Capstone Design Document
Contents
1. Capstone Design Document Texas Integrated Energy Solutions Author Josh Kirksey Email jkoutback tamu edu Phone 281 813 3320 Due Date 10 21 2009 Delivery Date 10 21 2009 Table of Contents Li Problem Statement rie 1 Il Functional Requirements a ciao 1 A I RTT m LIN TET LM 1 B Selectable PE 2 Gi Othe mST 3 III Conceptual Block Diaualfi ea RR EAE Rape Ela da be KR Hes 4 IV Penormance Requirements ieri 5 V Technology Survey Assessment e 6 VI Detailed Functional Block Diagram norint enne enhn nn ni inns 8 VII PPs 9 A Functional Block Diagram uere uno bx rena ii a Dr hl rt PRU i 12 B Functional Requirement Documentation rien rrnrna 12 ETR 12 D Preliminary SCHE MatiCS ssseresrerrresrerrresrerrrrr rer rss rer rss rer rskr KRKA KKR KRK 12 E Software FONT Essen 13 F Preliminary PCB Layout ssissssessessresrersresrerrrssrrrrrrr rer rrrr rer rskr rer KKR KR rasa 13 G Final Schema dti sen bi gr Rt ea 13 H Final PEB ESyVOUL ai 13 l Bill Of Materials t EM 14 J Final Code SECURE 14 Ko Test ONE iii 14 Le ASOSE V ITE TT 15 M User Manual m 15 N Final Documentation acari 15 O Final Prototype arsine aiy OO ARR ERA 15 VI Milestone e allea i ae iii 15 A Sensor PUNCHONBIILY enesis e vela 18 1 Lab environment operation uc otc is eate dox bx arx phe dh CHER RE 18 2 Field environment operation ris sne ers rea 18 CBMO9 Revision2. Cost analysis for the CBMOO can be described as a financial breakdown of labor hours workspace hardware parts software design suites packaging test equipment and printed media Analysis for these items include direct and indirect costs other costs profit and total project costs The costs analysis report will be continually updated throughout the life of the project and will be handed to Oncor as a Microsoft Excel spreadsheet in both hard and soft copy User Manual A user manual of the CBM09 includes a setup guide for Oncor substation technicians to safely and successfully mount the CBM09 into the circuit breaker s control panel The manual also includes information regarding the device s operational characteristics GUI interface and troubleshooting tips Final Documentation The final documentation will be given to Oncor upon completion of the CBM09 The document will contain a compilation and comprehensive summary of all project information The project summary description of CBM09 components an explanation of all tests performed and their respective results submitted deliverables project timelines software code relevant component data sheets PCB schematics PCB layouts cost analysis and user installation guide manual will be included The final documentation will have enough information on the CBMOO to allow recreation of the device This deliverable will be submitted in both hard and soft copy format using Microsoft Word fo
3. 1 19 2010 Functional block diagram 1 19 2010 1 19 2010 ai pedi Functional Requirement Documentation estie 2 1 2010 2 10 2010 Software Flowchart 2 5 2010 Preliminary Schematics 2 12 2010 Preliminary PCB Layout 2 26 2010 Final Schematic 3 1 2010 3 12 2010 Bill of Materials 3 8 2010 Final PCB Layout 3 31 2010 Final Code Listing 4 1 2010 4 12 2010 Test Report 4 22 2010 4 27 2010 Cost Analysis User Manual 5 1 2010 5 10 2010 Final Prototype 5 10 2010 Final Documentation 5 17 2010 Figure 3 Deliverables Timeline CBM09 Revision 1 11 Functional Block Diagram The functional block diagram will contain the technical details provided in a simplified block form The creation of the diagram will be done with Microsoft Visio and will be converted into a PDF format for delivering The details of the functional block diagram will include high level hardware components such as the PIC processor communication chips conditioning blocks and power conversion blocks Internal signals and external inputs will be color coded arrows connecting various components in the CBM009 Inputs to the device are detection sensors user selection dip switches and input power Outputs from the device will be the LED alarm lights and the communication ports sending information back to a control house or a data logging device Functional Requirements Documentation T LE S will be updating and defi
4. 1 ii IX CBMO09 B Power Subsystem Supplies Correct PoWer 18 C Signals are Properly Conditioned reda 18 D Data Processing AIGOrithlM ssmessrressrrersrrrrsrrrrrrer reser rrrr ger bFRa KKR KRKA V EntEs 18 E COMMUNICATION Porri ire ini 19 1 R5 485 has Correct Output 19 2 RS 232 has Correct Output and Accepts Input 19 F FORTGANG 19 G Funetional FIRIMtest ca 19 aaa ioni 20 Gantt Chart Revision 1 Problem Statement In the power transmission world circuit breakers are used to prevent damage to equipment in the power grid Damage caused by fault currents is what circuit breakers try to prevent A fault current is caused by either a short to ground or by two power lines contacting each other which reduces the resistance the system sees Both of these faults cause the current on the line to rise to unsafe levels that can damage other power transmission equipment When a fault occurs a circuit breaker is used to open the circuit on which the fault occurred so that customers and the company s property is not damaged Customers do lose power when the circuit breaker opens the circuit powering their section of the grid When a circuit breaker fails to open the circuit that just experienced the fault condition breaker failure has occurred Breaker failure causes all protection equipment switches and or other circuit breakers directly connected to the breaker
5. in Circuit Breaker RS 485 to SCADA Package Processes trip signals Figure 1 Conceptual Block Diagram The CBMO90 is placed inside the circuit breaker and uses sensors to measure the current across the trip coil of the circuit breaker The current measurements are processed by a microprocessor to determine what type of fault occurred The information about the fault is relayed to the substation control house by RS 485 communication protocol The substation control house then relays information back to the power delivery central control The CBM09 also allows for user interfacing using RS 232 and user input switches The RS 232 port allows a user to interface a laptop with the device to collect a data log of trip signatures The switches allow the user to configure the CBMOO for different types of circuit breakers in a substation This allows the CBM09 to work universally with current as well as older circuit breakers CBM09 Revision 1 4 Performance Requirements The following are the performance requirements of the various parts of the CBMO9 Power Component e Step down 48V 125V DC to 12V DC to supply to voltage regulators e Voltage regulators supply correct power to other components Envelope Detector e Rectify negative voltage from current transformers to positive voltage e Create an envelope around rectified waveform and limit max voltage to 3 3 V to be used by PIC processor Signal Conditioning e Us
6. to open the circuit and cut off the power being supplied to the down breaker This can cause customers to lose power for a longer period of time and it costs the company money When a breaker failure occurs it is important to quickly diagnose the problem with the breaker so that repairs can be made and power can be restored to the customer Currently there is no device or method that can diagnose the problem with the breaker when it fails or let the power transmission company know that breaker failure has occurred Our solution is the CBM09 The CBMOO is designed to fit inside the cabinet of a circuit breaker and it uses sensors attached to it to monitor the key functions of the circuit breaker Based upon the analysis of the data collected by these sensors the CBM09 can determine if a problem has occurred with the operation of the circuit breaker If a problem is detected the CBM09 will raise an alarm which can be sent to the company s central control indicate the problem with an LED on its case and provide detailed information to a technician connecting to it with a laptop Functional Requirements The functional requirements for the CBM09 have been divided into three categories requirements for monitoring requirements for user selectable parameters and other requirements Monitoring Status of the trip coil The device must measure the trip coil s current in order to monitor the circuit breaker s health The device must be check
7. transformer a digital one will be read and if no current is flowing a digital zero will be read by the PIC The a contact sensor and trip coil sensor have yet to be determined There is a possibility of directly connecting to the a contact if a sensor solution does not work For the trip coil a Hall Effect sensor is one possibility The Hall Effect sensor would monitor the current through the trip coil based on the magnetic field detected The readings from the sensor could then be used to determine what type of abnormality occurred in the circuit breaker The user switches are connected to the digital inputs of the PIC processor The user can select a higher or a lower sensitivity 3 or 5 cycle time and capture reference with the switches This will allow the CBMOO to be used with older or newer circuit breakers Based on if the switch is on or off the logic generated will be used by the PIC to determine what settings to use for the CBM09 The outputs from the PIC are digital outputs to the LED alarm lights and the UART outputs to the MAX485 and MAX232 The LED alarm lights are used to show what type of error happened in the circuit breaker This will allow a person to visually see what type of error occurred without the need of connecting to the RS232 interface The MAX232 and MAX485 devices convert the UART data from the PIC into RS232 and RS485 respectively The RS232 port will allow a user to connect to the CBM09 and obtai
8. MO9 Revision 1 16 TEXAS INTEGRATED ENERGY SOLUTIONS 1 19 2010 1 26 2010 Sensors Demo in Lab 2 1 2010 2 2 2010 Sensors Demo in Field 2 9 2010 Power Subsystem Demo 3 1 2010 3 16 2010 Demo Signal Conditioning 3 23 2010 Demo Data Processing Algorithm 4 1 2010 3 29 2010 Demo RS 232 amp RS 485 4 20 2010 Demo CBM09 in Lab 5 1 2010 4 30 2010 Demo CBM09 in Field 5 10 2010 Figure 4 Milestones Timeline CBM09 Revision 1 17 Sensor Functionality The first milestone is sensor functionality Sensor functionality will show the capabilities of the sensors in both lab and field environments Each demonstration is important because the sensors are vital in detecting abnormalities within the circuit breaker Sensor Measurements in Lab Oncor will provide us a circuit breaker for lab testing T LE S will demonstrate that the current transformer sensors will accurately track current flowing through their circuit breaker Other sensor demonstrations include the trip coil sensor tracking current through the trip coil and the a contact sensor telling the status of the a contact This demonstration will be done on January 26 2010 Sensor Measurements in Field Once the sensors have been demonstrated in the lab the following week T LE S will have a demonstration of the sensors out in the field The sensors will be shown to work at the substation with heavy EMI presence This demonstratio
9. e anti aliasing filter to filter out noise from sensor e Condition signal to be usable by PIC processor Communication e Use MAX232 device to convert UART output from PIC to RS 232 e RS 222 port allows for laptop to be interfaced with device e Data from PIC can be transferred over RS 232 to laptop e Use MAX485 to convert UART output from PIC to RS 485 e Data from PIC can be transferred over RS 485 via Distributed Network Protocol DNP PIC e Use algorithms to analyze data obtained from sensors in order to determine what error occurred e Produce correct output to MAX232 and MAX485 devices e Light LED corresponding to problem e Store a data log in flash memory Erasable Electronic Programmable Read Only Memory CBM09 Revision 1 5 Technology Survey Assessment The technology survey assessment is to compare and contrast different components that are important for the operation of the CBM09 These key components include a DC to DC converter PIC microcontroller MAX485 MAX232 and current transformers DC to DC Converter Pros Cons UWR 12 250 D48 e High efficiency e Low operating temperature range e Expensive over 50 NDH4812SC e Cheaper under 20 e Lower efficiency e Meets operating temp requirements NDL4809SC e High efficiency e More expensive over 20 e Meets operating temp requirements The DC to DC converters in the table above are comparing converters that accept 48V inp
10. er information will include the name of the company that owns the software T LE S the date the file was created the last modification date a list of contributing authors and an operational summary of the code For the CBM09 s software components and the user waveform capture program the following format will be used for categorizing the folders project implementation source files header files support documentation and additional includes The project implementation folder will contain the Visual Studio and MPLab files The additional includes folder will contain the libraries of precompiled code used in the project Due to the length and nature of source code the developed source code for the CBM09 and user waveform capture program will be submitted in softcopy format and upon request in hardcopy format The submission will also include a list of software and hardware required for the code to function and will be included in the softcopy submission if possible Test Report The test report will contain the results for every test performed in the test plan including component subsystem and fully functional tests The results will contain any data necessary in order to justify the tests These include measurements graphs tables etc Any errors found in the tests will also be noted in the test report The report will be delivered in soft copy PDF format as well as a hard copy printout CBM09 Revision 1 14 Cost Analysis
11. ield at a substation site All tests will outline what is being tested test limits and how a test is to be preformed The test plan deliverable will be provided as both a hard and soft copy Preliminary Schematics Preliminary schematics are initial drawings of the CBM09 layout Schematics are created for the power component consisting of the DC to DC converter and voltage regulators The signal conditioning component consisting of envelope detector anti aliasing filter and any components necessary to scale the voltage readings from the sensors used by the PIC The PIC CBM09 Revision 1 12 layout including the LED alarm lights and MAX232 and MAX485 devices Schematics will be made using National Instruments Multisim Schematics of each component will be created and a block format will be used to outline the entire system to avoid cluttering Schematics will include part names and labels of all connections This deliverable will be delivered in a printed hard copy and softcopy in a PDF format Software Flowchart A flow chart will be created for both the software for the CBMOO as well as the program used to download the waveforms to the technician s computer The charts will describe the operation of all non library functions within each program by using Microsoft Visio shapes with inserted descriptive text Algorithms used within any of the functions will be mentioned and fully detailed if possible The flow charts will be created i
12. ing for an open or short circuit across the trip coil which would be indicated by the current CBM09 Revision 1 1 2 Trip signature abnormal trip and slow trip The device must monitor the trip signature for abnormal trip which is where the trip signature exceeds the limits of how big or small it can be It must also monitor for a slow trip which is where the time required to trip exceeds the maximum time allowed by the system 3 Re strike The device must monitor for re strike which is where the fault current continues to flow through the breaker after the contacts of the circuit breaker have been separated 4 DC ripple The device must monitor the DC voltage being supplied to the device for an AC component on the signal User Selectable Parameters DC voltage The device allows the user to select between 125V and 48V for the level of voltage being supplied to the device 2 3or5 cycle trip time The device allows the user to select the maximum time allowed for slow trip to occur 3 Sensitivity The device allows the user to select the tolerance which is how close the actual trip signature must be to the reference trip signature 4 Primary current The device allows the user to trigger the end of wave capture which tells the device to stop recording the reference trip signature 5 Record signature CBM09 Revision 1 2 The device allows the user to tell the device to record the reference tr
13. ip signature which captures the initial waveform of the circuit breaker 6 DIP switches The device must provide a switch so that the user can make a selection for each of the parameters above Other 1 Trip signature log The device is able to store several of the waveforms captured during the trip cycle so that someone can compare multiple waveforms to analyze the problem with the breaker 2 PC software for accessing and viewing trip signatures Software is required so that the user can download data captured by the device to a laptop and view it 3 RS 485 and RS 232 communication ports Two communication ports are needed to transmit data from the device The RS 485 port is needed to send alarms to the control house which can relay it back to central control The RS 232 port is needed to allow technicians to connect to the device with a laptop and get operational data on the circuit breaker 4 Size The device should not exceed 10 x 8 x 3 because of space constraints inside the cabinets of circuit breakers 5 Operational temperature range The device needs to able to function properly from 20 C to 85 C due to the operational area of the customer CBM09 Revision 1 3 TEXAS INTEGRATED ENERGY SOLUTIONS Conceptual Block Diagram The conceptual block diagram in Figure 1 displays a pictorial overview of the CBMO09 project and a general overview of how the device operates Sensors Measure Trip Signature
14. ircuit breaker The CBM09 can be powered by either 125V or 48V DC This voltage is then stepped down to 12V and then converted to 3 3V or another voltage to supply power to the other components of the CBM09 A 3 3V voltage regulator supplies power to the PIC The second voltage regulator supplies voltage to the anti aliasing filter and signal conditioning components as well as the MAX485 and MAX232 The MAX485 and MAX232 will be powered with SV At CBMO9 Revision 1 8 this point in the project the components for the signal conditioning have yet to be determined as sensors have not been determined The anti aliasing filter will be an active low pass filter designed with a cutoff frequency of at least half the frequency of the PICs ADC sampling frequency Current transformers CT are used to monitor if current is flowing through the circuit breaker An envelope detector is used to condition the output voltage of the CTs to be usable by the PIC processor The envelope detector consists of a full wave rectifier capacitor and Zener diode The output voltage from a CT can be positive or negative A full wave rectifier is used to rectify the voltage to a positive output capacitor is used to sustain the voltage between peaks of the rectified signal This appears as a pulsed DC signal usable by one of the PIC s digital inputs A Zener diode is used to cap the input voltage going into a PIC digital channel at 3 3V If current is flowing into the
15. l be delivered in the same manner as the preliminary PCB layouts scaled and 1 1 hard copies with Gerber and PDF softcopy files CBM09 Revision 1 13 Bill of Materials A Microsoft Excel spreadsheet will contain a list of ordered hardware components for the CBM09 Spreadsheet details will include manufacturer details a price list quantity number and other necessary information to accurately describe the part ordered The bill of materials gives Oncor insight and the ability to comment about the parts being selected Final Code Listing Source code will be delivered for the CBM09 This includes the user waveform capture program non library classes functions and variables The source code will be documented and titled Creation of a class will start with a block comment that gives the name of the class a short description of its use and the functions it contains Vital class variables may include a single line comment Likewise the created functions will begin with a block comment containing the function name a short description of the function a list of the arguments the argument types and the return value As with classes important variables will be commented Single line comments will also be inserted for important steps within a function C and C source files will include a header file for each source file Both the header and the source files will include a block comment at the beginning with authoring information Head
16. ll be used to convert UART to RS 485 Current Sense Transformers Pros Cons CR8449 1000 Smaller output voltage Measures smaller currents CR8450 1000 Measures larger currents Larger output voltage The two current sense transformer options both have different maximum currents that they can measure The second option can measure a higher value but produces a larger output voltage CBMO9 Revision 1 The output voltage isn t a concern because any output voltage can easily be scalable The second option will likely be implemented because of its ability to measure higher currents Detailed Functional Block Diagram The functional diagram in Figure 2 shows a detailed pictorial view of the CBM09 External Inputs Internal Signals LED Alarm Lights X DC to DC Te VIEN Converter 3 3 Vreg E RS 485 DC 12 V 2 UART Out MAX 485 Data Back to a Control House PIC Vdd EPP Digital Input UART Out MAX 232 Allow For User CT Sensor Detector Interface CT Sensor nede Digital Input RS 232 Detector CT Sensor Envelope Digital Input Detector Digital Input 3 Analog Input a Contact Anti Aliasing Signal Sensor Filter Conditioning Trip Coil Sensor User Switches Sensitivity Cycle Time Capture Reference Figure 2 Functional Diagram The inputs to the CBMOO include the input voltage and the five sensors placed in the c
17. n Microsoft Visio and then will be submitted in vsd format Also a hard copy will be submitted on sectionalized 8 5 x11 sheets of paper Sections will be created based on program flow and visual appeal and continuing sections will use page markers to indicate the preceding proceeding page as well as connections between the sections Preliminary PCB Layout Preliminary PCB layouts are the initial PCB layouts of the preliminary schematic designs This includes the power component signal conditioning and PIC layout PCB layouts will be made using NI Ultiboard The layouts will show all footprints of devices connections between components and component labels Scaled printouts of PCB board layers will be provided on standard 8 5 X 11 paper Additional 1 1 scale copies of the layouts will also be provided Gerber files and PDF versions of the PCB layouts will be delivered in soft copy format Final Schematic The final schematics will be revisions to the preliminary schematics using NI Multisim The final schematics will include any revisions made during testing or design review The final schematics will be used to make the final version of the CBM09 These will be delivered in a printed hard copy and PDF soft copy Final PCB Layout The final PCB layouts will be revisions of the initial PCB layouts The final PCB layouts will include revisions made in the final schematic drawings They will be the PCBs used in the finished CBM09 These wil
18. n a data log of the errors recorded by the device The MAX485 will send data from the CBMO09 back to the substation control house via Distributed Network Protocol DNP Deliverables T LE S will provide items of value called deliverables to our project sponsor Each deliverable represents valued information for team and sponsor assessment The list in Table 1 contains the deliverables and their corresponding dates for the CBMO09 project CBM09 Revision 1 9 Team Deliverable Member Due Date 1 Functional Block Diagram Josh McCracken 1 19 2010 Functional Requirement Josh McCracken 2 Documentation 1 19 2010 3 Test Plan Josh Kirksey 1 27 2010 4 Preliminary Schematics Logan Porter 2 5 2010 5 Software Flowchart Josh McCracken 2 10 2010 6 Preliminary PCB Layout Logan Porter 2 12 2010 7 Final Schematic Logan Porter 2 26 2010 8 Final PCB Layout Logan Porter 3 8 2010 9 Bill of Materials Dylan Kwan 3 12 2010 10 Final Code Listing Josh McCraken 3 31 2010 11 Test Report Josh Kirksey 4 12 2010 12 Cost Analysis Dylan Kwan 4 22 2010 13 User Manual Dylan Kwan 4 27 2010 14 Final Documentation Dylan Kwan 5 10 2010 15 Final Prototype Josh Kirksey 5 10 2010 Table 1 List of Deliverables The deliverables timeline is shown in Figure 3 on the next page and it indicates the time intervals between deliverables CBMO9 Revision 1 10 TEXAS INTEGRATED ENERGY SOLUTIONS
19. n will be done on February 2 2010 Correct Power Supplied The second milestone will validate the board s power subsystem correctly stepping down the input voltage in order to successfully power the hardware components without damaging them Further step downs include 3 3 V for the PIC microcontroller and 5V to the communication chips as well as to different anti aliasing and amplification subsystems This demonstration will be done on February 9 2010 Signals Properly Conditioned The third milestone will confirm the ability of the anti aliasing and amplification subsystem to convert analog signals into acceptable digital inputs for the microcontroller to process Signals from the current transformer are converted into digital inputs that stop at 3 3V Trip coil and a contact sensors will have their noise in the signal removed to represent their true current and voltage readings This demonstration will be shown on March 16 2009 Data Processing Algorithm The data processing algorithm will be the next milestone and it will have a majority of the signal processing algorithms being demonstrated The demonstrations will include its ability to sample waveforms frequently and regularly to detect critical points in the waveform These critical points include first current peak corner point and maximum current peak The data processing algorithm will also graphically show a captured waveform detect if re strike has occurred and CBM09 Re
20. ning the scope of the project to our sponsor Oncor A final document created using Microsoft Word will list and clearly describe the necessary functional requirements of the CBM09 This document communicates all works which will be needed to complete the project No other works or requirements may be added or removed from the final functional requirements document unless agreed on by both parties involved Changes made to the document will require discussion in a conference meeting and an additional change document will be created in which the lead sponsor team project manager and advisor must sign off to alter the functional requirements documentation The document will also be a legal binding source which will be upheld in case of future discrepancies between sponsor and developing team Test Plan The test plan will outline the tests that will be performed on individual components subsystems and the overall device These will ensure that individual components work Then after verifying individual components work subsystems using the components are tested These subsystems include the power and signal conditioning components and communication component The software will have to be tested in order to verify the data processing and communication algorithms are working After the subsystems are tested a lab test will be performed on the device Once the device is tested to work in the lab setting a fully functional test will be performed in the f
21. r document generation Final Prototype The final prototype will be handed alongside the final documentation The prototype will be a fully functional system which meets the criteria provided by the functional requirement document The device provided will include the physical unit in its own enclosure and supporting GUI software for data logging Milestones Milestones will be scheduled demonstrations to our sponsor Oncor Each milestone will be a validation of our device s functionality and will be an indicator of progress T LE S has scheduled a series of milestones with sub categories in a select few demonstrations Demonstrations may be confirmed through our sponsor s participation or through video with approval from the advisor A total of seven milestones will be demonstrated to Oncor T LE S has listed the following milestones in Table 2 for the current project CBM09 Revision 1 15 H Milestone Demonstration Date Sensor Measurements in Lab 1 26 2010 Sensor Measurements in Field 2 2 2010 Power Subsystem Supplies Correct Power 2 9 2010 Signals are Properly Conditioned 3 16 2010 Data Processing Algorithm 3 23 2010 RS 485 has Correct Output 3 29 2010 RS 232 has Correct Output and Accepts Input 3 29 2010 Functional Lab Test 4 20 2010 Functional Field Test 4 30 2010 Table 2 List of Milestones The milestones timeline is shown in Figure 4 on the next page which indicates the time intervals between milestones CB
22. rations and provide a fully functional prototype that is able to work in the lab as well as in the field with EMI All functions of the device must be demonstrated and meet the criteria of the functional requirements document Final demonstration will be shown on April 30 2009 Gantt Chart A Gantt chart is used to illustrate when each phase of the project will be worked on The Gantt chart in Figure 5 on the next page shows our current plan for completing each phase CBM09 Revision 1 19 UTI SJ Task Name Start Finish Duration Dec 2009 Jan 2010 Feb 2010 Mar 2010 Apr 2010 Research 12 15 2009 1 20 2010 27d Design 12 22 2009 3 8 2010 55d Implementation 1 22 2010 3 31 2010 49d Testing 1 26 2010 4 30 2010 69d Procurement 1 22 2010 3 19 2010 41d Wrap Up 4 12 2010 5 10 2010 21d CBMO09 Figure 5 Gantt Chart Revision 1 20
23. ut and convert it down to 12 V output The largest challenge in selecting the converters is to make sure that the output current is not too high The three devices mentioned above all produce a low output current that can be accepted by voltage regulators as well as the MAX232 and MAX485 chips Of the three devices the best solution found was the NDL4809SC It meets the required temperature range and had an efficiency of 83 This was nearly 10 higher than both of the other devices The cost was also in between the cost range of the cheapest and most expensive The DC to DC converter used for stepping down 125 V is the HVA12 CBM09 Revision 1 6 PI C Microprocessor Pros Cons PIC24FJ32GA104 e 2UART channels e No EEPROM memory data memory e Large number of I O pins dsPIC30F4011 e 2UART channels e Less I O pins e EEPROM data memory e Larger program memory e Cost more The PIC24 is the cheaper option It contains 2 UART channels for the RS 232 and RS 485 communication and more I O pins than the dsPIC30 However it contains no EEPROM memory The EEPROM memory is necessary for keeping a data log which can be erased later on The dsPIC30 is more than double the cost of the PIC24 but it has more program memory space with the same features as the PIC24 Due to this the dsPIC30 is a likely processor to be used in the CBM09 The MAX232DW will be used to convert UART to RS 232 The MAX485CS A wi
24. vision 1 18 be able to detect if the DC ripple is too high Lastly the algorithm will tell if non continuity exists across the trip coil This demonstration will be shown on March 23 2009 Communication Ports Communicating information from the CBM09 back to the substation control house will be a critical milestone because information must be relayed in a real time fashion This will help benefit Oncor s technicians in understanding and quickly acting upon the data being delivered to them RS 485 Port has Correct Output The RS 485 port will demonstrate the ability to send data using DNP Distributed Network Protocol and reliably send the data to a control outhouse in the substation This demonstration will be shown on March 29 2009 RS 232 Port has correct Output and Accepts Input The RS 232 port will demonstrate the ability to send data to a peripheral device used for data logging Technicians logging data will also be able to access the microcontroller s memory to download recorded history banks of trip waveforms This demonstration will be shown on March 29 2009 Functional Lab Test The functional field test will include the full system demonstration on the test circuit breaker AII functional requirements must be met in regards to the functional requirements document This test will be the second to last milestone and will be shown on March 20 2009 Functional Field Test This milestone will mark the end of demonst
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