Topic of Thesis
Contents
1. M Total peal a Ee Downstream Utilization Factors V Enable eee Customer loads An A E Cancel Figure 4 18 Load allocation dialog box 2 After completing load data input for targeted feeder click OK then click Run button for load allocation 62 Connected kVA divides the metered demand among the loads in proportion to each one s transformer capacity adjusted for utilization factor Summary of the connected kVA method as seen below Let s and k denote section and phase respectively TKVA k kVA s k x Util Factor 4 5 kVA s k kWallocation s k kWdemand k x aay x Util Factor 4 6 2 kVAR allocation s k kWallocation s k x a 1 4 7 4 17 Power flow calculation 4 17 1 General information Power flow calculation is a basic activity to understand a network situation It produces power flow voltage at each node loss amount etc 4 17 2 Procedure Calculation is selected from Analysis at menu bar Then the following dialog box is apeaed Network Calculation Select Network s Select Analysis 3 M Feeda IV Voltage Drop Analysis I Short Circuit Analysis General Load Model Flag Levels Equipment St Short Circuit IEC ANSI Maximum Number of Iterations 40 iterations Calculation Tolerance for Volts Voltage Clamp Level ld x Report Each Iteration Display a Status Box Balanced Yoltage Drop Include Source2. Q9 Km Q Km A 0 00403 0 726 2 523 0 868 1 0604 186 32 Table 4 5 Ohe conductor characteristics of EDL Continued Medium Voltage Conductor Conductor Diameter No of GMRK GMR Current size mm nor WIR Q Km Q Km A ACSR 240 0 0036 21 77 0 809 7 ET 0 1218 0 1459 ACSR 185 acsriso 00036 1813 30 0826 7488 01830 0 2192 Cacan fome oos e oso ors osso osei ns Acsr35 0 0036 777 6 oso 1 943 0 9090 10890 D a o aao visa akoa Azs CYMDIST software requires being input the following 6 types of parameters for conductor database Conductor diameter Resistance at 20 C Resistance at 75 C GMR Geometric mean radius Nominal rating in summer Nominal rating in winter 4 11 Peak load forecast and load factor The MV load data collection is conductor by utilizing the existing meters at HV MV and MV MV substations The MV load data of each feeder should be recorded or stored at every hour through a year in order to determine the peak load and load factors Figure 4 10 show the photograph of the example of the existing meters for MV feeders at 115kV 22kV substation Figure 4 10 Meters for MV feeders on control panels at 115 kV 22kV substation The required load data on the MV feeders for technical loss estimation are as follow e Active power flow at every hour through a year 53 Power factor at the sending end of substations The lo
3. y a F TATE Y i LA 5 Loss reduction j planning policy B y pf 6 Technical loss reduction simulation A ana Benefit of technical loss reduction Cost of technical loss reduction gt O a Benefit Cost comparison _ Cost saving gt Investment e 5 F a l Yes 7 Summarize technical loss reduction Figure 4 1 Outline of technical loss reduction 42 4 2 Load allocation In general distribution network spreads out widely around the area So it is difficult to grasp the loading situation though out the network accurately In order to calculate the losses in medium voltage MV distribution network power flow of section is required For this purpose load data of each MV LV transformer is need to grasp the power flow Since it is impossible to collect load data of each MV LV transformers CYMDIST software has a function estimate the load of each MV LV transformer instead Once the load of each transformer has been given power flow of each section is determined and loss can be calculated as well 4 3 Process of line drawing Figure 4 2 shows the basic process of line drawing in CYMDIST with actual geographical information Distribution Line Tracking with GPS Tracking the actual distribution lines MV LV GPS record the route information Obtain coordinates information of Distribution Lines Coordinates information along line is collected in GPS Coordinates of equipment specially recorded in GPS Impor
4. An x will appear inside the From node and To node of the section Click the LEFT mouse button and HOLD IT DOWN on the x of the From node or To node Drag and drop the node to a new location or onto another node Show length View gt Show Options Show Conductor length Geographical map creation Select a section Graphical edit command Move disconnect and or connect a section 57 Table 4 8 Basic Software Operation Command Continued A section is internally represented by three sub sections Sections The source end section The Conductor section The Load end section Section properties Section To display section ID View prop gt Show Text gt Section ID Load allocation Analysis gt Load Allocation Control Type possible selecting one of these criteria for connecting and Graphical edit Capacitor disconnecting the capacitor Voltage command Current Reactive Current Power Factor Temperature Time or KVAR CLICK the RIGHT mouse button ONCE on One an O L D symbol Release the button Select an Option from the popup menu Select the circuit symbol to be involved in the action Editing commands Select the icon of the command Network window can be selected into loading data 4 15 Feeder modeling Feeder modeling is a main part of preparation stage for CYMDIST analysis Following information describe the necessary information data for that purpose 4
5. load data of each MV LV transformer is needed to grasp the power flow Since it is impossible to collect load data of each MV LV transformers CYMDIST has a function to estimate the load of each MV LV transformer instead Once the load of each transformer has been given power flow of each section is determined and loss can be calculated as well In CYMDIST Load Allocation function gives the load of each transformer in proportion to the transformer capacity 4 16 2 Data required In order to do load allocation load kW information of each MV feeder is required It must be measured at secondary side of HV MV transformer 61 4 16 3 Procedure of load allocation Load Allocation is selected from Analysis at menu bar Then the following dialog box is appeared Load Allocation Method Tolerance Connected kVA v 0 01 x Demand Type Global demand C Metering point s f Demana Y Options Ignore Motors Ignore Shunt Capacitors F Unlock all Fixed Loads a Save Cancel Figure 4 17 Load allocation dialog box 1 In order for load to be allocated along the feeder in proportion to the transformer connected kVA feeder load data at substation must be set before load allocation Click Demand button for that purpose The following dialog box appears Load Allocation Demand Location Network Id Meterld IFE Demand Type KW PF
6. 15 1 Necessary information data One line diagram Route of distribution line obtained by using GPS at site Location of MV LV transformers capacity Conductor types length etc 4 15 2 Modeling procedure Following describes briefly a feeder modeling procedure Please refer to CYMDIST reference manual for more details e New feeder install Determine a point new feeder starts on study file Then the following dialog box appears Fill in the necessary information including feeder name 58 Properties i Properties Network Source Equivalent Network Source Equivalent Network Source Name Type Equivalent From Eq Database Environment X Name EDL x Color E Voltage KVLL Proximity 000 Traveling time Source Node Node NEW_LINE_81 iy x 118 59860432 Y 158 1682519332255 Network Grouping Area X Voltage level Display F Display in a sub network Cancel Figure 4 12 Network and source properties dialog box When a new feeder is defined and set in CYMDIST study file continue adding sections that makes a feeder e Adding section Along the road in geographical map sections are extended by Add section function with CYMDIST When adding a new section the following dialog box appears Here in this dialog box conductor type shall be selected Length of the section must be decided If there are one circuits in one route conductor type modeled for one circuits
7. 8 M55101 KS510_2 5510 3 A MSSIO4 g a M5511 e M5512 f e wsS1_3 wSS1_4 SS1_5 MS51_6 xj a Feeder Loading Report Substation EDL Total Load Total Load Total Load Cond Losses Xfo Losses Variebie Losses Fixed Losses Network D wa wom ww wom mw ean ww evan ow wan ww wan mw war wm Mest a 07 00 _soea 700 _sooaz7 sozia 1612 003 000 000 ava 03 000 amo WSS1_2 6675 38 66 97 7545 02 97 7545 02 251 94 St 27 617 000 000 GF 17 00 0 MSS1 0 87 0 872 X 3t 0 00 000 31 21 000 oo WE 2000 02 87 0 1740 0 15 ooo 000 54 0 00 MS 87 9 7076 38 76 20 000 000 3 0 00 We 65 00 ory 6 NN 300 000 0 09 jai 33500 30 or 3350 16 0 40 33065016 10705 63 146 56 25291 0 00 oo 146 wal 25291 om v lt gt 3 iteration report teeder Loading Report Connected to 200KVA_VT_captal SLD 25 7 55 Access Database C fle vassanalAnaly 25 7 2555 200kWAR200kVA_YT captal SLD 25 7 S5 mdb SPL_F1_81 in MSSt_1 Phase ABC From SPt_F1_80 To SPL FL_SL Equip Cond ED MV _SACISO Length 371 3 m Figure 4 21 Report Window In the table you can view the loss at each feeder and total loss 4 18 Switching optimization 4 18 1 General information In general there are losses in distribution network However the network configuration change may reduce system loss Switching optimization module in CYMDIST is presented e Selection of switching optimization In order to implement a switching optimization analysis
8. Location At From Node E Unknown Status Connected v State Devices Add X Remove Normal State Normally Closed ages Current State Coe M P Overhead Line Balanced D Normal Infeed Undefined paie hase Switch At From Node TCC Settings Locked closed Meter Operation Navigator Back Figure 4 15 Section properties dialog box 3 60 Following is a dialog box for capacitor bank modeling Section Properties Section SPL_F1_81 id LISERDEFINED nd as gi gE SPL F181 ion At From Node xl ase V A V B Vc 0 00 kVAR phase Rated voltage 0 00 kY L N Type anua Figure 4 16 Section properties dialog box 4 In CYMDIST there is a function that determines an optimal placement of capacitors see later chapter The above dialog box appears when capacitor is modeled manually and asks you to determine the Rated Power kVAR and Rated Voltage kV When capacitor placement with CYMDIST is done capacitor modeling is done automatically When modeling is completed load allocation comes next the power calculation is ready to do 4 16 Load allocation 4 16 1 General information In general distribution network spreads out widely around the country So it is difficult to grasp the loading situation throughout the network accurately In order to calculate the losses in medium voltage MV distribution network power flow of each section is require For this purpose
9. can be selected You will find a type for example EDL_MV_SAC150 for one circuit in one route At bottom right in dialog box equivalent impedance is pre set You do not need to change Section Properties Section Overhead Line Balanced SPL FL 81 Type Overhead Line Balanced gt Phase VA MB vc Number SPLF181 Failures Environment Length 371 259387 m Calculate Unknown X Settings Devices A a K a Lineld EDL_MV_SAC150 zi Nodes Overhead Line Balanced Spot Load Three Phase Equivalent Impedance R jx ohm km B uS km z fo200 fosss2 jsn T zo o3542 fisz ais pa Ss as Ss Navigator Back Cancel Figure 4 13 Section properties dialog box 1 e Adding loads Loads in a feeder are modeled as spot load or distributed load at each section It is assumed that if there is a MV LV transformer in a section there is a block of load spot load or distributed load It is interpreted that modeling a load is the same as modeling a MV LV transformer In case of spot load its location must be determined There are three locations where spot load could be set as follows At From Node At To Node and At 59 Middle In the same dialog box there is a cell that is asking a Connected Load kVA This should be a capacity of transformer At this time you do not need to set Actual Load because it is assigned automatically by Load Allocation described in the next chapter If you have me
10. pea ey Cancel Figure 4 23 Switching optimization 2 In the above dialog box there are some objectives for optimization calculation For the loss reduction purpose minimize kW losses is the objective In minimizing kW loss there are two types of calculation algorithm Global branch exchange and Local Branch Exchange Local branch exchange considers the load transfer by modifying the configuration of tie points individually On the other hand global branch exchange considers tie point operations simultaneously in order to find a more efficient way to feed local customers With this method the option of adding new switches can be activated After choosing an objective click Run button to calculate It is recommended that new interconnections between feeders are set modeled as many as possible so that CYMDIST can explore as many candidate configuration as possible to find an optimal solution It should be noted that if a 65 switch of new interconnection is presented t close loss reduction planning should include its construction It is recommended that switching optimization operation by CYMDIST be continued until it does not improve its situation e Results When CYMDIST completes the calculation for switching optimization it presents a switching optimization report including Switching operations Network summary System losses Switching operations show the new status of switch open or close
11. per C HD copper a 0 00381 per C ti amp to base and new temperatures respectively Example The resistance of Wolf at 20 C is 0 183 Q km R75 c R29 c 1 0 00403 75 20 0 183 1 22165 0 2236 Q km 4 8 3 GMR Geometric Mean Radius Geometric Mean Radius GMR is a parameter to evaluate the internal inductance which depends on physical and magnetic properties of the conductor In general the overhead line uses the stranding wire that consists of several wires and or cores Figure 4 7 illustrates the GMR The conductor of radius r with uniform distribution of current density is equivalent to the pipe shape conductor with the current on the circumference of GMR The current flows on each stranding of 48 overhead line almost equally therefore the internal inductance can be evaluated by GMR It is usually provided by conductor manufacture Figure 4 7 Geometric mean radius GMR All Aluminum conductor AAC uses the same stranding configurations in different sizes Therefore the GMR of AAC is defined by the following formula uniquely On the other hand ACSR uses different materials in its core to reinforce the line so that the following formula is not applicable to ACSR N2 GMR EN DN D 4 2 Where N Number of stranding Dmmie 4 x radius if stranding 0 7788 r for a cylindrical strand The following expressions give more practical and easier option to evaluate GMR by given coefficient GMRx GMR ra
12. v MSS6_5 Desired M559_3 Loading Power Factor Time at loading 4 4 of year Light load 40 98 30 Normal load 60 38 40 Peak load s0 38 30 Notes The time at loading determines which load level will be optimized first To ignore a load level set the values to zero Run Save Close Cancel Figure 4 26 Optimal capacitor placement dialog box 2 e Results After the capacitor placement analysis the result box tab is displayed automatically Under the optimal location s capacity of capacitor location s etc required for its objective are displayed in the information box for each feeder targeted for capacitor placement analysis Results are displayed for each of loading level such as light normal and heavy load Figure 4 27 1s the image of Results tab 68 Optimal Capacitor Placement Set feeders Restrictions Capacitor Banks Load Levels Cost Options Resuts Optimal location s MSS6 5 MSS9_3 i Light load 40 0 wis ain F9 3_274 Apply Capacitor F9 3_633 Normal load 60 0 F9 3_274 Options F9 3_633 Information Peak load 80 0 Wr F3 3_274 Fixed 600 kVAR total F9 3_ 633 Switched 300 KVAR total ie Loss reduction 29 4 kw total F9 3_469 Voltage dv 4 30 Figure 4 27 Results tab for optimal capacitor placement The information box below right indicates the optimal solution of each section Solution is in
13. 0 4 9 Pole configuration Spacing The conductor property and pole configuration are required to calculate the line impedance Pole configuration is related to the Geometric Mean Distances GMD which is used to determine the self and mutual impedance of the line The GMDs between phases and between phases and neutral are defined as follows Phase to Phase D GMDj Dap X Dpe X Dac m 4 3 Phase to Neutral Din GMDin Dan X Dyn X Den m 4 4 Where Da is the distance between phase a and phase b Dj 1s the distance between phase b and phase c Dac 1s the distance between phase a and phase c The pole configuration determines the vertical and horizontal positions of the conductor CYMDIST can calculate the GMDs if the vertical and horizontal positions of conductor are given Table 4 4 Positions of standard pole configuration for MV system SWER Horizontal m Vertical m Horizontal m Vertical m Horizontal m Vertical m 00 10 I 0 W OO OT 0 J 0NF A h 2A O75 10 HF A Al A ia 3 239 10 23 Aggy io Z NY Anewtra AW A 7IN S N FJ ON 1 388 930 GMD ANA e A A S A Eny y 1 55m 0 75m Figure 4 9 Aspect of standard pole configuration of MV and LV system EdL applies three phase three wire system and three phase four wire system for MV and LV network respectively There is no neutral conductor in MV system Figure 4 8 Table 4 4 shows the positions of each phas
14. 953 35 5 300 09 6 148 10 MSS 6 6 7 009 27 7 499 91 8 699 90 MSS 6 7 8 793 99 9 409 57 10 915 10 MSS 6 8 7 102 72 7 599 91 8 815 90 MSS 1 1 4 579 36 4 899 91 5 683 90 MSS 1 2 6 074 77 6 500 00 7 540 00 MSS 1 3 3 925 23 4 200 00 4 872 00 Sokphalaung MSS 1 4 1 426 84 1526 72 1 771 00 MSS 1 5 5 700 93 6 100 00 7 076 00 MSS 1 6 5 420 48 5 799 91 6 727 90 MSS2 1 7 009 18 7 499 83 8 699 80 MSS2 2 6 040 04 6 462 84 7 496 90 MSS2 3 3 644 86 3 900 00 4 524 00 Sisakhet MSS2 4 1 308 41 1 400 00 1 624 00 MSS2 5 3 364 41 3 599 91 4 175 90 MSS2 6 7 476 64 8 000 00 9 280 00 MSS3 1 5 684 90 6 082 84 7 056 10 MSS3 2 4 859 73 5 199 91 6 031 90 Thatlaung MSS3 3 4 766 27 5 099 91 5 915 90 MSS3 4 4 618 92 4 942 24 5 733 00 MSS4 1 9 345 71 9 999 91 11 599 90 MSS4 2 16 542 70 17 700 69 20 532 80 Dongnasok MSS4 3 8 438 61 9 029 31 10 474 00 MSS4 4 1 869 16 2 000 00 2 320 00 55 4 12 Cost of technical losses The cost of countermeasures against technical losses is as shown in the following table consulting with EDL counterparts In the feasibility study phases the precise cost estimation would be required Table 4 7 Cost of countermeasures against technical losses Items Maintenance cost for fixed capacitor 0 06 USD kV AR year Maintenance cost for Switched capacitor Switched capacitors Installation disconnect switching DS of MV lines 4 13 Statement of studies system ed Ns A ADANI A X t a Ff 1 Pa W
15. CHAPTER 4 Power Systems Analysis The power distribution loss ratio of EDL including both technical and non technical losses was recorded 11 83 in 2010 In Electricit du Laos EDL there are divide 3 regions such as Northern Central and Southern Electricity regions Table 4 1 Distribution loss of EDL s branches in 2010 Sent out from Received from Distribution Distribution No Name Branches Substation Bills Losses Loss kWh kWh kWh Ratio Northern Northeen Region _ eee 7 Ne eee eee 1 Phongsaly 838 214 754467 83 747 wart a 8 590 183 8080872 509 311 6 Xiengkhouang 14 962 018 13571064 1 390 954 9 30 8 Xayaboury 28 015 152 24425620 3 589 532 12 81 9 Vientiane Province 227 973 963 217080260 10 893 703 4 78 Toan 357 788 083 333 548 328 24 239 755 6 77 en A SO Ae AN le ee a fs T Soutnern Region O 17 Xekong 5891190 5301829 583361 990 O Toa 355453988 310 184 747 44969241 12 66 Total ali regions 1 257 810 958 1 109 003 403 148 807 555 11 83 4 1 Approach to power distribution technical losses Technical losses in power transmission and distribution systems are caused mainly by the resistance of conductors the magnetic consuming energy following a hysteresis loop of an iron core of transformer or eddy current flows The other miscellaneous losses such as corona losses and leak current through insulators are relatively small Distribution technical loss
16. IST program analysis CYMDIST is software developed by CYME international that works on a PC used for power distribution system analysis and can perform several types of analysis on balanced or unbalanced three phase two phase and single phase systems that are operated in radial looped or meshed configurations The modules that EDL has obtained and utilized for loss reduction analysis includes per phase voltage drop and power flow analysis optimal capacitor placement and sizing load balancing load allocation or estimation and switching tie points optimization Data required Load data feeder wise Geographical information Data Collection i System Network data Modeling Network Modeling Power Flow Output Calculation Power Flow Results Feeder Loss Network Loss Jna yers Lb Viltage Profile Analysis amp Planning Measures Planning Reconductoring Switching Optimization Capacitor Placement New feeder New Substation Figure 4 3 Outline of distribution technical loss reduction planning procedure Technical loss reduction simulation is run with making combinations of the following functions Load balancing calculation Switching optimization Capacitor installation 44 The following functions of the software are used e Load allocation This function can allocate the load in the feeders based on the load data at the sending point of the feeders and the information of the facilitie
17. Impedances Regulator Operation Starting Motors Normal Tap Operation Set as Running Infinite Taps C Set as Disconnected M Adjust to Lowest Tap SESS K K S S o K K SS Save Cancel Figure 4 19 Network calculation dialog box In the above box Voltage Drop Analysis is selected to calculate the power flow Before Run calculation conditions are checked The click Run to get calculation results In order to view the calculation results including loss of each feeder choose On Calculation from Report at menu bar The the following dialog box is appeared 63 Show Networks X Voltage Drop v E v Properties v Abnormal conditions Properties s Complete Properties D Feeder loading Properties v A ottage drop Overloaded conductors Properties C voltage drop Summary Properties Figure 4 20 Reports dialog box Check the Voltage drop Feeder loading to view Then Press OK The following table appears Cymdist 4 7 17 default xst Window 1 Ti File Edt Equipment Analysts Report Wew Tools Customize Window Help DOS E SAP OF A 4dr PPP tE Y T zE eX A fov capa s2575 e O Conductor aze colo amps t E Dets Tags E Voltage Drop g A Wia DEFAULT Load Hodel v amp A Voaz Dop ee ee ee E a eS ee EL Ri Rigs Cin OR iD kd k Arto x Feeda H7
18. ST software 4 5 and 4 7 versions as seen Appendix E
19. Switching operation results 4 19 Capacitor placement for distribution network 4 19 1 General information Capacitor 1s capable of compensating reactive current that is required by system load By installing the capacitor current flow in the distribution system is reduced thus the system loss reduced as well Capacitor also has voltage maintaining characteristic It can reduce voltage drop during heavy load period When capacitors are connected to the distribution feeder they inject the reactive power current that reduces the current flow During the light load period capacitors may cause voltage 66 rise that exceed the permissible voltage range It should be cautioned Capacitor is not so expensive that it is easily applied 4 19 2 Data required for CYMDIST analysis The following data is required for the capacitor placement e Capacitor bank unit size e Loading conditions 3 step loading levels Light Normal Heavy CYMDIST is capable of calculating the appropriate amount of capacitor according to the loading level The loading level is determined by the percentage level to the peak load Based on the fixed amount of capacitor required for the light load period it can calculate the amount of capacitor for normal load and heavy load period as on off switchable capacitor In addition to the loading level setting it must be determined how long each of 3 step loading level continues in a year Desired power factor is also required T
20. able 4 9 Loading conditions Loading conditions Loading Desired Power Time at Loading Factor 2 al gt WY Y VIl Pf Yea Ol A 90M Z WO Light Load Normal Load 60 9 4 Peak Load DI VAKS S gt JS BQ Sf e Process of capacitor placement by CYMDIST Feeder loading on CYMDIST and select an objective function such as factor correction loss reduction voltage rise etc Capacitor bank selection so that CYMDIST can choose the bank applied in the system Setting of loading conditions so that CYMDIST can indicate how much the fixed capacitor or switched capacitor required e Run the CYMDIST Figure 4 25 is presented from Analysis in the menu bar and then select Capacitor Placement You need to choose the objective function Load level information should be filled in Figure 4 26 It is presented in the Load Levels tab 67 Optimal Capacitor Placement Select feeders Feeders Ubjetye v MSS6_5 mrnize kW losses Improve system voltage v MSsS3 3 Restrictions Minimum loss reduction Maximum voltage rise I Power factor limit Min distance from substation Min distance between banks Maximum fault current ee V Ignore single phase l Ignore these location s IV Ignore two phase Ignore three phase V Ignore underground irs Run Save Close Cancel Optimal Capacitor Placement Select feeders Feeders n Loading conditions
21. ad data at every 8760 hours during 2011 were collected for the 47 feeders in Vientiane capital The peak load of each feeder was determined on the load duration curve drawn by plotting a sending order of load except for no load duration during a year The load factor of the feeders were calculated by the ratio of the peak load identified in the abovementioned manner to the actual sending energy of a feeder The unified load factor was calculated by averaging out the load factors of the feeders The load factor was 0 5 on the weighted average of MV feeders of Vientiane Capital The peak loads at both of 2013 and 2015 is determined based on the demand increase rate used in power development plan PDP by EDL The peak load of MV feeders used for technical loss analysis were estimated as shown in Table 4 6 Power factor was assumed 0 8 at a delivering point at a substation The capacities load of transformers estimated load from chapter 5 Table 4 6 Peak loads of MV feeders used for technical loss analysis 54 Table 4 6 Peak loads of MV feeders used for technical loss analysis Continued MSS 9 1 5 427 81 5 807 76 6 737 00 MSS 9 2 4 504 43 4 819 74 5 590 90 MSS 9 3 12 082 26 12 928 02 14 996 50 Koksa at MSS 9 4 7 476 62 7 999 98 9 279 98 MSS 9 5 3 197 71 3 421 55 3 969 00 MSS 9 6 4 953 29 5 300 00 6 148 00 MSS 6 1 6 355 06 6 799 91 7 887 90 MSS 6 2 654 21 700 00 812 00 MSS 6 4 5 981 34 6 400 03 7424 03 Thanaleng MSS 6 5 4
22. asured load data for a MV LV transformer you can use that data as actual load Following is a dialog box for load transformer data Section Properties Section Spot Load SPL_F1_81 Number SPL_F1_81 Failures Phase VA MB vc _Faiwes cation At To Node Environment Unknown Settings Load Summary Load Model DEFAULT Customer Type Commercial Ei Node Normal Priority NONE T 2 Uverhead Line Balanced Uy Sets Spot Load Three Phase Emergency Priority NONE z Locked Year 2011 Devices Disconnected Format kKVA amp PFo v 4ctual Load 73 20 sumption 10 00 T tion Connected Capacity 1100 00 kVA al hc akarna Q z of 4 Navigator Back Next Cancel Table 4 14 Section properties dialog box 2 e Adding equipment In distribution system there are many types of equipment that improves reliability power quality etc For example line switches help the distribution network improve load transfer capability capacitor banks improve voltage profile etc Those kinds of equipment can be model at each section Following is a dialog box for modeling a line switch If interconnection between feeders is needed line switch Normally open is also modeled Location of each line switch is also determined same as spot load location in a section Section Properties Section Switch t From Node SPLISI id Failures Phases WA WB MC Number SPL_F1_81 Environment
23. choose a Switching Optimization from the pull down menu in Analysis Tab For this purpose the network that should be optimized needs to be loaded 64 Cymdist 4 7 17 default xst Window 1 di File Edit Equipment MUEVAS Report View Tools Customize Window Help Dewaa at e pp tB sS el y O JBea gt ry Calculation Parameters Conductor size color amps LoadiAlocatien bas v Voltage Drop v sd A i DEFAULT Load M HS at Load Balancing Sra eo Y m PD tE he Heo w be IRS 2 kesi jg Ee Ciy P Load Growth Capacitor Placement Fault Flow Motor Start Analysis a Feeder 47 m MSS10_1 Harmonic Analysis m MSS10_2 m MSS103 Protective Device Coordination Data Aat m MSS1_5 m MSS1_6 Arc Flash Hazards e m MSS2_1 Network Equivalent Calculation m MSS2 2 m MSS2 3 Network Forecaster m M5524 Network Reduction Detai TY Net gr Sym T Display Figure 4 22 Switching optimization 1 e Execution When you start Switching Optimization function the following dialog will appear Switching Optimization Module Select feeders Parameters Objectives Restrictions Minimize Overload Exceptions Minimize Voltage Exceptions C Balance Feeders by Load C Balance Feeders by Length C Minimi Minimize kw Losses global branch exchange Save Am 7 Ties fai ol pis mias
24. dicating upon selected in the optimal location s box left side In the above image the F9 3 274 is selected and indicating the following 600kVar capacitor is required as fixed and 300kVar as switched The effect of loss reduction by this capacitor installment is 29 4kW If the user satisfies the solution the capacitor is accepted by clicking the Apply Capacitor button The network is updated only in the study file 4 19 3 Loading level setting As mentioned in the previous section the capacitor placement presents a desired amount of capacitor in response to the loading conditions light load normal load and heavy load Therefore the actual annual load curve is needed to convert to the equivalent 3 step loading level Following is the example of loading level setting e Grasp the actual annual load curve Prepare 8760 hour load data for each feeder for particular period Sum up the load of target feeders on each hour of 8760 Total load of each hour is sorted in descending order Draw a curve based on a data prepared in descending order I Peak Load used for Loss Calculation load Load Factor r co of a feeder 8760 Upper 1 in descending order except for 0 MW duration Figure 4 28 Load duration curve 69 Heavy load light load Sample e Heavy load is set upper 10 of 8760 loads Light load lower 10 in the load duration curve e Average of load curve s normal load e Present a percentage loading lev
25. dius of conductor R GMR where GMR coefficient of GMR Table 4 3 Coefficient GMRx 3 O OOB lt 0 49 Example 1 SC AC 3 2 75mm No of stranding 3 diameter of stranding 2 75mm circumcircle stranding Figure 4 8 Configuration of SC AC 3 2 75mm conductor GMR D4 X Dp x Di X D21 X Dz X Dz Xx D31 X D32 X D33 32 I 0 7788 x r x 2r x 2r r X 4 0 7788 x 2 x 2 3 1 4605 Xr 1 4605 X 2 75 2 2 0082 mm R r 2r vV3 2 1547 X r 2 1547 X 1 375 2 963 mm The coefficient GMRx 1s then GMR 1 4605 2 1547 0 678 Example 2 ACSR 150mm2 Wolf the raius is 9 065 mm and the stranding is 30 GMRwoir Radiusyoir x GMRacser stranding30 9 065 0 826 7 4877 mm 4 8 4 Nominal rating Nominal ratings affect the expression of abnormal conditions for overloading in CYMDIST Nominal ratings in summer and winter are given in DDM It classifies the nominal ratings into four types day still air day 0 5m sec wind night still air night 0 5m sec wind Wind has a great effect on the nominal rating This study considers the day 0 5m sec wind under current ratings at 75 C and 45 C ambient in both of the summer and winter because still air condition is uncommon and temperature of Laos is constantly high through a year DDM also points out that even small wind movement greatly increases the current ratings The condition would be appropriate for nominal ratings 5
26. e inputted into CYMDIST which are measured from arbitrary reference point Electrical Power Technical Standard 2002 defines the embedment lengths of several types of poles The 15 m 5I or less reinforced concrete Type A pole needs to bury 1 6 or more of total length DDM also defines the same embedment length as STEP in Part B The common pole length of MV and LV system is 12 m and 8 m respectively The burial depths are 2 m and 1 5 m so the pole lengths over the ground are 10 m and 6 5 m 4 10 Types of conductor Several types of conductors are used in MV system of EDL the generally used conductor s base on British standard and Thai yazaki standard The recent major distribution projects generally used conductors based on British Standards The different types of conductor have also been used in earlier projects such as German standard Table 4 5 shows the conductor characteristics that are categorized as ACSR 150 mm EDL often describes the conductors with only cross section size in single line diagram Therefore it is impossible to specify the type of conductor The electrical characteristics are quite different by each conductor By the same token EDL has categorized many types of conductors into only a cross section size such as ACSR 70 mm and ACSR 35 mm Table 4 5 The conductor characteristics of EDL Medium Voltage Conductor Conductor Diameter No of GMRK GMR Current size mm stranding mm mm
27. el against peak load for each of loading level heavy load normal load light load e In order to draw the step wise yearly load duration curve which is equivalent to the actual load duration curve think about how long each of loading level heavy normal and light continues in a year e The time at each loading level are decided by trial basis example start form heavy 30 normal 40 and light 30 e Considering loss is proportional to the square of load current compare the following two calculations and if both values are almost the same assume that the step wise load duration curve produced by trial is equivalent to the actual load duration curve gt Sum of the square of each 8760 hour actual load gt Sum of the square of step wise load data each 8760 point that includes heavy normal light load e Time in a year finally obtained in the above process is used for the capacitor placement analysis 30 40 30 10 Heavy load MW Loading level 80 1 onl e Normal load MW Loading level 60 i Pee ao ae aw Light load MW i Loading level 40 1 439 S77 1315 1753 2191 2629 3067 3505 3943 4381 46819 5257 5695 6133 6571 7009 7447 FEBS 4323 Figure 4 29 Sample of load level setting time yearly at each loading level 4 20 Copyright of CYMDIST software EDL bought CYMDIST software with CYME international T amp D Inc two phase Phase I bought CYMDIST software 4 0 and 4 1 versions and phase II bought CYMDI
28. es reduction usually focuses on the reduction in conductor losses sharing a large part of transmission and distribution losses 40 The electric current goes through the conductors of distribution feeders with the technical losses in proportion to the square of current expressed by the following the well known formulaP I R Where R is the resistance of conductor and T is the current on conductor for three phase system the losses of feeder becomes 31 R The formula about the conductor losses make clear that power distribution loss reduction can be achieved by the decrease in a conductor resistance or in a current The decrease in conductor resistance can be achieved through system reinforcement such as re conductor or adding new lines The decrease in current can be achieved by the installation of capacitors through power factor correction and Leveling of distribution load or switching optimization The load balancing technique is the interesting loss reduction technique for 3 phase 4 wire system In general the effect of load balancing is more obvious during the peak load period Although this concept is simple and easy to perform utility will not benefit much from this technique Following are the measures widely taken for the reduction in distribution technical losses Correction of unbalanced phase currents or the load balancing Power factor correction by fixed capacitors or capacitor placement Leveling of di
29. ey y iS VF w i s Location of 115kV 22 kV Y Substations 9 Location of 22kV 22 kV Substations Figure 4 11 Overview of the single line diagram of distribution system in Lao PDR 56 4 14 Basic software operation of CYMDIST Software Operations are described in the CYMDIST Reference Manual and User Manual accompanied by the Software licenses Here basic software operation commands abstracted Table 4 8 Basic Software Operation Command File gt Database gt Create gt Single database Database creation gt Microsoft Access gt Database File Create mdb Database Equipment data Input into Created e g Equipment gt Conductor gt New Database Setting up created File gt Database gt Select database File gt New Study Start the new Select the network sheet Start the new study y I study Select the feeder in the network sheet and based on the selected l push the right hand side button on the database i mouth and loading Maps created with GIS software e g Window gt Attach map gt Select Arc view are stored file gt Map selection gt Import gt Add Convert into gfs gt Select File of Arc view gt gfs files Move the Mouse to position the cursor at Zoom one corner of the desired area Double click RIGHT Button Click the LEFT mouse button ONCE anywhere on the section Equipment symbol or tag Or Click the LEFT ONCE and HOLD IT DOWN Select a section
30. ions of the routes of the lines with GPS measurement the electrical data on feeders such as conductor sizes or lengths of the sections The portion of the data regarding the conductors and transformers are use for calculating the net work parameters such as resistance reactance or admittance Those data and information are arranged on the system data to developed and analyzed using CYMDIST program The technical loss reduction are study cases set out so as to be expected effective loss reduction according to the loss reduction policy such as application of larger size conductors or installation of pole transformers Voltage and power flow are checked and loss reduction is calculated as the difference the cases The economical evaluation phase consists of the evaluation of the cost of technical losses and the cost of investment The benefit of technical loss reduction and the cost of countermeasures are calculated from the results of the amount of reduction in technical loss and the additional facilities for technical loss reduction The concepts are of study as seen in figure 4 1 below 1 Load data collection Medium voltage feeder load at 115kV 22kV substations 3 Distribution facility data collection Conductors Transformers Single line Ataarame 2 Load analysis Estimating peak load P Estimatine load factor and loss factor Network parameter calculation mA A z a 4 Modeling the data into the software
31. n line and display the lines with geographical map In case the lines are drawn by AutoCAD software each component of distribution line does not have any electrical data such as line constant Users must input the data necessary for distribution system analysis The following are the major data required for software analysis that must be input when CYMDIST software read the distribution line 47 e Types of conductor detailed information such as line constant is predefined Number of phases e Location of distribution are transformer switching equipment capacitors etc for appropriate distribution system modeling 4 8 Conductor characteristics The conductor database of CYMDIST requires the following four types of parameters to evaluate the overhead line characteristics e Conductor diameter e Resistance at 20 C and 75 C e GMR Geometric Mean Radius e Nominal rating in summer and winter 4 8 1 Conductor diameter The reference manual of conductor manufacturer gives the conductor diameter 4 8 2 Resistance at 20 C and 75 C Conductor diameter and resistance are found in a reference book of conductor manufacturer However the reference book shows the standard DC resistance at 20 C The following expression can convert the standard DC resistance at 20 C to the resistance at arbitrary temperature Ro Rj 1 a t t 4 1 Where coefficient of thermal expansion aluminum a 0 00403 per C aluminum clad steel a 0 0036
32. red for allocating the load at the sending end of the feeders to the feeders with load allocation function of CYMDIST program e Geometrical data The X Y coordinates data of the locations of the marks such as poles of feeders are measured with GPS The X Y coordinate s data are imported to Arc view or Auto CAD as an original map data shown on CYMDIST program Geometrical data of the feeders are made by drawing the location of feeders on the original map in CYMDIST program to obtain the geographical location and the length of the feeders 45 4 6 Load data for distribution technical loss analysis Peak loss and peak loss reduction are calculated from the snapshot of the system models with peak loads The peak load of the distribution system is modeled in software as follows 1 Input the active peak power loads and power factors at the sending end of the feeders in substation 2 The loads are allocated along the feeders in accordance with the connected capacity kW or connected kVA or kWH 4 7 Process of line drawing Figure 4 4 show the basic process of line drawing in software with actual geographical information Distribution line tracking with GPS Obtain coordinates information of distribution lines Import coordinates from GPS to PC in dxf format commonly readable by AutoCAD software Import coordinates to AutoCAD or Arc view software with Lao map and Draw lines feeders along the coordinates on AutoCAD or Arc vie
33. s such as the capacities of transformers or the lengths of the section e Load balancing calculation The balancing analysis will determine which loads can be reconnected to different phases so as to minimize kW losses or balance the current or the load It reports a series of individual changes to the network and kW loss reduction with each change e Switching optimization This function can determine the optimal open points of the network that can be supplied two electric sources such as substation e Capacitor placement This function can determine the optimal locations and capacities of capacitors installed on the network Outline of required data and functions for modeling for using the software is shown in Table 4 2 Table 4 2 Outline of modeling for using the software Data of feeder Geometrical data Load balancing Electric data Power flow calculation Peak loss Voltage Peak load data Switching optimization Optimized open point Capacitor placement Optimized capacitor placement and capacity Peak load data Preparing the data about load as explained in 4 4 peak load and its power factor are required For capacitor optimization light and middle load data are also required e Electrical data The data about conductors with the tables showing the conductor sizes and electric parameters are prepared The capacities of transformers on the feeders are inputted at all the sections The capacities of the transformers are requi
34. stribution load or switching optimization The correction of unbalanced phase currents or the load balancing should be taken through the daily maintenance works of the distribution division of branch offices by changing the phase connected to the low voltage LV feeders Other countermeasures always require the investment in the facilities for countermeasure against losses Leveling of distribution load or switching optimization often requires the interconnections newly installed or the reinforcement of the sections As the investment for loss reduction is made in facilities more the loss would be reduced more However seeking too high loss reduction sometimes requires the huge cost making the countermeasures unfeasible Figure 4 1 shows a flow examining technical loss reduction Load data collection is made about the loads of feeders and the distribution system facilities The load data includes power factor voltage power and etc Those are usually obtained on MV feeders at 115 kV 22 kV substations and LV feeders 22 kV 0 4 kV transformers The 22 kV 0 4 kV transformers are not permanently equipped with any measurement tools a LV feeder load has to be grasped by handy clipping on meters 4 Collected data of the loads are analyzed to provide the peak load and the load factor The estimated peak loads are inputted into the software data The data of the distribution system facilities are collected regarding the geographical locat
35. t coordinates from GPS to PC in dxf format commonly readable by CAD software incLC YMDIST Easy way to draw lines with CAD software when only coordinate information is available Import Coordinates to CYMDIST Import Coordinates to CAD software with LAO map software with LAO map Draw lines feeders along the Draw lines feeders along the coordinates on CYMDIST directly coordinates on CAD Software Draw lines along coordinates Draw lines along coordinates based on the LAO map based on the LAO map Start Analysis on CYMDIST ais aw a onan Figure 4 2 Process of line drawing 4 4 Process of CYMDIST program analysis The MV technical loss reduction is analyzed with CYMDIST program following the process described below in due order 1 Model feeders into CYMDIST program and carry out load allocation to the sections of the feeders 2 Carry out power flow loss and voltage analysis 43 3 Simulate the case with countermeasures to find out the loss reduction kW Conceivable countermeasures are listed in due order as follows Consider utilizing the planned 115 kV 22kV substations and main feeders as much as possible Carry out switching optimization Select the countermeasures for technical loss reduction with confirming conductor sizes and flowing current at sections of feeders Carry out capacitor placement simulation to determine the optimal capacities and the locations of capacitors 4 5 Basic process of CYMD
36. that have changed its status by switching optimization The table of switching operations result indicates the new network configuration So this result should be saved The network summary shows the kW loss of each feeder before and after the switching optimization operation So effects of switching optimization can be checked by feeder wise System loss table shows the summary of loss reduction for entire system indicating the saving amount by switching optimization operation Cymdist 4 7 17 SOM Report Window 1 ae File Edit Equipment Analysis Report View Tools Customize Window Help Cats GRR SF A dink O PPP EBA S EF Bex Conductor size color amps ag Switching optimization Si Switching Optimization 4 A i DEFAULT I ve i ot Bat e Nv x e e e me BD He es eae S e lo l Fo Role Q x a H Feeder 47 gt C S A amp s gt E ai Capacity Initial Load Final Load Initial Losses Initial Length Final Length Feeder id ia oa fa a w w e MSS6_5 20849 6 6978 1 7356 8 158 45 195 53 86292 2 105197 6 174938 9 ea a w a yea maos 1o32 sa oj Iteration report h Feeder Loading Report SoM Report Connected to Switching_VT_capital_SLD_21_5_55 Access Database C file vassana data_25_5_55 edit Reconductor_swiching_interconnect Switching_ T_capital_SLD_21_5_55 mdb Node F9 3_633 X 294315 404210 Y 2012076 493755 Figure 4 24
37. w software Export lines drawn by AutoCAD or Arc view to CYMDIST software Import coordinates to CYMDIST software with Lao map and Draw lines feeders along the coordinates on CYMDIST software Start analysis on CYMDIST software Figure 4 4 Process of line drawing 4 7 1 Line tracking and data transfer In order to track the distribution line GPS equipment which can collect coordinates information is needed When tracking the distribution lines someone must go through along the actual lines with GPS equipment GPS can record the route passed and the coordinate s information is saved in it This is the procedure to decide the line location on the geographical information It is recommended that the coordinates of each distribution transformer switching equipment etc be recorded so that distribution equipment is modeled at an appropriate location Figure 4 5 Line tracking and GPS measurement After tracking the target distribution line the coordinate s data of the line need to be transferred to PC equipped with CYMDIST AutoCAD or Arc view software Figure 4 6 Image of data transfer 4 7 2 Line drawing After the coordinates is transferred to PC imports the data and open the data on geographical map of Lao There are many points of coordinates and the distribution line is drawn by connecting the coordinates 4 7 3 Export to CYMDIST software CYMDIST software can import the AutoCAD or Arc view data with distributio
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