustrated in Figure 3 10 Va 2755kV Vb 2940 amp V Yc 2974kV Va 56 19 kV Vb 56 97 kV h 7018A lh 7018A Va 265 WV Ib 7024A o 704A Vb 2672kV Y 7247 1c 7248 A N Vc 2758 kV Va 2748 kV LE ie Y Vb 2 738 kV We 2 845 kV Custom er 1 Ia 14 59 A Ib 1455 A Ya 2725kV Ic 15 07 A Ic 15 09 A YVb 2717 amp kV Customer 2 Figure 3 10 Single Line Diagram Indicating bus voltages and current flows 3 Phase fault along BUS10 to BUS30 Transmission Line As in the previous example you can examine the voltage and curren
191. st Users Datall Doc ice IGS_AGUIDE_CHO1 lice IGS_AGUIDE_CHO2 lice IGS_AGUIDE_CHOS lice IG5_4GUIDE_CHO4 3 IG5_AGUIDE_CHOS lize IGS AGLIDE CHUB lic IGS_AGUIDE_CHOB_ lize IGS_AGUIDE_CHO 3 laS AGLUIDE CHUS lice IG5_AGUIDE_CHOS lize IGS_AGUIDE_CH10 lic IGS_AGUIDE_CH11 lice IGS_AGUIDE_CH12 3 laS AGUIDE CHT3 lice IGS_A4GUIDE_CH14 OF 227 2014 12 16 2012 08 21 2011 08 17720 4 10 25 2011 O22 02 2013 03 21 2011 03 20 2011 05 04 2011 0771972013 10 26 2011 08 04 2011 10 26 2011 05 04 2011 05 04 2011 OF 12 201 2 18 42 16 18 54 00 18 41 20 16 53 26 10 22 40 22 21 58 01 25 44 15 02 46 12 38 52 14 25 58 10 40 18 12 39 18 11 47 14 12 35 54 12 40 04 17 55 42 Isolated Grounding System Example Power Flow Analysis Example Short Circuit Analysis Example System Ground Potential Hize Computations Example System Distribution Substation Grounding System Design Transmission Substation Grounding System Design Transmission Substation Grounding System Design Generation Substation Grounding System Design Stray Current Analysis and Control Example System Transmission Line Sequence Parameter Computations Induced Transferred Voltage Computations Harmonic Propagation Computations Lightning Shielding Analysis Example Cathodic Protection Analysis Example Example 14 Wind Farm System Four Turbine 1 5 MYA Generator System Apolication Example 15 Utility size PY Farm lic IGS_
192. stance From WTU1 TWR N Selected Node guo Neuttel 0 000 Mil O To Ground Compute e Both set to zero to consider all faults Worst Fault Condition Ssmus Fault On Circuit Fault Type Fault Location Max GPR kV X R Ratio at Fault Location Fault Current Magnitude kA Phase deg ee eee Figure 13 5 User Interface Form for Selecting maximum GPR Analysis Click on the Compute button The program will perform a fault analysis search to determine which fault will create the highest ground potential rise at node WTUI TWR_N which is the ground node of the Wind Turbine One Once the analysis is completed a pop up window appears indicating the completion of the analysis and reports the maximum GPR at this node The report is shown in Figure 13 6 WinIGS Training Guide Page 221 Maximum GPR or Worst Fault Condition Study Case Example 14 Wind Farm System Four Turbine 1 5 MVA C Maximum GPR at Node Faults Considered Maximum Distance From WTU1 TWR N Selected Node gato Neuttel 0 000 Miles O To Ground Compute e Both set to zero to consider all faults Worst Fault Condition Ssmus Fault On Circuit Distribution Line 34 5 kV To Wind Farm 1 FaultTypelLinetoNeutralFaut Fault Location 0 06 miles from bus WTU1 XH MaxGPR kV 28055 X R Ratio at Fault Location 2 2524 Fault Current Magnitude KA Phase deg FAULTBUS A 4 7468 65 4243 ET 0 00 06 Figur
193. t common cable editing operations A description of the toolbar button functions is given in the table A1 1 below Table A1 1 Vertical Toolbar Button Functions Button Description Save present cable configuration into cable library Opens the general cable editor options dialog General options include Metric English unit selection snapping interval and options to draw or suppress the view axes and scale legend Copy selected elements into windows clipboard Paste elements from windows clipboard into the cable editor view Copy selected elements into windows clipboard then delete these elements from the cable editor view Undo last editing operation Re apply last undone editing operation odo X mg Open General Cable Parameters Dialog Window Same as double clicking on the legend area located on the right side of the editor view window a Inserts a cable component Opens the dialog window with a list of available component types Click on the desired type and then on the Insert button to insert a component into the editor view e Move selected components in front of all other components Move selected components in behind all other components ge Open cable Wizard Window This tool automatically creates cable components based on user selected geometric and material parameters Imports the components of an existing cable in the cable library into the working editor view Opens a list of existing cable from
194. t reports of any system component of interest or view the voltage and current distribution along any selected circuit Figure 3 11 illustrates the voltage profile along the transmission line from BUSIO to BUS30 Note the voltage variation along the phase wires due to the 3 phase fault at 4 miles from BUSIO Similarly Figure 3 12 illustrates the voltage profile along the transmission line from BUS30 to BUS20 WinIGS Training Guide Page 147 Scr LI Li Li Y Transmission Line Voltage amp Current Profile Close Transmission Line BUS10 to BUS30 Displayed Quantity Voltage Reference Nominal Voltage Plot Mode Voltage Remote Earth Absolute Current Neutral 115 00 Ed Deviation Ground Distance _A 22 5 _B 15 0 S 7 50 A 50 75 N N 0 00 I N l i I I I _N 0 00 2 00 4 00 6 00 8 00 10 0 BUS10 Distance miles BUS30 Figure 3 11 Voltages and Currents along BUS10 to BUS30 Transmission Line during a 3 Phase fault along BUS10 to BUS30 Transmission Line a Transmission Line Voltage amp Current Profile Close Transmission Line BUS30 to BUS20 Displayed Quantity Voltage Reference Nominal Voltage Plot Mode Voltage Remote Earth Absolute c Current Neutral ER xil eres Deviation Ground 60 0 Distance Voltage kV S amp e e m l C 15 0 N 0 00 I I l _N 0 2 00 4 00 6 00 8 00 10 0 BUS30 Dis
195. tance miles BUS20 Figure 3 12 Voltages and Currents along BUS30 to BUS20 Transmission Line during a 3 Phase fault along BUS10 to BUS30 Transmission Line Page 148 WinIGS Training Guide Short Circuit Between two Nodes Perform this analysis for the short circuit between high side and low side phase A of the substation transformer BUS30 A to BUS40_A and as directed in the Analysis section Once the analysis is completed click on the Reports button to view the analysis results The phase voltage and currents magnitudes can now be seen on the single line diagram as illustrated in Figure 3 13 Va 54 68 kV Vb 63 41 kV Va 5815 kV c 7021 kV Vb 63 91 kV Y EOI 9 Y 1608 91 Ic 1196 A o 420 kV Ia 3265 A Va 1208 kV Ib 1626 YVb 6 731 KV BUS60 Custom er 1 la 68 63 A Ih 32 63 A Va 12 39 kV Ic 2553 A Ic 25 64 A Customer 2 Figure 3 13 Single Line Diagram Indicating Bus Voltages and Currents Flows during Fault between Transformer High and Low Voltage Phase A Terminals BUS30_A and BUSAO A Again you are encouraged to examine the voltage and current reports of any system component of interest or view the voltage and current distribution along any selected circuit You can also see the voltage and current phasors at any desired point using the Multimeter tool Figures 3 14 and 3 15 illustrate the voltage and current phasors at the high side and low side transformer terminals respectiv
196. ted Circuit Line to Ground C Line to Line Circuit Length miles Faulted Phases Lines Fault Distance miles 4 600 A Phase A r Line L1 Measured From Bus 7 Phase B Faulted Circuit Number Phase C C Line L2 c Short Circuit Between Two Nodes From Node To Node Figure 3 3 Fault Definition Form Fault location can be a at any system bus b along any circuit and c between any two nodes of the system Fault types can be 3 phase Line to Line to Neutral Line to Line To Ground etc Faults can be applied to any combination of phases as long as the fault type is consistent with the number of faulted phases specified Note that fault type and faulted phases entries are ignored if the Short Circuit Between Two Nodes option is selected Note also that a distinction is made between neutral and ground wires or nodes Again the fault specification must be consistent with the construction of the device or bus that the fault is applied to For example if a bus has phases A B C and N faults to this bus can only be specified between any number of phases and neutral Specifying a Line to Ground fault will result in an error message since there 1s no ground node on that bus Once all the desired selections are made click on the Execute button to perform the analysis B3 3 Inspection of Results The results of three fault analyses are presented in this section a Phase B to neutral fault at BUS3
197. ted at the left side of this page Click on the Ss button to open the LSA parameter setup form illustrated in Figure 12 5 The following parameters can be selected Striking Distance versus Lightning Current Crest Value Function One of seven tabulated such functions are selectable via corresponding radio buttons Lightning Crest and Rise Time Probability Distribution Function One of five tabulated function sets is selectable via corresponding radio buttons Layer Striking Distance Shape Factor If this box is checked the shape of the stricken objects affects the striking distance computation Specifically the striking distance for tall vertical objects such as lightning masts and air terminals is 1 2 times longer than for other objects such as buildings and horizontal shield wires Sky Grid Size and Maximum Sky Grid Size These parameters determines the resolution of the sky area where lightning strikes can originate The Sky Grid Size is a percentage of the striking distance Thus the actual sky grid size increases as higher crest values and thus striking distances are analyzed unless it exceeds the Maximum Sky Grid Size specified value The sky grid size greatly affects the computation time For example for a 500 by 500 foot site a grid size of 2 meters results in a grid of about 6000 points while a value of 1 meter results in a grid of about 24 000 points Minimum Stroke Current and Number of Current Striking Distance Steps The
198. tential rise is 6 666 kV Copy Print Hel Device Graphical V I Report Case Isolated Grounding System Example Device Example Grounding System Return 6 666 kV 0 00D 6 500 kA 0 00D Remote Earth 6 500 kA 0 00D Figure 1 20 Grounding System Voltage and Current Report Next click on the Return button to close the grounding system voltage and current report select the Grounding Reports radio button and double click on the grounding system icon This action opens the grounding system viewing window and provides a selection of several grounding system specific reports namely a Grounding Resistance Reports b Correction Factor c Safety Criteria and d Touch and Step Voltage Profiles Note that this environment is similar to the ground editor Specifically the grounding system can be viewed in top view side view perspective view zoomed panned rotated etc However grounding geometry and ground conductor parameters cannot be modified System data modifications are allowed only in Edit mode Click on the Grounding Resistance button to view the Grounding system resistance report This report is illustrated in Figure 1 21 Note that the resistance of this system is 1 0256 ohms WinIGS Training Guide Page 127 Copy Print Help Ground System Resistance Report Study Case Title Isolated Grounding System Example Grounding System Example Grounding System R
199. th Tertiary 3 Phase and click on he Accept button Click in the area between the 115 and 230 kV breakers to insert the autotransformer icon Copy Print Help select Device Cancel Accept Description Substation Model Transformer 2 Winding 3 Phase Transformer 3 Winding 3 Phase AutoTransformer without Tertiary 3 Phase Transformer with Secondary Centertap Single Phase Transformer 3 Phase Sequence Par Grounding System Geometric Model Generalized Conductance Matrix Model AC DC Converter 3 Phase Transformer 4 Winding 3 Phase Transformer Two Winding Single Phase Transformer 3 Winding Single Phase Autotransformer without Tertiary Single Phase Autotransformer with Tertiary Single Phase Delta ZigZag Transformer Paracitic Cap Saturable Core Transformer with Secondary Centertap Single Phase SF Qo o 00 WHY Figure 3 13 Multi terminal Element Selection Window Page 22 WinIGS Training Guide The auto transformer icon will appear as shown ion Figure 3 16 a Note that the icon has three terminals corresponding to the primary secondary and tertiary windings Next connect the terminals to the appropriate nodes by left clicking on each terminal end point and moving it to the appropriate bus Specifically move the secondary terminal to bus XF 1 and the primary terminal to bus XF 2 In order to improve the diagram appearance you can rotate the icon by selecting it and pressing the R key Each key pres
200. the existing line and the substation The resulting model single line diagram is illustrated in Figure 6 2 Note that the parameters of the added mutually coupled multiphase line model must be matched with the parameters of the existing line model same conductor types and sizes identical tower pole configuration same tower ground resistance etc A shortcut in creating such a model is provided by the Model Conversion command of the Tools pull down menu This command is also accessible via the toolbar button Ar The procedure for using this command is as follows 1 Create a copy of the transmission line model to which the counterpoise ground will be added Line to bus 10 in this example Use copy and paste to achieve this 2 Select the created transmission line copy left click on line diagram with mouse Execute the Model Conversion command 4 On the Model Conversion dialog window check the option Convert Overhead Line Model to Mutually Coupled Multiphase Line Model See Also Figure 6 3 Select Option Apply to Selected Devices Only and click on the Convert Button 6 Position the created line model in cascade with the existing line and connect it to the substation under study as illustrated in Figure 6 2 p p Page 68 WinIGS Training Guide 10 BUS20 Substation X EEE ar EET ERR ae RESI RE ES Grounding Model vie BUS30 BUS40 Figure 6 1 Example Network Model Now edit the parameters of the co
201. tion it was concluded that the example system does not meet the IEEE Std 80 safety requirements because the maximum touch voltage occurring during the worst fault conditions exceeds the permissible value In this section grounding enhancements for the purpose of reducing touch voltages are modeled and evaluated Two approaches are presented a grounding enhancement of the transmission lines that terminate to the substation under study and b direct enhancement of the substation erounding system Note that the first approach has the added advantage of also reducing the ground potential rise while the second approach affects the GPR very little 6 1 Adding a Transmission Line Counterpoise Ground Consider the network model of the example system illustrated in Figure 6 1 The substation under study is fed by four transmission lines One very effective method to reduce GPR is to add a counterpoise ground conductor along the path of a transmission line and bond the counterpoise ground to the line poles and to the substation grounding system In order to model this scheme in WinIGS the simple overhead transmission line model is replaced by a mutually coupled multiphase line model which 1s capable of representing counterpoise grounds The counterpoise ground will be located along the two line spans nearest to the substation Thus the existing line model is made shorter by 2 spans 0 16 miles in this example and the added line model is added between
202. to the rendered 3 D mode view to obtain the system 3 D view shown in Figure A4 3 Note that in addition to grounding electrodes the model includes 3 D representations of major equipment and civil structures Specifically the model includes transformers switchgear bus work shielding poles and a control house Page 98 WinIGS Training Guide Figure A4 2 Single Line Diagram of Example System IGS AGUIDE CH12 Lightning shielding analysis requires 3 D geometric data of electrical equipment and civil structures Once the geometric data entry is completed it is recommended that all components are assigned to appropriate layers in order to facilitate LSA report generation For example in order to generate a report of lightning statistics on all phase Wires it is recommended to create a phase conductor layer and set all components representing phase conductors to that layer Figure A4 3 shows the layer setup in the example system Figure A4 4 shows the parameter form for a phase conductor model Note the layer field is set to phase conductors see also Layers topics in WinIGS users manual Layers Command and Layers Selection Mode WinIGS Training Guide Page 99 Ground System Editor Layers Cancel Accept Bare drew ese coor I I e mu EN renes Foundations _es s s s s C _ Control Building Bus Phase Conductors Rigid ts Line Phase Conductors Flexible
203. ton of the Safety Criteria form and then on the Equipotential Plot and Safety Analysis button Note that the program upper toolbar changes to display the Equipotential plot controls In order to view the touch voltage distribution the area of interest must first be defined The area of interest is defined by a plot frame object A plot frame object has already been defined in this example It is identified by a light gray rectangle circumscribing the erounding system aligned with the outermost ground conductor loop Note that the plot object can be resized moved and rotated using the mouse Further more additional parameters associated with plot frames can be edited by opening the plot frame parameter form illustrated in Figure 1 24 WinIGS Training Guide Page 129 Copy Print Help Safety Criteria IEEE Std80 2000 Edition Close Electric Shock Duration 0 250 seconds View Plot Permissible Body Current 0 232 Amperes IEEE Std80 2000 Body Weight 70kg 50kg Probability of Ventricular Fibrillation 0 5 c IEC Body Resistance 5 C50 C959 Probability of Ventricular Fibrillation c 0 14 05 5 DC Offset Effect Fault Type N A X R Ratio 0 0000 Faulted Bus N A Decrement Factor 1 0000 Permissible Touch Voltage Over Insulating Surface Layer 736 2 V Q Over Native Soil 316 8 V C Hand To Hand Metal to Metal 232 0V Permissible Step Voltage Select 1 v O
204. tors _ 230 kV Transmission Line Phase Conductors Shiled Wires Communications Tower Pavement Line End Structures 7 V SRiegW auae r N m JEN E i 5 D i UT HERRERA PRRERRRRERREEE L uu ua e E 3 Ur Figure A2 3 List of Example System Layers and Color Codes WinIGS Training Guide Page 91 In order to avoid unnecessary violation reports elements of equipment models representing insulators should be appropriately set Specifically the insulator check box in the parameters window of cylinder objects representing insulators should be checked See example below Lock Accept 230 kV Phase A Insulator Bushing Cancel All Dimensions in Feet Top Radius Bottom Radius Center X Coordinate Center Y Coordinate Bottom Z Coordinate Height Layer Structural Group Total Mass i z y 5 061 T3 a z 35344 HI amp t 19 000 ur 6 000 0 500 0 750 Electrical Equipment NON SDA 100 000 kg Update Ix ly Iz Moments kg m 27 684 27 684 1 934 Order Angle Deg Axis Base to Center of Mass Enable 1 Rotations 2 Lali Lightning Mast x 2 605 Yi Zz Page 92 Check if this object represents a lightning pole 7 Insulator Check if this object represents an Insulator Figure A2 4 Setting Insulator Attribute in Cylinder Object The clearance analysis function is accessed usin
205. trode window shown in Figure 4 8 Select the 4 row element titled Fence Post Array then click on the Insert button Next sequentially left click on the fence corners as shown on the background drawing and terminate the fence entry mode by clicking the right mouse button Note that this operation is similar to the transmission line element entry method described in the Network Editor Section Section 3 To improve the fence positioning accuracy zoom in and reposition the fence segments as necessary by clicking and dragging the fence corner points Note that you can also add or remove selected corner t points using the toolbar buttons and respectively Next left double click on the fence outline to open the fence parameters window illustrated in Figure 4 9 Note that in addition to the fence corner coordinates editable fence parameters include the fence post length the fence post burial depth the fence post type and size the fence post spacing the Group name and the Layer of the fence model Note also that the fence has the default group name MAIN GND which means that the fence will be assumed to be electrically bonded to the grounding system Click the Accept button to close this window Page 36 WinIGS Training Guide E Copy Print Help Double Click on Element to be Inserted Rectangular Ground Mat Horizontal Ground Conductor Single Ground Rod Ground Rod Array Non Uniform Ground Mat Steel Re Bar Concret
206. ty Criteria computation form illustrated in Figure 7 8 Note that the maximum allowable touch voltage according to IEEE Std 80 for a 0 25 second shock duration and a 50 kg person is reported to be 732 Volts Note also that the computation of the maximum allowable touch voltage has taken into account the X R ratio at the fault location X R 1 3078 Page 186 WinIGS Training Guide Safety Criteria IEEE Std80 2000 Edition Close Electric Shock Duration 0 250 seconds View Plot Permissible Body Current 0 232 Amperes IEEE Std80 2000 Body Weight O 70kg 50kg Probability of Ventricular Fibrillation 0 5 O IEC Body Resistance 5 O 50 O 95 Probability of Ventricular Fibrillation O 0 14 0 5 O 5 Touch Voltage 732 0 Volts Hand to Feet feet on soil Step Voltage 2237 0 Volts O Hand to Hand metal to metal DC Offset Effect Fault Type Circuit Fault X R Ratio 1 3141 Faulted Bus FAULTBUS Decrement Factor 1 0069 WinlGS Form GRD RP03 Copyright C A P Meliopoulos 1998 2004 Figure 7 8 Safety Criteria Report Form To plot the touch voltage distribution click on the Equipotential and Safety Assessment button Note that a polygonal plot frame has already been defined gray frame along the perimeter of the station Click on the Update button to obtain the touch voltage equipotential plot which is illustrated in Figure 7 9 Note that the maximum touch volt
207. uctor ICOPPER 4 0 Figure 4 3 Reference Object Selection Window Next left click and while holding the mouse button down drag the mouse to define the rectangular region for the drawing Next double click on the default image Rusty the Cat to open the image file parameters window shown in Figure 4 4 Click on the directory path field titled File to open a standard Windows directory navigation dialog Navigate to the provided drawing file titled gnd_drawing jpg select it in click on the Open button For better image quality click on the Halftone Color radio button located in the Rendering Group In order to easily distinguish the background image from the model objects to be placed on top of the image click on the radio button titled Blue located in the Color Shift group and set the brightness level to 100 Next click on the Apply button then on the OK button Next we will resize the drawing so that it is correctly scaled This procedure is facilitated using the Reference Segment tool Refer to Figure 4 5 a Initially the reference segment is of zero length and coincides with the image lower right corner see red arrow in Figure 4 5 a Left click and drag the reference segment end points from the initial location so that the reference segment is superimposed over a line of known length such as a drawing dimensioning line as illustrated in Figure 4 5 b Page 32 WinIGS Training Guide Copy Print Help Ima
208. unding System Design Maximum GPR at Node Faults Considered Maximum Distance From SUB1_N Selected Node SOR Neural C To Ground Compute 5 000 Miles Hes set to zero to consider all faults Worst Fault Condition Circuit Fault On Circuit Fault Type Fault Location Max GPR kV XIR Ratio at Fault Location Fault Current Magnitude kA Phase deg Figure 5 4 Maximum GPR analysis parameters form During the maximum GPR analysis the program performs a sequence of fault analyses while monitoring the GPR at the selected Maximum GPR Node Faults are placed sequentially along all circuits and at all buses Both SLN and LLN faults are analyzed When the analysis 1s completed the Maximum GPR analysis parameter form reappears indicating the worst fault condition as illustrated in Figure 5 5 Page 160 WinIGS Training Guide O x Copy Print Help Maximum GPR or Worst Fault Conditior Close Study Case Distribution Substation Grounding System Design Maximum GPR at Node Faults Considered SUB1 N M AMA e um Toner To Ground Compute ET Mies IRE set to zero to consider all faults Worst Fault Condition Circuit FaultOnCircuit WA NA Fault Type Line to Neutral Faut Fault Location SUBl Max GPR kV 6785 XIR Ratio at Fault Location 3 6655 Fault Current Magnitude kA Phase deg SUB1 A 6 8951 4 7688
209. unt the X R ratio at the fault location X R 7 7 Safety Criteria IEEE Std80 2000 Edition Close Electric Shock Duration 0 250 seconds View Plot Permissible Body Current 0 232 Amperes IEEE Std80 2000 Body Weight O 70kg 50kg Probability of Ventricular Fibrillation 0 5 O IEC Body Resistance 5 O 50 O 95 Probability of Ventricular Fibrillation O 0 14 0 5 O 5 Touch Voltage 721 6 Volts Hand to Feet feet on soil Step Voltage 2218 3 Volts O Hand to Hand metal to metal DC Offset Effect Fault Type Bus Fault X R Ratio 8 0319 Faulted Bus BUS30 Decrement Factor 1 0417 WinlGS Form GRD RP03 Copyright C A P Meliopoulos 1998 2004 Figure 6 9 Safety Criteria Report Form The next step is to plot the touch voltage distribution and compare the results to the maximum allowable touch voltage value Click on the Equipotential and Safety Assessment button Note that a polygonal plot frame has been defined gray frame along the perimeter of the substation Click on the Update button to obtain the touch voltage equipotential plot which is illustrated in Figure 6 10 Note that the maximum touch voltage occurs near the center of the upper right mesh of the substation grounding system The actual maximum touch voltage value is 850 Volts while the maximum allowable touch voltage 1s 723 Volts Page 178 WinIGS Training Guide 1 Grid Spacing 100 0 ft
210. usage of this feature by means of an example Figure A2 1 shows a 3 D rendered view of the example system It is a detailed model of typical transmission substation which includes models of bus conductors overhead line conductors bus supporting structures buildings light poles antennas and other various outdoor electrical equipment The model elements have been organized in a number of layers For the purposes of this application it is important to place phase conductors of different nominal voltage levels in different layers This will allow associating appropriate clearance limits to conductors according to their nominal voltage levels The layer organization is illustrated in Figures A2 2 and A2 3 W ye N N NA 3 r3 As b N N r N i od N o 1 1 M LN t t 5 5 Y i ES lt N k Hl gt b i E ih DE E du E m lt lt J k D M ee B aN NONUNSN MES s i OSEE SINN CHE EN NRA A P OMM E SIN id ed MY Ll Lour Figure A2 1 3 D Rendered View of Example System Page 90 WinIGS Training Guide 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 18 17 18 19 20 21 22 23 24 25 26 Grid tue ne eee A Freque A Figure A2 2 View of Example System with Color Coded Layers m Ground Conductors mE Fence Foundations Foundation Rebar Electrical Equipment Bus Supports Buildings 115 kV Bus Phase Conductors 230 kV Bus Phase Conductors 115 KV Transmission Line Phase Conduc
211. ver Insulating Surface Layer 2248 7 V Over Native Soil 571 3 V C Figure 1 23 Safety Criteria Form Double click on the plot frame perimeter to open the plot frame parameter form The plot frame parameters include Page 130 The x y coordinates of two diagonally opposite frame corners This data determine the size and location of the plot frame The rotation angle which determines the plot frame orientation The number of points which determines the resolution of the Equipotential plots Specifically increasing this number results in higher resolution plots but also increases the required computation time The Step Distance This parameter is applicable only to step voltage computation The standard step distance value per IEEE Std 80 is 3 feet WinIGS Training Guide e The Reference Group or Terminal This parameter is applicable only to touch voltage computations The touch voltage is computed as the difference between the voltage at a point on the soil surface and the voltage on the selected group or terminal In this example the entire grounding system is one group MAIN_GND and there is only one terminal GRSYS_N thus there is only one possible selection However in a multi terminal grounding system it is important to select the correct reference group See also the WinIGS Program users manual for more information on this topic r n E Copy Print Help Voltage Plot Polygonal Fra
212. vice Terminal Multimeter Case Short Circuit Analysis Example System Device Power Transformer 115kV 12kV 20MVA Side 1 Side 2 3 Phase Power Voltage EE L G Phase Quantities Per Phase Power Current c L L Symmetric Comp Impedance Voltages Van 11 72 kV 9 608 Deg BUS40 A Vbn 5 143 kV 145 8 Deg Ven 6 872 kV 90 29 Deg BUS40 B Ven la 12 27 KA 71 50 Deg e Ib 195 2 A 47 21 Deg BUS40 C Ic 144 8 A 101 8 Deg BUS40_N Currents b 3 BUS40 A e BUS40 B 6 e BUS40 C e Figure 3 15 Transformer Secondary Terminal Voltages and Currents during Fault between Transformer High and Low Voltage Phase A Terminals BUS30_A and BUSAO A Page 150 WinIGS Training Guide Appendix B4 Ground Potential Rise Computations This section illustrates the ground potential rise computations using the WinIGS program The presentation is based on an example system for which the WinIGS data files are provided under the study case name IGS_AGUIDE_CH04 The single line diagram of the example system is illustrated in Figure 4 1 The example system consists of two transmission lines two equivalent circuits two equivalent sources two distribution lines a substation model consisting of delta wye connected transformer and a grounding system Step by step instructions lead the user through opening the case data files viewing the system data run
213. viewing the system data running the analysis and inspecting the results BUS10 g AE BUS70 BUS50 T Customer 2 Figure 3 1 Single Line Diagram of Example System IGS AGUIDE CH03 B3 1 Inspection of System Data The example system consists of two transmission lines two equivalent sources two distribution lines a substation model consisting of delta wye connected transformer and a erounding system You can inspect the parameters of the example system components and make any desired changes by double clicking of the component icons Once the inspections and modifications are completed save the study case and proceed to the analysis section Page 140 WinIGS Training Guide B3 2 Analysis It is recommended that a base case analysis is performed first in order to verify that the system model is consistent Click on the Analysis button and select the Base Case analysis mode from the pull down list default mode and click on the Run button Once the analysis is completed a pop up window appears indicating the completion of the analysis Click on the Close button to close this window and then click on the Reports button to enter into the report viewing mode Select the Graphical I O mode and double click on all system components to view the voltage and current reports The results should consistent with normal system operation Specifically voltages should be nearly balanced Phase voltage magnitudes should be near nomin
214. w Legend Font Size Factor 3 500 Specified Contour Draw a Contour at 300 000 Volts Figure 5 11 Plot Frame Parameters Form for Commercial Installation Grounding System Area DISTR group Next close the all parameter forms and click on the Update button to obtain the touch voltage equipotential plot which is illustrated in Figure 5 12 Note that the maximum touch voltage occurs near the center of the lower right mesh of the substation grounding system The actual maximum touch voltage value is 1241 Volts while the maximum allowable touch voltage is 716 Volts Page 167 1 2 Co 4 C1 Oo N co co En e r ER ine Co cis A Grid Spacing 1000 0 ft Model A JE X Equi Touch Voltage Plot B Vperm 716 V Vmax 1 241 kV u S 243 1V 342 9V 442 7 V 542 5 V Communication Tower 642 2 V 142 0 V 841 8 V s CO tay Cc Equi Touch Voltage Plot perm 716 V Vmax 641 1 V ine A 58 34 V 116 6 V 4 174 9 V 233 2 V N 291 4 V 349 7 V L 408 0 V 466 3 V 524 5V ES lt 582 8 V Substation Com
215. xt close the Sequence Networks form and the Sequence Parameters form by clicking on the Close button of each form and click on the Mutual Zero Sequence Parameters button of the Transmission Line Parameters Selection form see Figure 9 2 This action opens the Mutual Zero Sequence Parameters form which is illustrated in Figure 9 5 This form summarizes the line construction parameters conductor sizes distances line length etc for the two selected circuits and displays the total mutual zero sequence parameters for the selected circuits The Series Zero Sequence Impedance is given in both Ohms and The Shunt Zero Sequence Admittance is given in both milli Mhos and These parameters are computed at the system base frequency 60 Hz in this example The voltage base used for the values is equal to the geometric mean square root of the product of of the rated voltages of the two selected circuits Note that this form is applicable only to mutually coupled transmission line elements containing two or more three phase circuits Since the selected transmission line element comprises exactly two three phase circuits by default the form displays the mutual zero sequence parameters of these two circuits If more than two circuits are present you can view the mutual zero sequence parameters of any desired circuit combination by clicking on the buttons located at the top of the sequence parameter form WinIGS Training Guide Page 197
216. y and paste operations to create the parts for the other two phases Then edit the properties of all phase and neutral conductors to assign proper Group numbers and optionally Layers Finally manually add the overall jacket armor etc Editing Techniques You can select single components by a single left mouse button click or multiple components using a left click and drag mouse action defining a rectangle enclosing the set of components to select Selected elements can be copied and pasted using the copy and paste toolbar buttons or by pressing the F3 function key A left double click on any component opens the property dialog window for the selected component If multiple components have been selected then the property dialog windows of all selected components are sequentially opened If you are using a mouse with a wheel you can zoom using the mouse wheel Alternatively a number of zooming options are provided in the vertical toolbar See Table A1 1 You can shift the view vertically or horizontally by holding down the right mouse button and dragging the mouse pointer about the editor view Attention must be paid not to create multiple overlapping conductors Overlapping conductors result in failure to compute the cable admittance matrix Use of such a cable in any WinIGS analysis function will terminate the analysis with an error message WinIGS Training Guide Page 87 The vertical toolbar button contains buttons that perform the mos

WinIGS Training Guide - Advanced Grounding Concepts

Contents

Download Pdf Manuals

Related Search

Related Contents