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Honours Thesis Project Report PV Array Troubleshooting and

1. Srl Be 3 2 84 lt 8 2 8 o B o s ol o 8 a F a 2 82 a a 3 2 BPD Switch Bank Qiu Qi Qu Qu vee ES 22 23 23 24 Telergon 8 Pole 2 2 ZE ae ES ee Br 8 n 8 8 E Es a 5 DC Isolator D D D D D D D D D D D D D D D D Enclosure B E le a ilk ase A 2 amp 9 Flo Flo Flo 6 5 1 5 5 5 3 3 3 3 1 3 3 3 5 3 3 4 83 amp elg 448 86 a 3 3 3 g lg olg EE o o o o o o o PV MODULES TEST SOCKETS DC ISOLATOR DC BREAKERS DOCUMENT WD3 1 5 E3 Murdoch TECH POLY MAX POWER 60W TECH BANANA INSULATED YES POLYAMIDE MANU TELERGON ZFV32x2 MANU ABB POLES 2 TU 8 POWER VOLTAGE 17 50 QTY 32 VOLTAGE 1000V MAX VOLTAGE 600V MODEL 2 0527200180065 5202 86 GANGED Enclosure A MANUF YINGLI MAX POWER CURRENT 3 43A MANU SCH TZINGER MAX
2. Fault Current Shunt o T 5 5 238 25 8 3 Telergon 8 Pole g 586 85 2 E 3 335 E 48 8 DC Isolator 8 g 8 8 8 15 20cm V i oo Array Current Shunts DC BREAKERS MANU BLUE SEA SYSTEMS POLES 1 EACH MODEL 7050 7052 7053 PERMISSABLE RATED CURRENT 3A 5A 7A OPERATING RATED DC VOLTAGE 32V DC TEMP 10C TO CHARACTERISTIC THERMAL 60C ONLY MANU ABB POLES 2 MODEL 2CDS272001R0065 S202MB6 10 GANGED RATED CURRENT 6 0A 10 0A ACROSS 2 RATED DC VOLTAGE 125V POLES ONLY CHARACTERISTIC CURVE B m Murdoch DOCUMENT WD3 2 6 UNIVERSITY Author Kieran Peters Date 10 03 2015 Enclosure B Upper Wiring Level Wiring Diagram 99 APPENDIX DOCUMENT GD4 1 1 ENCLOSURE CONTROL PANEL GRAPHIC Murdoch W UNIVERSITY CONTROL PANEL A uum ge Battery Bypass AB Bypass CD Module A Module B Module C Module D Svst DC Isolat MPPT Load Switch Breaker Breaker Breaker Breaker Breaker Breaker ystem soon Connection Module A Breaker Module B Breaker Module C Breaker Module D Breaker DOCUMENT GD4 1 1 Enclosure A Bypass Experiment Grap
3. 23 TABLE 3 DETAILED DESIGN FACILITY PHYSICAL DIMENSIONS unsssesssnsssennsessseennnsennsesnnnennnsnnnsennnsunnnnnunnennnenn 27 TABLE 4 SPI SUN SIMULATOR RESULTS FOR PV 8 0 60000 1 50 TABLE 5 PARAMETER COMPARISON FOR PHOTOVOLTAIC MODULES ONE AND 60 VII VI LISTOFSYMBOLS A A Ampere C Degree Celcius a Temperature coefficient of Current D 2 Degree plane angle H Hz Hertz K kg Kilogram kW Kilowatt M mA Milliampere m Square meter N Nec Module efficiency 0 Ohm P K Temperature coefficient of Power V V Volts Temperature coefficient of Voltage W Watt VIII LIST OF ABBREVIATIONS A D d c E ELV Imp Isc IV LV MPP MPPT Pmax PV STC TC VMP VOC Wp Alternating current Direct current Extra low voltage Maximum power current Short circuit current Current Voltage characteristic Low voltage Maximum power point Maximum power point tracker Maximum Power Photovoltaic Standard test conditions 1000Wm2 ETC Temperature coefficient Maximum power voltage Open circuit voltage Peak wattage IX This page is intentionally left blank CHAPTER 01 INTRODUCTION 1 1 Project Introduction The Photovoltaic Array Troubleshooting and Educationa
4. 8 82 8 8 82 82 3 sockets not 5 amp amp 5 S 5 a a DC Isolator required but potentially useful B BIBIBIBIBIBIBIBIBIBIB BIB BIB D D D D D D D D D D D D D D D D Enclosure B E amp amp amp amp e g E E 2 E E g E g 2g g g g E 2 ie ls sis se sis s f ele elf elg 5 gt gt gt gt gt gt gt gt gt gt gt gt gt gt gt PV MODULES TEST SOCKETS DC ISOLATOR DC BREAKERS m Murdoch DOCUMENT WD3 1 6 TECH POLY MAX POWER 60W TECH BANANA INSULATED YES POLYAMIDE MANU TELERGON ZFV32x2 MANU ABB POLES 2 QTY 8 MAX POWER VOLTAGE 17 5V QTY 32 MAX VOLTAGE 1000V MAX VOLTAGE 600V MODEL 2CDS272001R0065 5202 86 GANGED Enclosure MANUF YINGLI MAX POWER CURRENT 3 43A MANU SCH TZINGER MAX CURRENT 32A MAX CURRENT 32A RATED CURRENT 6 0A ACROSS 2 Author Kier n Peters Upper Wiring Level MODEL YLP60Wp OPEN CIRCUIT VOLTAGE 22 0V MODEL SEB 6445 X PERMISSABLE OPERATING PERMISSABLE OPERATING RATED DC VOLTAGE 125V POLES ONLY Date 12 03 2015 Wiring Diagram 4 MODULES IN SERIES SHORT CIRCUIT CURRENT 3 8A CATEGORY CAT Ill TEMPERATURE 25 80 TEMPERATURE 40 TO 45C CHARACTERISTIC CURVE B 96 APPENDIX L DOCUMENT WD3 2 4 ENCLOSURE B LOWER WIRING LEVEL WIRING DIAGRAM MODEL YLP60Wp 4 MODULES IN SERIES am PV MODULES TECH
5. Enclosure A Bypass Experiment Graphic Author Kieran Peters p incl Student Access Points Date 10 03 2015 Appendix Figure 6 2 Preliminary design for Control Panel A 89 APPENDIX DOCUMENT GD3 2 8 PRELIMINARY DESIGN FOR CONTROL PANEL DC Circuit Breakers Master Switch 1111 11 5 Controller Vietron Energy MPPT100 50 Victron Energy 120Ah Battery Recommended Optional 1 Somv 50 50 50 Current Shunt 4 Current Shunt Student 9 Accessible Low Volt Loads 5 Banana 2 Sockets i Or Var Load Fault Switch Faults shown recommended configuration but are reconfigurable by tutor Murdoch UNIVE DOCUMENT WD3 2 8 Enclosure B Author Kieran Peters Reverse Current Experiment Graphic Date 10 03 2015 incl Student Access Points Appendix Figure 6 3 Preliminary design for Control Panel B 90 APPENDIX H SUITABILITY COMPARISON FOR REVISED PHOTOVOLTAIC MODULE SELECTION Panel Length Panel Width Fittings Length Proposed Array Width Proposed Array Length Angle Angle Array Width x Array Height y Min Pivot Height Angle Angle Array Width x Array Height y Min Pivot Height Angle Angle Array Width x Array Height y Min Pivot Height 660 mm 630 mm 160 mm 2140 mm 1890 mm 5 degrees 0 08727 radians 2132 mm 187 mm
6. OrderComponents 20 1144 26 11 14 Receive Components 27 11 14 15 01 15 Construct Facility 19 0145 4 05 15 NE Construct Frame 19 01 15 16 03 15 NE 7 Construct Array 19 0145 16 03 15 H Construct Wiring Loom 19 01 15 26 02 15 Construct Shading M 2 02 15 12 02 15 Meet Supervisors 18 0345 23 03 15 TEA DE ae 9 Assemble amp PaintFa 25 03 15 4 05 15 M Progress Report 131044 13 1174 N DE TIEREN EN Meet Supenisors 13110114 16 10 14 ATW EEUU UU Write Progress Report 20 10 14 5 11 14 E 9 Submit Progress Rep 13 11 14 13 11 14 Final Report 171114 22106 15 9 WriteFinalReport 17 11 14 9 04 15 Meet Supervisors 6 05 15 11 05 15 I I ReviseFinalReport 13 05 15 18 06 15 SubmitFinalReport 22 06 15 22 06 15 TE 9 Seminar Presentation 13 05 15 15 06 15 Write Presentation 13 05 15 11 06 15 Give Seminar Presen 15 06 15 15 06 15 H Appendix Figure 6 1 Gantt chart schedule for project development 88 APPENDIX F DOCUMENT GD3 1 8 PRELIMINARY DESIGN FOR CONTROL PANEL BANANA BANANA SOCKETS SOCKETS Master Switch Battery Charge Controller Victron Energy MPPT10D SO Victron Energy 120Ah Battery 50A Current Shunt Student Accessible Sar na Sockets Low Volt Loads Or Var Load n Murdoch DOCUMENT GD3 1 8 UNIVERSITY E
7. parallel strings required for each experiment tt ott 2 dh Modul Module Module Module D Earth BPD Switch Bank Telergon 8 Pole solator 2PoleDC Breaker 2Pole DC Breaker 2Pole DC Breaker 2Pole DC Breaker 2Pole DC Breaker 2Pole DC Breaks s Enclosure B Module Earth T Module Module SPD Con Pt Con Pt Con Pt 77 Con Pt SPD Con Pt Con Pt 8 0 Con Pt 35 Con Pt Module Module Module PV MODULES TEST SOCKETS DC ISOLATOR DC BREAKERS m Murdoch DOCUMENT WD3 1 6 TECH POLY MAX POWER 60W TECH BANANA INSULATED YES POLYAMIDE MANU TELERGON ZFV32x2 MANU ABB POLES 2 E QTY 8 MAX POWER VOLTAGE 17 5V QTY 32 MAX VOLTAGE 1000V M
8. 22 58 V Isc 3 80 362 3 52 362 3 64 362 3 63 362 363 363 Fill Factor 0 72 0 76 0 76 0 75 0 75 0 75 075 0 75 0 75 0 76 Rseries 0 662 0 635 0 712 0 701 0 668 0 634 0 628 0 680 0 654 712 1122 766 1091 455 771 479 1065 766 50 5 1 1 MAXIMUM MODULE POWER maximum power provided by a cell is achieved at a point on the IV characteristic where the product IV is at a maximum 7 The maximum module power parameter is worthwhile considering for any real world photovoltaic installation as this serves to indicate the best case scenario peak power output of a photovoltaic module A good photovoltaic system design will aim to operate the modules at peak power and therefore maximise return on project investment across the life of the system The maximum module power is not of pivotal importance for the PV Array Troubleshooting and Educational Facility as long as the voltage and current at the point of maximum power meet minimum requirements and do not exceed any project safety limitations Pmax 63 00 62 50 59 50 1 2 3 4 5 6 7 8 9 PV Module Identification Number Maximum Power W o P BON uw Figure 5 1 Maximum power comparison between modules Figure 5 1 shows a comparison of the maximum power produced by each of the nine available photovoltaic modules It should be
9. Hunt Fundamentals of photovoltaic modules and their applications United Kingdom Royal Society of Chemistry The 2010 S E International Photovoltaics Design and Installation Manual United States Solar Energy International 2004 Standards Australia AS 5033 Installation and safety requirements for photovoltaic PV arrays ed SAI Global Limited 2014 D S Dolan L Friedman J Huff and T Taufik Solar trainer for laboratory photovoltaic systems education in North American Power Symposium NAPS 2012 2012 pp 1 6 Amatrol Solar PV Troubleshooting Learning System vol 6552 B ed Jeffersonville Indiana Amatrol 2010 G Broun Detailed KP Thesis Design Render ed 2014 B o Meteorology Lowest Temperature for Jandakot Aero BoM Ed ed 2015 Yingli YL60Wp Data Sheet Y Energy Ed 20070824 03 Rev01 E ed Yingli 2007 Schletter Professional Solar Mounting Systems Mounting and Project Planning ed schletter de Schletter GmbH 2012 h N Unknown Panel Mounting ed flickr 1080 flickr handle 2011 Standards Australia AS 2756 Low voltage switchgear and controlgear Mounting rails for mechanical support of electrical equipment ed SAI Global Limited 1997 Standards Australia AS 3000 Wiring Rules ed SAI Global Limited 2007 S Solar Spi Sun Simulator 5600 SLP System Operation and Maintenance Manual Edition C ed Spire Solar 2012 S Solar Spi Sun Simulator 5600SLP Revis
10. 16 the experiments required can actually be performed using available components A simple legal feasibility assessment was conducted to ensure the experiments could be conducted whilst still adhering to all legal requirements of Australian Standards found in the research stage A basic economic feasibility test was then conducted to compare an estimated cost of the system to commercially available systems any differences were identified and explored Once system feasibility was established a short design requirement analysis was conducted The purpose of this analysis was to remove requirement conflicts and confirm client expectations Facility usage and storage locations and transit paths were examined to ensure the system complied with all expected client usage patterns while maintaining system longevity and usability Once all relevant design requirements were confirmed and all conflicts resolved a preliminary design was generated This design phase involved the use of tactile design tools such as whiteboard diagrams and pen to paper sketching of the facility frame wiring and PV module placement This progressed to design using software tools predominantly Google Sketch Up and Microsoft Visio as these tools were readily available The preliminary designs naturally progressed to a detailed design stage During the detailed design software tools such as Microsoft Visio were used to produce detailed wiring diagrams and sketches an
11. Meet all relevant Standards Conceptualisation e Brainstorming Discussions Component Research Personal Experience Preliminary design e Paper Whiteboard Sketches Google Sketch up Basic wiring diagrams Frame and component layout Feasibility Analysis e Technical feasibility Basic legal feasibility Economic feasibility Real component availability Detailed design Microsoft Excel Visio e Detailed Sketches eStrict dimensions declared Materials and components chosen Figure 3 1 Project design approach flowchart Research was undertaken to determine the minimum requirements of Australian Standards relevant to the Facility to survey existing PV education teaching systems and to determine the range of available components and parts that may be used within the facility Following the successful completion of the research stage a conceptualisation stage was undertaken to generate concepts and ideas for the system design This stage represents a significant creative design phase in the project where a reasonably unstructured process occurred Brainstorming and sketches were used to assist the formation of ideas coupled with a certain amount of component research to ensure generated concepts were reasonable Based on the initial research and conceptualisation a simplified feasibility analysis was conducted A short technical feasibility assessment was conducted to determine whether or not
12. Module operating parameters declared and environmental stimuli accounted for module operation at minimum expected temperatures was determined and considered as the maximum array voltage for system design as per AS5033 4 2 27 PV Array Max Voltage Voc array Yv Tmin PV Array Max Voltage 18 40 0 0037 18 40 3 4 25 M PV Array Max Voltage M20 34 Volts where Tmi is the lowest minimum temperature measured at the nearby Jandakot Aero site 13 5 8 kilometres away and M is the number of modules in series 14 Therefore the maximum number of series modules under ELV would be five This series restriction required that no more than five modules be made available to students for connection in series clearly it would not be feasible to deliver the unprotected terminals for all eight modules to the student user It was decided to provide two separate control panels for two mutually exclusive experiment platforms Enclosure A shown in Figure 3 7 would present four individual modules for series parallel and bypass experiments with all available module connection terminals presented in such a way that students could measure current flows around modules using handheld multimeters Enclosure B shown in Figure 3 8 would present a hard wired array containing four strings of two series modules each connected in parallel on the negative rail but not the positive rail such that an operator could select the number of
13. are included in APPENDIX I APPENDIX J and APPENDIX as a three layer set of plans for ease of viewing j Murdoch e sd CONTROL PANEL B Figure 3 7 Control Panel A experiment platform an Larger image shown in APPENDIX Figure 3 8 Control Panel B experiment platform Larger image shown in APPENDIX Wiring Enclosure B was designed to receive a pass through of array terminals from Enclosure A configure the array of modules as four parallel strings of two series modules with a hard wired connection on the negative array parallel node and provide string terminals to Control Panel B These terminals were provided to Control Panel B through a load breaking d c isolator string overcurrent protection breakers and terminated in the same insulated banana sockets as Control Panel A A current shunt connection is available for current measurements on the negative rail of the array that shall permit a student to measure net array current flow to a load using handheld digital multimeters A secret array of banana sockets would also be installed 29 behind Control Panel connected to every node on the array to provide a bank of connection poin
14. experiments from the Murdoch University Renewable Energy Engineering major can now be conducted in greater detail on a full array of modules while exposing students to industry standard components and techniques The Facility is also available for open days and promotions and shall be used to attract new students to the industry the school and generate a greater enthusiasm for solar power generation Already this project has been shown in the draft PV in Australia 2014 report from the Australian Photovoltaic Institute and it is hoped that other opportunities will be found in the future to showcase this example of Murdoch University student design innovation and discovery 74 6 2 Recommendations for Future Works A number of opportunities for future work exist outside the scope of this project One would suggest these works in the format of undergraduate engineering honours thesis and undergraduate engineering technician project opportunity descriptions e Develop a full range of undergraduate student experiments for photovoltaic module basics including series parallel configurations string fault scenarios parallel fault scenarios and earth fault situations e Interface the Facility earth bus with the installation earth of the Engineering Building 220 or the external lightning protection system on said building Permit true earth fault currents to flow in a safe manner and expand the range of fault scenario experiments available to
15. 5 1 6 MODULE FILL FACTOR The fill factor or curve factor is a measure of sharpness of the knee in an IV curve It indicates how well a junction was made in the cell and how low the series resistance has been made It can be lowered by the presence of series resistance and tends to be higher whenever the open circuit voltage is high 7 A simple relationship for fill factor is defined as follows The fill factor is the actual maximum power divided by the hypothetical power obtained by multiplying the open circuit voltage by the short circuit current 21 P Vuaxl _MAX_ _ MAX Voclsc 56 Fill Factor 77 0 76 5 76 0 75 5 75 0 74 5 74 0 73 5 1 2 3 4 5 6 7 8 9 PV Module Identification Number Figure 5 6 Fill Factor comparison between PV modules The fill factor was largely irrelevant for this project provided all modules conformed approximately to the data sheet specified value In general the fill factor was at or greater than the data sheet specified 72 indicating that the cell junctions were likely to be well made The comparison of fill factor ratings is shown graphically in Figure 5 6 5 1 7 MODULE SERIES RESISTANCE The series resistance of a photovoltaic module is a representation of the innate resistance measured across a module and is dependent on a number of elements Rs Rep Rgp Ren Ren where Rcpis the metal contact to p type semiconducto
16. CLAMP 12 00 SolarMatrix Part MF11160 nn EPDM RUBBER SEAL 000 10 SolarMatrix Part MF11272 1 roll BATTERY 120 1 00 SolarMatrix Part BAT22120 111 SYSTEM SHUTDOWN LABEL Lo EE Solaran Fall DASIDA ___ SOLAR WIRING LABEL SD aaen PV SWITCH DISCONNECTOR 1 00 4 MALE CABLE COUPLER 4 00 MC 4 FEMALE CABLE COUPLER 6 00 4 FEMALE CABLE RECEPTACLE 8 00 8 POLE DC ISOLATOR 1 00 GROUNDING LUG 10 00 PV MODULE 9 00 DC CIRCUIT BREAKER 1 00 DC CIRCUIT BREAKER 1 00 DC CIRCUIT BREAKER 1 00 112
17. Kieran Peters or Yes able to be purchased on behalf of Murdoch University where required Machining and Welding Skills and Tools Workshop and Skills provided by Yes technical officer Mr John Boulton Electrical Component Cabling and Tools and Skills provided by Mr Kieran Yes Equipment Installation Skills and Tools Peters technician Mr lafeta Laava and technical officer Mr john Boulton licenced electrician Site Suitability determination Skills and Tools provided by Murdoch University Yes Tools Skills provided by Mr Kieran Peters 23 3 1 4 2 ECONOMIC FEASIBILITY A simple economic feasibility study was conducted to ensure the Facility would provide positive economic benefits to Murdoch University exceeding the cost of design components construction and testing Positive benefits included the availability of an entirely new teaching tool providing a greatly enhanced learning experience for students when compared to existing tools as well as enhanced promotion capabilities available to Murdoch University for attracting new students to relevant courses Project costs were limited to component purchases as individuals undertook this project on a volunteer basis This feasibility analysis section was not exhaustively completed it quickly became apparent that the positive difference between project costs to Murdoch University and economic benefits obtained from a completed Facility was an order of magnitude g
18. POLY MAX POWER 60W QTY 8 MAX POWER VOLTAGE 17 5V MANUF YINGLI MAX POWER CURRENT 3 43A OPEN CIRCUIT VOLTAGE 22 0V SHORT CIRCUIT CURRENT 3 8A TEST SOCKETS TECH BANANA QTY 32 MANU SCH TZINGER MODEL SEB 6445 NI X CATEGORY CAT III INSULATED YES POLYAMIDE MAX VOLTAGE 1000V MAX CURRENT 32A PERMISSABLE OPERATING TEMPERATURE 25C 80C Enclosure A 10cm Earth Fault 1 Earth Fault 2 Earth DC ISOLATOR MANU TELERGON ZFV32x2 MAX VOLTAGE 600V MAX CURRENT 32A PERMISSABLE OPERATING TEMPERATURE 40C TO 45C 40 50cm Fault Switch DPST am DC BREAKERS DC Isolator Pe MANU BLUE SEA SYSTEMS POLES 1 EACH MODEL 7050 7052 7053 PERMISSABLE i RATED CURRENT 3A 5A 7A OPERATING DC VOLTAGE 32V DC TEMP 10C TO SU nennen 25 CHARACTERISTIC THERMAL 60C ONLY MANU ABB POLES 2 MODEL 2 0527200180065 5202MB6 10 GANGED RATED CURRENT 6 0A 10 0A ACROSS 2 All Metal RATED DC VOLTAGE 125V POLES ONLY eta PRIEST EE CHARACTERISTIC CURVE B Parts t t t t t t t t t u 5 5 8 3 5 8 8 5 5 3 DOCUMENT WD3 2 4 Murdoch WF UNIVERSITY Enclosure B Author Kieran Peters Lower Wiring Level Date 10 03 2015 Wiring Diagram 97 APPENDIX DOCUMENT WD3 2 5
19. Tutor configures fault ti ault connections dum DC BREAKERS Earth MANU BLUE SEA SYSTEMS POLES 1 EACH MODEL 7050 7052 7053 PERMISSABLE RATED CURRENT 3A 5A 7A OPERATING RATED DC VOLTAGE 32V DC TEMP 10C TO CHARACTERISTIC THERMAL 60C ONLY MANU ABB POLES 2 MODEL 2CDS272001R0065 S202MB6 10 GANGED RATED CURRENT 6 0A 10 0A ACROSS 2 RATED DC VOLTAGE 125V POLES ONLY CHARACTERISTIC CURVE B DOCUMENT WD3 2 5 m Murdoch UNIVERSITY Author Kieran Peters Date 10 03 2015 Enclosure B Middle Wiring Level Wiring Diagram 98 APPENDIX N DOCUMENT WD3 2 6 ENCLOSURE B UPPER WIRING LEVEL WIRING DIAGRAM MODEL YLP60Wp 4 MODULES IN SERIES PV MODULES TECH POLY MAX POWER 60W 8 MAX POWER VOLTAGE 17 5V MANUF YINGLI MAX POWER CURRENT 3 43A OPEN CIRCUIT VOLTAGE 22 0V SHORT CIRCUIT CURRENT 3 8A TEST SOCKETS TECH BANANA QTY 32 MANU SCH TZINGER MODEL SEB 6445 NI X CATEGORY CAT Ill INSULATED YES POLYAMIDE MAX VOLTAGE 1000V MAX CURRENT 32A PERMISSABLE OPERATING TEMPERATURE 25C TO 80C DC ISOLATOR MAX VOLTAGE 600V MAX CURRENT 32A TELERGON ZFV32x2 PERMISSABLE OPERATING TEMPERATURE 40C TO 45C DC Breakers 15 20cm Load
20. Voltage curves for mismatched PV modules 2 1 6 BYPASS DIODES As with any series connected circuit the element with lowest current defines the total current 4 Since defects or shading on photovoltaic cells can impair current flow on strings a method to avoid the negative impacts defects associated with some cells on the performance of the rest of the string Bypass diodes are wired in parallel with photovoltaic modules to divert current around in the event of partial or complete module shading 8 Bypass diodes are important for modules wired in series where the addition of these diodes can avoid throttling the string current production to that permitted by the worst shaded module In typical thirty six cell crystalline photovoltaic modules two bypass diodes are installed across different strings of cells typically each diode shall service eighteen cells so that in the event of partial shading the module could continue to contribute some current to the string as per usual 11 Photovoltaic System Regulations Research Photovoltaic systems are not exempt Australian Standards regulations for system design installation and usage The Facility is no exception to this two primary Standards documents are applicable to the system AS5033 of 2014 regarding installation and safety requirements specific to photovoltaic arrays and AS3000 of 2007 the standard wiring bible document of wiring rules relevant to any electrical system for us
21. allow for maximum expansion contraction under expected operating temperatures Mounting frames and other 77 methods used for attaching modules to frames shall be made from corrosion resistant materials suitable for the lifetime and duty ofthe system e g aluminium galvanised steel or H3 treated timber Care shall be taken to prevent electrochemical corrosion between dissimilar metals On a related note AS5033 4 3 requires that all equipment exposed to the outdoor environment shall be at least IP54 compliant and shall be UV resistant AS5033 3 2 specifies that all wiring shall be installed in accordance with AS3000 2007 Protection against electric shock by means of double or reinforced insulation shall be required for all LV systems but no specific directives for ELV are specified In general because of the risk of d c arcs double insulation is recommended where possible to make the installation as inherently safe as possible As such double insulation cables should be installed for all Facility parts exposed to student interaction AS5033 3 3 provides directives regarding protection against overcurrent in the Facility Faults are described as a potential source of overcurrent and may occur as a result of short circuits within modules junction and combiner boxes module wiring or earth faults from array wiring Semiconductor solid state devices shall not be used for overcurrent protection purposes 9
22. array for creating fault situations To other frames and metal parts include banana plugs for creating fault connections To other strings To internal module connection To internal module m connection lt A WE k noH Current meter connection possibility or banana A plugs so that connections can be made to any point in the array for creating fault situations gt 87 APPENDIX E GANTT CHART SCHEDULE FOR PROJECT DEVELOPMENT gt GANTT A 5 A 2014 2015 PO Name ae End date Aug Sep Oct Nov Dec Jan Feb Mar May Jun Jul Project Plan 21 07 14 14 08 14 Meet Supervisors 21 07 14 31 07 14 Determine Project Ta 28 07 14 4 08 14 9 Develop Gantt Chart 6 08 14 6 08 14 i 9 Write Project Plan 708 14 13 08 14 9 Submit ProjectPlan 14 08 14 14 08 14 Design Facility 18 0844 9 10 14 7 Design Array 18 08 14 9 10 14 H Design Wiring 18 0844 9 40 44 Design TestPoints 18 08 14 9 10 14 Design System Frame 18 0844 9 10 14 Design Shading Tech 18 09 14 NEE Redesign Facility 134044 19 11 14 Redesign Array 13110114 13 11 14 Redesign Wiring 1341044 19 11 14 Redesign Test Points 13 10 14 19 11 14 Redesign System Fra 13 10 14 13 11 14 Redesign Shading T 13 11 14 13 11 14 ComponentSourcing 20 11 14 15 01 15
23. could be manually actuated to halt current flow in the event of an isolator failure 30 Cables connectors were sized accordance with AS5033 4 3 with regard to overcurrent protection ratings the maximum normal operating current and the prospective fault current Derating factors were specified by some manufacturers given the expected elevated operational temperatures of the system However the only available industry standard multi stranded cables with suitable temperature and UV ratings were well oversized for these requirements so the smallest of these over rated sizes was selected being HIKRA PV array cables at a cross sectional area of 6mm2 Red coloured insulation was specified on active conductors from the positive terminals of each module and black for the return negative terminals this colour coordination would be continued throughout each wiring enclosure Industry standard MC 4 connectors were specified for each array cable connectors are not required by AS5033 9 but were designed nonetheless to permit modules to be removed for maintenance repair or PV MODULES TECH POLY MAX POWER 60W Qrv 8 MAX POWER VOLTAGE 17 5V MANUF YINGLI MAX POWER CURRENT 3 43A MODEL YLP60Wp OPEN CIRCUIT VOLTAGE 22 0V 4 MODULES IN SERIES SHORT CIRCUIT CURRENT 3 8A TEST SOCKETS TECH BANANA INSULATED YES POLYAMIDE QTY 32 MAX VOLTAGE 1000V MANU SCHUTZINGER MAX CURRENT 32A MODEL SEB 6445 PERMIS
24. electrical appliances and equipment to be supplied 18 The installation shall be divided into circuits as necessary to avoid danger and minimise inconvenience the event of a fault and facilitate safe operation inspection testing and maintenance 18 AS3000 1 7 requires that electrical equipment shall be selected and installed to operate in a safe and reliable manner in the course of normal operating conditions and not cause danger from electric shock fire high temperature or physical injury in the event of reasonably expected conditions of abnormal operation overload fault or external influences that may apply in the electrical installation and be installed in accordance with the manufacturer s instructions 18 Equipment is deemed to satisfy this requirement if it satisfies the essential safety requirements of AS3820 or other appropriate Australian Standard Any equipment installed shall be subject to reasonable inspection and verification upon installation alteration addition or repair prior to being placed in service or use to confirm that the installation meets all requirements of AS3000 as applicable AS3000 1 4 provides several definitions an understanding of which is crucial for a complete understanding of the project scope and for the Facility to meet the minimum legal requirements Relevant definitions are as follows Extra low voltage Not exceeding 50V a c or 120 V ripple free d c 18
25. glass frame sealing back contact back foil laminate Figure 2 4 Cross section of typical crystalline laminated photovoltaic module A hardened or tempered glass layer typically with anti reflective coating permits photons to strike the PV cells while protecting the cells from damage An encapsulant typically ethyl vinyl acetate EVA surrounds the cells and forms an airtight layer 7 Electrical conductors run from cell to cell and connect the internal circuit of the module The strings of conductor connected cells are terminated in a junction box that permits connections to the load to be made and houses any bypass and blocking diodes that may be installed A plastic laminate layer such as Tedlar 7 may be used on commercial modules to provide support for the cells from behind Modules are typically assembled as a string of photovoltaic cells Many crystalline modules commercially available today contain 36 cells in series to produce voltages high enough to charge 12V batteries 2 1 4 SHADING EFFECTS ON CRYSTALLINE PHOTOVOLTAIC MODULES Shaded or partially shaded crystalline photovoltaic modules do not produce rated maximum current or power A shaded photovoltaic cell experiences reduced current flow with current reducing proportionally as shading increases until the cell is completely shaded and no current may flow As series strings of cells are limited to the lowest current cell 4 partial shading of a mo
26. junction current is 7 e V IRs V IRs Ras where e Rcpisthe metal contact to p type semiconductor resistance For a good solar module the shunt resistance should be very large to minimise uncontrollable internal losses within each cell Figure 5 8 shows that all modules exhibit a shunt resistance in excess of 4500 and should resist an acceptable amount of internal module current flow for the experiments required by the Scope of this project It is notable that potential exists for a comparison between modules with high and relatively low shunt resistance on the Facility and this may provide opportunity for a greater range of student experiments than originally required to facilitate this the four modules presented on Control Panel A Modules 1 3 4 and 5 were chosen to show a range of available shunt resistances 59 5 1200 1000 800 60 4 0 1 2 3 4 5 6 7 8 PV Module Identification Number Shunt Resistance Figure 5 8 Shunt resistance comparison between modules 5 2 Selection of Spare PV Module The Facility required only eight photovoltaic modules to meet the scope of the project but nine modules were purchased to provide Murdoch University with one spare unit The spare module could be swapped with any unit on the Facility if one were to suffer damage or be used to perform small scale induction experiments on the same model module as u
27. noted that although the peak power produced by each module varies considerably such variances mainly within the 3 tolerance 14 listed on the module data sheets by manufacturer Yingli Two modules actually performed even better than this stated tolerance producing up to 4 2 greater than rated maximum power during tests 51 5 1 2 VOLTAGE AT MODULE MAXIMUM POWER The maximum power voltage of a PV module is the voltage across module terminals at which the module outputs the greatest power The voltage at maximum module power becomes important to a photovoltaic system designer when attempting to produce peak power using a number of modules in parallel A significant mismatch represents a discrepancy between peak power production areas of the IV curve between modules and could suggest that the modules have been poorly binned during production Vem 18 50 18 40 18 30 18 20 18 10 18 00 17 90 17 80 17 70 1 2 3 4 5 6 8 9 PV Module Identification Number Voltage at Maximum Power V Figure 5 2 Maximum power voltage comparison between PV modules The voltage at maximum module power was considered important for this project as an attempt was made to provide reasonably matched photovoltaic modules to students particularly for the experiments conducted using Wiring Enclosure A As these experiments deal with cases of current and voltage mismatching under normal and shaded conditions the introduction of extraneous dis
28. panel Each control panel was then installed in the relevant wiring enclosure using a hinge and secure wingnut connection and electrically connected to the wiring back plates The breakers and isolators were placed on a riser from the back plate to protrude through each control panel and provide isolation actuation to users and ensure these protection devices are accessible to the lay person in accordance with AS3000 2 1 2 D 18 4 2 7 FINAL SYSTEM ASSEMBLY Once all necessary components were assembled or custom built the entire Facility system could be put together and tested further The final system assembly stage required the removal of the photovoltaic array shaft to fit the tilt mechanism gearbox and subsequent reinstallation The finished build is shown in Figure 4 18 on site at Murdoch University Building 220 and can be favourably compared with the detailed design sketch in Figure 3 5 48 Figure 4 18 Completed facility on site at Murdoch Engineering Building 220 roof 49 CHAPTER 05 FACILITY TESTING 5 1 Module Testing Photovoltaic modules were individually tested using the newly assembled Spi Sun sun simulator located at Murdoch University The Spi Sun Simulator 560SLP system permits indoor testing of terrestrial photovoltaic modules using an upward facing illumination with spectrum closely matching the solar spectrum 19 The illumination systems produces a filtered light that simulates the spectrum observed aft
29. presumably to improve protection system reliability over the life of the Facility AS5033 3 3 2 requires that overcurrent protection be provided where required by manufacturers of PV modules and associated equipment or where the photovoltaic system is connected to batteries Said protection shall be installed in the form of either circuit breakers or fuses where batteries are installed the battery relevant protection as per AS5033 2 1 7 AS5033 3 3 3 requires that all overcurrent protection shall be capable of interrupting the maximum prospective fault current from the battery 9 AS5033 3 3 4 suggests that circuit breakers are not ideal for string overcurrent protection implying that replaceable fuses would be a better option String overcurrent protection shall also be used in all instances where the PV module maximum overcurrent protection rating is less than the product of the module short circuit current STC and the number of modules in the string minus one 54 1 Isc gt OCPR Overcurrent protection shall be sized accordance with AS5033 3 3 5 Each photovoltaic module string shall be protected with an overcurrent protection device where the nominal overcurrent protection rating of the string overcurrent protection device shall be In where 78 In gt 1 5 Isc Tn lt 2 4 Isc In lt 55033 3 3 6 determines that overcurrent protection for st
30. shown in Figure 4 8 Cables connecting the photovoltaic modules to the wiring enclosures are potentially exposed to weather solar radiation mechanical stress and student interference For this reason and to meet requirements of AS5033 all array cables were routed through ultraviolet resistant industry standard photovoltaic cable conduit secured primarily with aluminium saddles and reinforced using ultraviolet resistant cable ties Figure 4 9 shows the cable conduit routes being installed to minimise cable loops and therefore voltages induced by nearby lightning strikes as per AS5033 Array cable conduit was connected to Wiring Enclosure A through the base of the enclosure as per AS3000 Custom cable conduit glands Figure 4 10 were produced to accept the non standard size of photovoltaic cable conduit and module cables terminated on DIN rail connections within the enclosure Once array wiring was completed preliminary Facility testing could be conducted without using the control panels as shown in Figure 4 11 40 Figure 4 8 PV module cable loom measured and cut to size Figure 4 9 Array wiring routed through industry standard conduit to wiring enclosures 41 42 4 2 4 FACILITY ACCESSORY CONSTRUCTION Several accessories to the Facility were constructed that enhanced the quality of the system as a teaching tool These included basic orientation and level indicators hooks to store measurement and circuit leads on the c
31. that all d c cables should be installed so that positive and negative cables of individual circuits should be bundled together avoiding the creation of wiring loops in the system Wiring loops could result in a situation where voltages are induced in the Facility when lightning strikes locations nearby such as strikes upon the external lightning protection system on the Engineering Building 220 AS5033 4 2 specifies that the photovoltaic array maximum voltage shall be considered to be equal to Voc array corrected for the lowest expected operating temperature PV Array Max Voltage Voc array Yo Tmin Tstc M 79 where e Mis number of series connected modules in a string e Y is voltage temperature coefficient supplied by manufacturer 55033 4 3 Requires that all components installed in photovoltaic systems shall be rated for d c use have a voltage rating equal to or greater than the PV array maximum voltage and have a current rating greater equal to that shown in AS5033 Table 4 2 Additionally systems with voltages above 50 V d c shall include bypass diodes unless shading is not possible by design or location or unless the PV module manufacturer specifies not to use bypass diodes If PV modules are not internally fitted with bypass diodes they shall be fitted externally with a minimum of one per PV module 9 Circuit breakers shall be certified to either AS60898 2 or IEC60947 2 not polarity sensitive rat
32. to operate and as student proof as practicable Key assumptions are outlined below 1 Laboratory instructors and technicians operating or maintaining the Facility shall have a working understanding of photovoltaic modules arrays protection devices and configurations 2 Laboratory instructors and technicians shall not cause the total voltage available to students to exceed 120V ripple free d c at any time This can be achieved by never permitting a series connection of more than five modules Instructors shall not make the internal electrical connections of the facility available to students 3 Students using the Facility shall have a basic understanding of the theory behind photovoltaic modules solar geometry electrical circuits and circuit measurements data 32 logging over current protection devices and shall obey all reasonable instructions warning signage Students using the Facility shall undergo a simple induction before attempting to use the Facility unsupervised The Facility may be left in direct sunlight and rain for weeks at a time but the primary storage location shall be indoors When possible the Facility shall be stowed before it could be affected by extreme wind or weather events The Facility shall be used within a 100km range of Perth Western Australia and is therefore unlikely to be exposed to significant levels of solar radiation at temperatures below freezing This geographical limitation ha
33. torqued appropriately 15 This has the result of electrically connecting all module frames together for earthing purposes and subsequently reduces the required length of cable for earth connections 37 steel A frame was constructed to support the array permit rotation while providing mounting opportunities for other hardware The frame was built to be the maximum possible width and length permitted by the elevator design in Building 220 of Murdoch University Pneumatic caster wheels were installed on each corner to permit travel over mild bumps and gaps in pavement These wheels are shown in Figure 4 6 Two IP65 wiring enclosures pictured in Figure 4 7 were installed on the A frame each to house one of the two mutually exclusive experiment control panels Provisions were also installed for the A frame to carry a large battery and the winch motor with room remaining for a third potential experiment control panel enclosure Figure 4 6 Facility frame constructed with pneumatic caster wheels 39 Figure 4 7 Array mounted on facility frame using pillow block bearings 4 2 3 PHOTOVOLTAIC ARRAY WIRING INSTALLATION Three cables connected each module to the wiring enclosure These cables were coloured red for active black for return and blue for the bypass point connection Each module was routed separately to provide access to individual modules inside the wiring enclosures The wiring loom for array cables is
34. under various load conditions A short circuit between the midpoint of String AB and the negative terminal rail of the array shall be made by a tutor as shown in Figure 5 17 A student would measure the currents flowing through each string the fault connection and through a connection to the load These measurements would be used to determine the string impacted by this short circuit fault and whether or not overcurrent protection devices are likely to operate Upon completion of Sample Experiment 02 a student would have developed a greater understanding of simple faults on a photovoltaic array and some of the difficulties detecting faults in photovoltaic systems 67 String AB String CD Breaker String EF Breaker String GH Breaker MODULE B Figure 5 17 Equivalent circuit model diagram for Sample Experiment 02 5 3 2 2 EQUIPMENT REQUIRED e Facility Wiring Enclosure shown APPENDIX P 6DMMS UniT 240V DMMs were used e Handheld DMM wired to Irradiance Sensor on Facility e Shading device 5 3 2 3 SAFETY REQUIREMENTS The experiment involved electrical connections with voltages up to 46V d c and currents up to 15 A It is noted in AS5033 2 1 8 that the fault current depends on the number of strings the fault location and the irradiance level This makes short circuit detection within a PV array very difficult Electric arcs can be formed in a PV array with fault currents that
35. 4 FACILITY CONSTRUCTION 4 1 Component Acquisition 4 2 System Construction 4 2 1 PV Module Preparation 4 2 2 Photovoltaic Array Frame Construction 4 2 3 Photovoltaic Array Wiring Installation 4 2 4 Facility Accessory Construction 4 2 5 Wiring Enclosure Assembly 4 2 6 Control Panel Construction 4 2 7 Final System Assembly CHAPTER 05 FACILITY TESTING 5 1 Module Testing 5 1 1 Maximum Module Power 5 1 2 Voltage at Module Maximum Power 5 1 3 Current at Module Maximum Power 5 1 4 Module Voltage at Open Circuit 5 1 5 Module Current at Short Circuit 5 1 6 Module Fill Factor 5 1 7 Module Series Resistance 5 1 8 Module Shunt Resistance 5 2 Selection of Spare PV Module 16 16 17 18 20 20 25 26 32 32 34 34 34 34 36 40 43 44 46 48 50 50 51 52 53 54 55 56 57 59 60 5 3 Practical Experiment Results 5 3 1 Sample Experiment 01 Bypass Current Observation 5 3 2 Sample Experiment 02 String Fault Analysis CHAPTER 06 CONCLUSIONS AND RECOMMENDATIONS 6 1 Project Conclusion 6 2 Recommendations for Future Works WORKS CITED IX APPENDICES 62 62 67 74 74 75 76 77 IV LIST OF FIGURES FIGURE 1 1 PHOTOGRAPH OF FACILITY AND CONTROL PANEL AS PICTURED IN THE PV IN AUSTRALIA REPORT 2014 1 eessssssssssssssssesssssessssesssseesssasesssneesssneeessneesssseesssseesssesssseesssueanssseassnsearsnsearsnseersnseessnsersnseessnsess 1 FIGURE 1 2 DOCUME
36. 47 771 198 479 205 1065 08 766 381 Pmax 62 1453 60 7991 60 7496 61 3904 61 2511 61 1094 61 1667 61 7307 62 515 Vpm 18 2128 18 403 17 9683 18 0689 18 0829 17 9881 18 1423 18 1396 18 3954 Ipm 3 41217 3 30376 3 38092 3 39757 3 38724 3 3972 3 37149 3 40309 3 3984 Fill Factor 0 76054 0 7646 0 7472 0 75374 0 75408 0 754 0 75273 0 75382 0 76197 Active Eff 11 0657 10 826 10 8172 10 9313 10 9065 10 8813 10 8915 10 9919 11 1316 Aperture Eff 3 82762 3 74471 3 74166 3 78113 3 77255 3 76382 3 76735 3 80208 3 8504 Segment 156 156 156 156 156 156 156 156 156 Area Segs in Ser 36 36 36 36 36 36 36 36 36 Segs in Par 1 1 1 1 1 1 1 1 1 Panel Area 16236 16236 16236 16236 16236 16236 16236 16236 16236 Frequency 274000 274000 274000 274000 274000 274000 274000 274000 274000 85 SweepDelay 10 10 10 10 10 10 10 10 10 SweepLength 60 60 60 60 60 60 60 60 60 SweepSlope 0 025 0 025 0 025 0 025 0 025 0 025 0 025 0 025 0 025 MCCC2 1 0022 1 0022 1 0022 1 0022 1 0022 1 0022 1 0022 1 0022 1 0022 1 155 1 155 1 155 1 155 1 155 1 155 1 155 1 155 1 155 MCCC4 1 155 1 155 1 155 1 155 1 155 1 155 1 155 1 155 1 155 Lampl 100 035 99 9878 99 9956 99 9753 100 017 100 019 100 039 100 04 99 9951 IntV 5 94087 5 94087 5 9412 5 9412 5 9412 5 9412 5 9412 5 9412 5 94087 IntV2 6 04186 6 04186 6 0422 6 0422 6 0422 6 0422 6 0422 6 0422 6 0422 IntV3 5 9427 5 942
37. 5 1 5 MODULE CURRENT AT SHORT CIRCUIT The current in the circuit when a short is placed across the photovoltaic module terminals i e No load is described as the short circuit current Short circuit current is the light generated current or photo current IL 7 as shown in Figure 2 3 The short circuit current shares a direct relation to the number of photons of light being absorbed by the cell The short circuit current is therefore directly proportional to light intensity 21 The module current at short circuit is the highest current that the photovoltaic module can be expected to produce If a fault occurred to short between parts of the array the fault currents could potentially be equal to or much greater than the short circuit current of the components involved This parameter is important both for the Enclosure A experiments and the Enclosure B experiments on board the Facility In particular high Isc values were desirable for situations where poor sunlight may hamper fault current detection Figure 5 5 shows that most 55 photovoltaic modules produce similar current at short circuit with the exception of one unit Module 2 produced 3 3 less current at open circuit than the other modules Isc 3 66 3 64 3 62 3 60 3 58 3 56 3 54 3 52 3 50 3 48 3 46 3 44 1 2 3 4 5 6 7 8 9 PV Module Identification Number Current at Short Circuit A Figure 5 5 Short circuit current comparison between PV modules
38. 5 3 2 requires that a sign containing this text shall be attached to the photovoltaic array and string junction boxes WARNING HAZARDOUS D C VOLTAGE in black text on yellow background AS5033 5 5 2 Specifies that where multiple isolation devices are used the following text shall be displayed next to PCE WARNING MULTIPLE D C SOURCES TURN OFF ALL D C ISOLATORS TO ISOLATE EQUIPMENT AS5033 5 5 3 requires that all systems greater than 240W shall include a shutdown procedure that sets out steps to safely shut down the system placed adjacent to and visible from equipment to be operated in the event of a shutdown AS5033 5 7 requires that suitable documentation of the installed system must be included with the system 81 APPENDIX B AS3000 2007 REQUIREMENTS ANALYSIS AS3000 is an important document for the safety of people using and near to the Facility At all times AS3000 must be adhered to with explicit protection systems enforced wherever required or suggested by the Wiring Rules AS3000 1 6 specifies that any electrical installation shall be designed to protect persons livestock and property from harmful effects function correctly as intended minimise inconvenience in the event of a fault and facilitate safe operation inspection testing and maintenance for the life ofthe system Designers shall ensure that the voltage at the terminals of electrical appliances and equipment is suitable for the nominal operating voltage of
39. 7 5 9427 5 9427 5 9427 5 9427 5 9427 5 9427 5 9427 IntV4 5 9427 5 9427 5 9427 5 9427 5 9427 5 9427 5 9427 5 9427 5 9427 LoadV 5 39811 5 39811 5 39811 5 39811 5 39811 5 39811 5 39811 5 39811 5 39811 PulseWidth1 66 1605 66 0729 66 1021 65 927 66 66 1605 66 0292 66 0437 66 0437 PulseWidth2 65 9562 65 9854 66 1021 65 9708 66 0584 66 66 0146 66 0729 66 0437 PulseWidth4 0 0 0 0 0 0 0 0 0 TRef1 26 0934 26 0924 25 7587 25 6931 25 7704 25 8702 25 9378 25 9481 26 0386 TRef2 26 6523 26 7101 26 3764 26 4286 26 3881 26 4291 26 4378 26 4481 26 6563 MCMode FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE Irradiance2 100 166 100 158 100 177 100 178 100 176 100 178 100 176 100 177 100 176 IrrCorr2 70 70 70 70 70 70 70 70 70 LoadV2 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 PulseWidth12 66 1605 66 0729 66 1021 65 927 66 66 1605 66 0292 66 0437 66 0437 PulseWidth22 65 9562 65 9854 66 1021 65 9708 66 0584 66 66 0146 66 0729 66 0437 Irradiance3 100 107 100 106 100 117 100 118 100 116 100 116 100 116 100 116 100 117 IrrCorr3 40 40 40 40 40 40 40 40 40 LoadV3 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 PulseWidth13 66 1605 66 0729 66 1021 65 927 66 66 1605 66 0292 66 0437 66 0437 PulseWidth23 65 9562 65 9854 66 1021 65 9708 66 0584 66 66 0146 66 0729 66 0437 86 APPENDIX D Visio WIRING DIAGRAM CONCEPT FOR EXPERIMENT MEASUREMENTS Current meter connection possibility or banana plugs so that connections can be made to any point in the
40. 93 mm 55 degrees 0 95993 radians 1227 mm 1753 mm 876 mm 65 degrees 1 13446 radians 972 mm 2085 mm 1042 mm Product Identification Peak Power Technology Mass Manuf Tolerance Open Circuit Voltage Voc Short Circuit Current Isc MPP Voltage MPP Current Maximum Panels in Series 4 Parallel Pairs Max Available Voltage to Student Max Available Current to Student Max Voltage Per Terminal Output Max Current Per Terminal Output Fuses 1 5 x Isc In 5 7 lt In Minimum String Fuse Size Maximum String Fuse Size 4 Parallel Pairs Typical Available Voltage to Student Typical Available Current to Student Typical Voltage Per Terminal Output Typical Current Per Terminal Output Appendix Figure 6 4 Yingli 60W module suitability selection matrix 5 Modules 2 4 9 12 6A 10 A 91 Panel Length Panel Width Fittings Length Proposed Array Width Proposed Array Length Angle Angle Array Width x Array Height y Min Pivot Height Angle Angle Array Width x Array Height y Min Pivot Height Angle Angle Array Width x Array Height y Min Pivot Height 572 mm 680 mm 160 mm 1876 mm 2040 mm 5 degrees 0 08727 radians 1869 mm 164 mm 82 mm 55 degrees 0 95993 radians 1076 mm 1537 mm 768 mm 65 degrees 1 13446 radians 793 mm 1700 mm 850 mm Product Identification Peak Power Technology Manuf Tolerance 10 UP Open Circuit Vo
41. ANA PLUG YELLOW 15 00 FEMALE BANANA SOCKET BLACK Sch tzinger Part SEB 6445 NI SW 15 00 FEMALE BANANA SOCKET RED Sch tzinger Part SEB 6445 NI RT 34 00 FEMALE BANANA SOCKET YELLOW Sch tzinger Part SEB 6445 NI GE 109 FEMALE SOCKET BLUE 6 00 g CURRENT SHUNT i eee ES Componente ran 61053267 E EM 5200 6A 2 CURVE D BREAKER ES Consonants Part 745 T Ia EQUIPMENT CABLE 95 E a EQUIPMENT WIRE 2 5 GREEN YELLOW a mn sn EQUIPMENT WIRE 2 5MM RED ES Components Parc EQUIPMENT WIRE 2 5MM BLUE ES componente Par di 906 a A t d pee 1 00 Manufacturer Part 6A 2491X2 5 BK 100R PV CABLE RED 30 00 PV CABLE BLACK 30 00 PV CABLE BLUE 30 00 MC 4 MALE CABLE COUPLER ae 4 FEMALE CABLE COUPLER ara Part CA NCA FG04 MC 4 FEMALE CABLE a a on 110 MC4 OPEN END SPANNER 1 00 CABLE GLAND GREY 14 00 SolarMatrix Part EC2175 2 28 _ isn LOCKNUT 2 1400 ________ SolarMatrix EC217088G 1 00 1 00 1 00 1 00 1 00 MOUNTING RAIL 6 00 RAIL END CAP 12 00 MODULE END CLAMP 12 00 MODULE GROUNDING MID
42. AX VOLTAGE 600V MODEL 2CDS272001R0065 5202 6 GANGED Enclosure A MANUF YINGLI MAX POWER CURRENT 3 43A MANU SCH TZINGER MAX CURRENT 32A MAX CURRENT 32A RATED CURRENT 6 0A ACROSS 2 Peters Upper Wiring Level MODEL YLP60Wp OPEN CIRCUIT VOLTAGE 22 0V MODEL SEB 6445 X PERMISSABLE OPERATING PERMISSABLE OPERATING RATED DC VOLTAGE 125V POLES ONLY Date 12 03 2015 Wiring Diagram 4MODULESINSERIES SHORT CIRCUIT CURRENT 3 8 CATEGORY CAT III TEMPERATURE 25 80C TEMPERATURE 40C TO 45 CHARACTERISTIC CURVE Figure 3 6 Example of partial wiring diagram for Enclosure A Full diagrams available in APPENDIX I 28 Wiring Enclosure was designed to receive the array cables pass the terminals of four modules through a load breaking d c isolator and suitable overcurrent breakers and present these four modules on Control Panel A by means of voltage and current rated insulated banana sockets Banana sockets are coloured to indicate positive terminals in red negative terminals in black and current measurement connections in yellow A keyed heavy duty battery isolation switch would be provided on the interface to isolate the battery from the system Terminals for aMPPT load charging the battery would be available as banana sockets as would terminals for connection to a manual external load such as the RISE a c d c 1kW load bank Full wiring schematics for Wiring Enclosure
43. CURRENT 32A MAX CURRENT 32A RATED CURRENT 6 0A ACROSS 2 AutharsKieraniPeters Middle Wiring Level RATED DC VOLTAGE 125V POLES ONLY Date 12 03 2015 Wiring Diagram MODEL YLP60Wp 4 MODULES IN SERIES OPEN CIRCUIT VOLTAGE 22 0V SHORT CIRCUIT CURRENT 3 8A MODEL SEB 6445 NI X CATEGORY CAT III PERMISSABLE OPERATING TEMPERATURE 25 TO 80C PERMISSABLE OPERATING TEMPERATURE 40 TO 45C CHARACTERISTIC CURVE B 95 t APPENDIX K DOCUMENT WD3 1 6 ENCLOSURE A UPPER WIRING LEVEL WIRING DIAGRAM 19777777 di 2 2 2 2 2 2 2 5 5 5 5 5 5 5 5 E 6 80 7 82 52 a a A BPD Switch Ban Q 5 Qi Qa O Q x L 23 g Be Be Be 3 Telergonsrole
44. ENCLOSURE MIDDLE WIRING LEVEL WIRING DIAGRAM Enclosure A Load 20 30cm MPPT amp Battery 0 00 Internal connections for fault production PV MODULES TECH POLY MAX POWER 60W 8 MAX POWER VOLTAGE 17 5V MANUF YINGLI MAX POWER CURRENT 3 43A MODEL YLP60Wp 4 MODULES IN SERIES OPEN CIRCUIT VOLTAGE 22 0V SHORT CIRCUIT CURRENT 3 8A TEST SOCKETS TECH BANANA QTY 32 MANU SCHUTZINGER MODEL SEB 6445 NI X CATEGORY CAT Ill INSULATED YES POLYAMIDE MAX VOLTAGE 1000V MAX CURRENT 32A PERMISSABLE OPERATING TEMPERATURE 25C TO 80C DC ISOLATOR TELERGON ZFV32x2 MAX VOLTAGE 600V MAX CURRENT 32A PERMISSABLE OPERATING TEMPERATURE 40C TO 45C by connecting these terminals to the above module fault terminal points 2 2 2 2 2 2 2 BS 2 2 2 2 2 2 2 S 5 3 3 l3 8 418 3 13 3 13 5 12 3 13 5 4 3 I 2g 83 82 2 5 l o 1 8 o s 2 8 1 8 6 B o 2 8 gt 15 30cm 3 gt 2 S 23 a Telergon 8 Pole 8 8 5 313 6882 3 DC Isolator 8 3 5
45. Honours Thesis Project Report PV Array Troubleshooting and Educational Facility Kieran Peters Supervisors M Calais T Pryor S Glenister lt Murdoch UNIVERSITY This page is intentionally left blank I ACKNOWLEDGEMENTS I would like to express my appreciation to senior lecturers Dr Trevor Pryor and Dr Martina Calais technician Iafeta Jeff Laava and technical officer John Boulton for their guidance advice and technical support Thanks to their encouragement and experience throughout the past twelve months this project has become a successful reality This thesis would not have been possible without their support I wish you many years of trouble free teaching and working with this educational facility II ABSTRACT The Photovoltaic Array Troubleshooting and Educational Facility is a specialised experimentation platform for researchers and students to develop a greater practical understanding of photovoltaic modules arrays shading effects and fault scenarios The Facility was designed constructed tested and delivered to Murdoch University in order to complete the requirements of an undergraduate engineering honours thesis Proposed learning experiments involved the investigation of series parallel and bypass diode connections of or within photovoltaic modules partial shading and mismatch effects as well as the effectiveness of over current protection under different fault conditions in an extra low voltag
46. ID D D D D Enclosure B e o o o v o o o o v v v v v v v Flo amp amp lo Flo ja amp 5 s 4 5 Is s s 3 3 13 15 3 3 3 3 s 5 8 8 8 8 s s gla 8 lt 8 lt 8 8 M S o 8 0 8 2 8 gS 9 89 8 8 8 8 8 8 8 8 8 8 gt gt gt gt gt gt gt gt gt gt 2 gt gt gt PV MODULES TEST SOCKETS DC ISOLATOR DC BREAKERS m Murdoch DOCUMENT WD3 1 4 TECH POLY MAX POWER 60W TECH BANANA INSULATED YES POLYAMIDE MANU TELERGON ZFV32x2 MANU ABB POLES 2 UNIVERSITY 8 MAX POWER VOLTAGE 17 5V QTY 32 MAX VOLTAGE 1000V MAX VOLTAGE 600V MODEL 2CDS272001R0065 S202MB6 GANGED Enclosure A MANUF YINGLI MAX POWER CURRENT 3 43A MANU SCH TZINGER MAX CURRENT 32A MAX CURRENT 32A RATED CURRENT 6 0A ACROSS 2 Author Kieran Peters Lower Wiring Level MODEL YLP60Wp OPEN CIRCUIT VOLTAGE 22 0V MODEL SEB 6445 NI X PERMISSABLE OPERATING PERMISSABLE OPERATING RATED DC VOLTAGE 125V POLES ONLY Date 13 03 2015 Wiring Diagram 4 MODULES IN SERIES SHORT CIRCUIT CURRENT 3 8A CATEGORY CAT III TEMPERATURE 25C TO 80C TEMPERATURE 40C TO 45C CHARACTERISTIC CURVE B 94 APPENDIX J DocuMENT WD3 1 5 ENCLOSURE A MIDDLE WIRING LEVEL WIRING DIAGRAM
47. LOW Sch tzinger Part SEB 6445 NI GE 5 00 FEMALE BANANA SOCKET GREEN Sch tzinger Part SEB 6445 NI GN 10 00 FEMALE BANANA SOCKET BLUE Sch tzinger Part SEB 6445 NI BL 20 00 MALE BANANA PLUG BLACK Multi Contact Part 22 2260 21 22 1025 20 00 MALE BANANA PLUG RED Multi Contact Part 22 2260 22 22 1025 20 00 EQUIPMENT CABLE Taiyo Cabletec Part C3 RV 90 2 5SQBLACK20M 3 00 CURRENT SHUNT Murata Power Part 50A 50mV 3020 01096 0 8 00 SPST OUTDOOR SWITCH 8 00 200 6A CURVE B DC BREAKER ABB Part 2CDS272001R0065 S202MB6 8 00 PERFORATED 35 7 5 DIN RAIL Phoenix Contact Part 1207653 20 00 DIN RAIL END CAP Phoenix Contact Part 1206560 108 20 00 GROUND TERMINAL BLOCK Phoenix Contact Part 3044128 50 00 GREY TERMINAL BLOCK Phoenix Contact Part 3044364 50 00 BLUE TERMINAL BLOCK Phoenix Contact Part 3044500 20 00 GREY 4 CONTACT TERMINAL BLOCK Phoenix Contact Part 3048823 10 00 END COVER Phoenix Contact Part 3047028 5 00 2 WAY PLUG IN BRIDGE JUMPER Phoenix Contact Part 3030336 5 00 10 WAY PLUG IN BRIDGE JUMPER Phoenix Contact Part 3030271 5 00 8 00 MALE BANANA PLUG BLACK Multi Contact Part 22 2380 21 22 1203 8 00 MALE BANANA PLUG RED Multi Contact Part 22 2380 22 22 1203 60 00 MALE BAN
48. M LARGER IMAGE SHOWN IN APPENDIX 0 29 FIGURE 3 8 CONTROL PANEL B EXPERIMENT PLATFORM LARGER IMAGE SHOWN IN APPENDIX 29 FIGURE 3 9 EXAMPLE OF PARTIAL WIRING DIAGRAM FOR ENCLOSURE B FULL DIAGRAMS AVAILABLE IN APPENDIX Eich reete eae sea Er named ci ee A 31 FIGURE 4 1 PREPARED PV MODULE WITH BYPASS DIODES REMOVED AND THIRD CABLE ENTRY INSTALLED m 35 FIGURE 4 2 PHOTOVOLTAIC MODULE FLY LEADS INSTALLED WITH MC4 36 FIGURE 4 3 PV ARRAY MOCK UP ON INDUSTRY STANDARD MOUNTING 1 37 FIGURE 4 4 PV ARRAY MEASURED FOR ROTATION SHAFT CONSTRUCTION ALSO SHOWN IS ARRAY FRAME cesis dt cU EA C E C T 38 FIGURE 4 5 MODULE MOUNTING BRACKETS WITH EARTHING CONNECTION PINS 16 38 FIGURE 4 6 FACILITY FRAME CONSTRUCTED WITH PNEUMATIC CASTER WHEBEELS sese 39 FIGURE 4 7 ARRAY MOUNTED ON FACILITY FRAME USING PILLOW BLOCK 40 FIGURE 4 8 PV MODULE CABLE LOOM MEASURED AND CUT TO 5 7 41 FIGURE 4 9 ARRAY WIRING ROUTED THROUGH INDUSTRY STANDARD CONDUIT TO WIRING ENGEOSURES er deseen Scie dee eim ce ren dete 41 FIGURE 4 10 PV MODULE WIRING INTERFACE WITH ENCLOSURE A USING CUSTOM CABLE GLANDS 42 FIGURE 4 11 FACILITY TES
49. Modules Current Amps w 0 5 10 15 20 25 30 35 40 45 50 Voltage Volts Module A Combination Parallel Combination Figure 2 5 I V Current Voltage curves for mismatched PV modules Series and parallel combinations can be connected to form an array of photovoltaic modules Figure 2 5 shows a simple set of measurements taken using two PV modules on hand at Murdoch Figure 2 5 displays two combinations of modules that are not producing the same current are shown such a mismatch could occur due to a design error or more frequently due to partial shading on the under producing module Series combinations are shown to produce a much higher voltage than the individual modules and a parallel combination is shown to produce a high current while maintaining the same voltage as the single modules Similarly Figure 2 6 shows the resulting power produced by each combination It can be seen clearly that the photovoltaic module producing a lesser current limits the series combination power while the parallel combination remains free to generate as much power as possible given the limited current production 10 Power Output Comparison for Mismatched Modules 100 90 80 70 60 50 40 Power Watts 30 20 10 0 5 10 15 20 25 30 35 40 45 50 Voltage Volts m Module A 5 Combination a Parallel Combination Figure 2 6 P V Power
50. NT STRUCTURE AND RELATIONSHIP TO CHAPTERS nunsssesssenssessneesseenunsennnesnnnennn 3 FIGURE 2 1 A SIMPLIFIED SOLAR CELL SHOWING CREATION OF HOLE ELECTRON PAIRS 5 FIGURE 2 2 NEWLY MANUFACTURED MONOCRYSTALLINE PHOTOVOLTAIC CELLS 6 6 FIGURE 2 3 ONE DIODE MODEL EQUIVALENT CIRCUIT MODEL FOR A PHOTOVOLTAIC CELL 7 FIGURE 2 4 CROSS SECTION OF TYPICAL CRYSTALLINE LAMINATED PHOTOVOLTAIC MODULE 8 FIGURE 2 5 I V CURRENT VOLTAGE CURVES FOR MISMATCHED PV MODULES eere 10 FIGURE 2 6 POWER VOLTAGE CURVES FOR MISMATCHED PV MODULES eene 11 FIGURE 3 1 PROJECT DESIGN APPROACH 16 FIGURE 3 2 CONCEPT GOOGLE SKETCH UP DESIGN FOR FACILITY FRONT 19 FIGURE 3 3 CONCEPT GOOGLE SKETCH UP DESIGN FOR FACILITY REAR VIEW 19 FIGURE 3 4 TELOS STRUCTURE GUIDE FOR FEASIBILITY ANALYSIS nsnsessenssessseensseunnseunneunnsenunsennnesnnnenneen 21 FIGURE 3 5 DETAILED DESIGN FACILITY FRAME WITH TILTED ARRAY 12 27 FIGURE 3 6 EXAMPLE OF PARTIAL WIRING DIAGRAM FOR ENCLOSURE A FULL DIAGRAMS AVAILABLE IN APPENDIX 28 FIGURE 3 7 CONTROL PANEL EXPERIMENT PLATFOR
51. SABLE OPERATING u gt u 2 CATEGORY CAT III TEMPERATURE 25 TO 80C Enclosure A 5 3413 8 ajg o DC ISOLATOR MANU TELERGON ZFV32x2 MAX VOLTAGE 600V CURRENT 32A PERMISSABLE OPERATING TEMPERATURE 40C TO 45C Earth 40 50 Fault Switch DC BREAKERS DC Isolator 40 50 BLUE SEA SYSTEMS POLES 1 EACH MODEL 7050 7052 7053 PERMISSABLE RATED CURRENT 3A 5A 7A OPERATING Fault crtent shunt RATED DC VOLTAGE 32V DC TEMP 10C TO SUSSHITENESDUN gt CHARACTERISTIC THERMAL 60C ONLY MANU ABB POLES 2 MODEL 2CDS272001R0065 5202MB6 10 GANGED RATED CURRENT 6 0A 10 0A ACROSS 2 Alla RATED DC VOLTAGE 125V POLES ONLY leta ET CHARACTERISTIC CURVE rans ala Murdoch DOCUMENT WD3 2 4 Enclosure B Author Kieran Peters Lower Wiring Level Date 10 03 2015 Wiring Diagram Figure 3 9 Example of partial wiring diagram for Enclosure B Full diagrams available in APPENDIX L 31 3 3 Significant Design Issues One notable design issue encountered during the project was the mismatch between component data sheet specifications and real world specifications of the actual components Signifi
52. TING WITHOUT CONTROL 42 FIGURE 4 12 SENSOR MOUNTING PANEL 5 43 FIGURE 4 13 PV ARRAY WITH SENSOR PANEL GREY MOUNTED ON THE PLANE OF 44 FIGURE 4 14 ENCLOSURE A BACK PLATE WITH PARTIALLY COMPLETE WIRING ucts 45 FIGURE 4 15 WIRING ENCLOSURE BACK PLATE INSTALLATION AND 46 FIGURE 4 16 PAPER MOCK UP OF CONTROL PANEL GRAPHIC 47 FIGURE 4 17 INTERFACE WIRING FOR ENCLOSURE A CONTROL PANEL esee 48 FIGURE 4 18 COMPLETED FACILITY ON SITE AT MURDOCH ENGINEERING BUILDING 220 49 FIGURE 5 1 MAXIMUM POWER COMPARISON BETWEEN PV MODULES esent 51 FIGURE 5 2 MAXIMUM POWER VOLTAGE COMPARISON BETWEEN PV MODULES 52 FIGURE 5 3 MAXIMUM POWER CURRENT COMPARISON BETWEEN PV MODULES sisses 53 FIGURE 5 4 OPEN CIRCUIT VOLTAGE COMPARISON BETWEEN PV MODULES FIGURE 5 5 SHORT CIRCUIT CURRENT COMPARISON BETWEEN PV MODULES eere 56 FIGURE 5 6 FILL FACTOR COMPARISON BETWEEN PV MODULES seen tenente tenent
53. aid terminals to the MPPT Battery load shown in Error Reference source not found using banana plug leads 64 13 14 15 16 17 18 Move the Bypass Diode Switch to the ON I binary position Engage the system by turning the Master Isolator Switch to the ON position Measure the current flowing through the circuit as the module operates Note the solar radiation in the plane ofthe array and the module temperature and record the currents Disengage the system by turning the Master Isolator Switch to the OFF position Repeat steps 13 to 16 for any other measurement points of interest Shade part ofthe module with the supplied shading apparatus No more than 50 should be shaded This shaded section should be aligned with the left or right side ofthe photovoltaic module as per Figure 5 15 Figure 5 14 Unshaded photovoltaic module 23 Figure 5 15 Suggested partial shading pattern for photovoltaic module 24 19 20 21 22 Repeat steps 13 to 16 noting how the current bypasses part ofthe module through the bypass diodes Be sure to always disengage the system by turning the Master Isolator Switch before changing any current measurement connections Move the shade to different positions over the module while observingthe DMM display Take note of how the current flows change through the bypass diodes as the shade moves Move the Bypass Diode Switch to the OFF 0 binary position Repeat Steps 13 to 16 Disco
54. all comply with EN50521 be protected from contact with live parts in connected and disconnected states have suitable current ratings and be capable of accepting the cable used They shall require a deliberate force to separate have suitable temperature rating and be UV resistant and of a suitable IP rating if 80 exposed to the environment Install to minimise strain connectors only mate connectors ofthe same type from the same manufacturer Bypass diodes shall have a voltage rating at least 2xVoc mop a current rating of at least 1 4xIsc be installed so no live parts are exposed and protected from degradation due to environment factors AS5033 4 4 specifies several key installation and location requirements relevant to the Facility Overcurrent protection devices shall be located at the end of the cable that is electrically most remote from the photovoltaic array Disconnection means shall be provided to isolate the PV array from the PCE or application circuit and vice versa Suitably rated circuit breakers used for overcurrent protection may also provide load breaking disconnecting facilities AS5033 Table 4 3 shows disconnection device requirements in PV array installations AS5033 5 2 requires several warning labels and signs to be installed for several applications of photovoltaic modules Labels and signs shall be sufficiently durable for purpose in English visible when applicable and clearly legible AS5033
55. an extra low voltage d c installation may operate in one less conductor than the number of conductors in the circuit Isolators shall be clearly labelled such that any lay person could isolate the system ifthe need arose 84 APPENDIX C DETAILED PHOTOVOLTAIC MODULE SUN SIMULATOR RESULTS Module 1 Module 2 Module 3 Module 4 Module 5 Module 6 Module 7 Module 8 Module 9 Mod Type Yingli Yingli Yingli Yingli Yingli Yingli Yingli Yingli Yingli YL60Wp YL60Wp YL60Wp YL60Wp YL60Wp YL60Wp YL60Wp YL60Wp YL60Wp Date 2 03 2015 2 03 2015 2 03 2015 2 03 2015 2 03 2015 2 03 2015 2 03 2015 2 03 2015 2 03 2015 Time 14 47 08 14 45 02 14 29 44 14 26 43 14 32 35 14 35 30 14 37 53 14 40 17 14 43 00 Irradiance 100 01 100 007 99 9962 99 9874 100 018 100 008 100 051 100 019 99 9961 IrrCorr 100 100 100 100 100 100 100 100 100 Lamp Voltage 2050 2050 2050 2050 2050 2050 2050 2050 2050 Corrected To 100 100 100 100 100 100 100 100 100 Module 25 3871 24 7972 25 2877 23 811 23 8357 24 398 23 8265 23 8865 25 0968 Temp Corrected To 25 25 25 25 25 25 25 25 25 MCCC 0 9863 0 9863 0 9863 0 9863 0 9863 0 9863 0 9863 0 9863 0 9863 Voc 22 5782 22 6147 22 4414 22 3953 22 439 22 3026 22 4333 22 5683 22 5786 Isc 3 61904 3 51617 3 62285 3 63677 3 61983 3 63393 3 62223 3 62852 3 63367 Rseries 0 66161 0 63503 0 71214 0 70104 0 66841 0 63439 0 62817 0 68024 0 65414 Rshunt 712 168 1122 29 765 536 1091 33 454 7
56. at number of design choices would depend on component availability In the interest of brevity the most important parts researched are displayed in Table 1 below A full list of components used in the construction of the Facility are listed in APPENDIX 5 Table 1 Simplified component survey RS Australia Altronics Jaycar SolarMatrix These documents are essential for correctly Product Catalogues specifying real obtainable components throughout the Facility One of the largest issues encountered was an inability to access quality appropriate components that result in safe long running application in the real world Yingli Data Sheets Yingli Data Sheets were initially used wherever general physical or electrical dimensions associated with the PV modules are required These measurements shall always be cross checked against the actual modules when such an activity is possible 13 Lorentz Data Sheets See Yingli Data Sheets above It is notable that the Lorentz data sheets significantly deviated from the real Lorentz PV modules data sheets alone are not necessarily suitable as sole means of determining component suitability PROVA Curve Tracer UniT DMM and PROTEK DMM Manuals Measurement devices have limitations on the voltages and currents able to be safely measured These limitations impose design restrictions on the Facility IPD Telergon ABB and other d c Isolators Isolator
57. c cells are influenced by local conditions In general it was hoped that the Facility would prove to be operationally feasible and would fit in well with the Murdoch University teaching culture 3 1 4 5 SCHEDULE FEASIBILITY The schedule feasibility study was performed to determine if the project could be reasonably expected to be completed and ready for delivery within the allotted time frame Basic estimations for how long the system would take to develop were delivered to the client at week four of the project A reasonable schedule was developed using Gantt chart software tool Gantt Project This schedule is shown in APPENDIX E Deadlines shown in APPENDIX E were generally desirable instead of mandatory implying a certain degree of flexibility to accept short delays or setbacks was inherent in the project schedule It was determined that Murdoch University current technical feasibility level was sufficient meaning that further training or upskill activities would not be required This meant that given no extreme setbacks occurred the project schedule was feasible and the Facility would be completed on time 3 1 5 PRELIMINARY DESIGN During the preliminary design phase the overall system configuration was designed An array of eight photovoltaic modules would feed a control panel system housed in two enclosures Each enclosure would house a hard wired experiment terminal that prevents student access to voltages exceeding the projec
58. cantly the small form factor Lorentz 40W photovoltaic modules specified in the detailed design were ordered by a local supplier but upon arrival it was discovered that the manufacturer had deviated from the data sheet in several aspects most importantly the Lorentz modules that arrived were over sixty per cent longer than specified in the data sheet This additional length would not fit through the elevator doors or other required transit pathways without fairly exotic folding mounting mechanisms It was deemed preferable to instead select an alternative photovoltaic module that met the size and electrical requirements of the Facility The Yingli 60W square form factor module was then selected from a local retailer as the best available option Unfortunately such a decision had wide ranging impacts on the entire design since all cables switches sockets terminals protection devices and other component selections are dependent on the physical and electrical characteristics of the photovoltaic modules The result of a change to the photovoltaic module selection was a significant delay while an almost complete redesign ofthe system was accomplished at a stage where Facility construction should have been undertaken 3 4 Key Assumptions A number of assumptions concerning Facility use have been made during the design process These assumptions are necessary to avoid over designing the system in an attempt to produce a system that is functional safe
59. crepancies through severely mismatched modules should be avoided wherever possible Results from the sun simulation showed that no module performed at peak power at the manufacturer declared 17 50V d c with almost all modules exceeding 18V d c and two modules approaching an entire volt greater at maximum power than expected Repeat tests and later handheld IV curve tracer tests confirmed this finding and the discrepancy was assumed to be produced by either poor module binning during production or a low quality control environment 52 5 1 3 CURRENT AT MODULE MAXIMUM POWER The maximum power current is a measurement of the amount of charge flowing to the load when the photovoltaic module produces maximum power This parameter could be considered an important measurement for safe Facility operation as overcurrent protection devices may require certain magnitudes of current to operate For a number of potential fault current experiments the greatest magnitude currents available would be required so a comparison between module outputs would be useful for experiment design Results from the sun simulation Figure 5 3 determined that eight modules produced Imp currents of similar magnitude to the data sheet specifications but module two output was significantly lower The lower current module is the same that produced an unusually high voltage at maximum power while the output power is acceptable this module would limit the cu
60. d produce the control panel interface designs 3 1 1 RESEARCH Research formed an important early stage of system design for the Facility Research was required to determine the minimum legal and operational requirements for various system elements Research was undertaken to determine the minimum requirements of Australian Standards relevant to the Facility detailed in Section 0 to survey existing photovoltaic education teaching systems to familiarise project members with standard industry photovoltaic installation techniques and to determine the range of available components equipment and parts that may be used within the facility A search was conducted for published reports of similar systems This search was largely unfruitful with the exception of a Solar Trainer Laboratory at California Polytechnic State University and a Solar PV Troubleshooting Learning System manufactured by Amatrol in Indiana U S A The former focused on the mechanical tracking movement of a single photovoltaic module 10 and the latter on Balance of System Components such as power distribution grid connection and micro inverters 11 A small assortment of primary level 17 education resources for solar power learning were also discovered but found to be largely irrelevant due to the overly simplistic nature of concepts and models discussed in such works The Photovoltaic Array Troubleshooting and Educational Facility was therefore considered t
61. dard bypass diode location the junction box of each photovoltaic module would not only by impractical but also unsafe as the junction boxes house the terminals for each module meaning that a student would be able to easily connect more than five modules in series The bypass diodes would instead be housed in Wiring Enclosure A and controlled using switches on Control Panel A This configuration would require the addition of a third cable between the Wiring Enclosure A and each module to effectively provide the standard bypass diode connection point within the Enclosure Bypass cables would be installed with blue coloured insulation to differentiate them from the other array cables It should be noted that this configuration does not adhere to AS5033 4 3 as to do so would preventthe conduct of any experiments that feature the absence of bypass diodes Overcurrent protection devices were sized in accordance with AS5033 3 3 4 at a nominal current capacity of 6A Breakers were chosen due to the exceptionally large inherent cost of a fused student experimentation platform Control Panel A would receive fast breaking Curve B breakers for best protection while Control Panel B would require slower breaking Curve D breakers in order to actually observe any fault overcurrent flow for a period of more than a few seconds Isolators were chosen to be load breaking but shall be supported by the breakers as backup load breaking disconnection devices the breakers
62. diation Students would also be required to complete a supervised induction experiment before any unsupervised work could be performed using the Facility Such limitations should serve to safeguard students using the facility and provide them with the skills to manage these and other hazards fundamental to photovoltaic power generation 24 3 1 4 4 OPERATIONAL FEASIBILITY The operation feasibility study aimed to determine if the Facility would solve the problems defined in the project scope Desired operational outcomes included system reliability maintainability usability predictability and affordability Such an initial study relied mainly on performance metrics that could be considered extremely subjective student interaction with teaching tools vary from gentle careful touches to callously indifferent clobbering through to actual abuse and vandalism It was therefore determined to select components rated for heavy duty use in industry wherever possible and cross check designs with Murdoch University technical staff to leverage their considerable experience with system maintenance System predictability would be determined in part by the solar radiation and temperature conditions on each day of use but would exhibit an appropriately predictable response outside of these variables given adequate sensor instruments such variability would be used to enhance the Facility as a teaching tool for better student understanding of how photovoltai
63. dule can have significant impacts on the behaviour of the module or even the array of modules Best PV cell performance and return on investment therefore requires the smallest amount of shading possible 2 1 5 PHOTOVOLTAIC MODULE STRING ARRANGEMENTS Modules can be connected in a similar manner to simple voltage sources such as batteries Photovoltaic modules are however not easily modelled as ideal constant voltage or current sources and can be configured in series or parallel combinations to produce a range of output currents and voltages Series connected modules produce a voltage at maximum power approximately the sum of the individual modules maximum power voltages A string of series connected modules is limited by the module producing the lowest current at that voltage This module will dissipate the additional current generated by other modules in the string as heat Series combinations are typically used in industry to produce high array voltages in order to simplify converter design Modules connected in parallel theoretically produce a net current that is the sum of currents produced by each individual module in the string The voltage across each parallel PV module may be considered to be equal for the purposes of this simple working understanding The result of a parallel combination is to increase the total available current over a similar voltage range to the individual modules Current Output Comparison for Mismatched
64. e Low voltage Exceeding extra low voltage but not exceeding 1000 V a c or 1500 V d c 18 e Fault current A current resulting from an insulation failure or from the bridging of insulation 18 e Short circuit current A fault current resulting from a fault of negligible impedance between live conductors having a difference in potential under normal operating conditions 18 82 AS3000 1 5 3 specifies requirements for basic protection against direct contact fault protection against indirect contact Protection shall be provided against shock current arising from contact with parts that are live in normal service 18 Accessible conductive parts must not be live Protection against direct contact may be provided by basic protective provisions alone such as insulation barriers enclosures or obstacles Protection shall be provided against shock current arising from contact with parts that become live under fault conditions 18 Accessible parts must not become live in fault situations Protection against indirect contact may be provided by means of automatic disconnection devices and or insulation that would limit or prevent fault current to flow through a body Enclosures and insulation must be selected to appropriate an appropriate degree of protection against contact with direct or indirect currents and external influences AS3000 2 5 requires that active conductors shall be protected by one or more de
65. e B Breaker APPENDIX R DOCUMENT GD4 2 2 ENCLOSURE CONTROL PANEL GRAPHIC CUTTING INSTRUCTION DOCUMENT GD4 2 1 Murdoch Enclosure Author Kieran Peters Fault Current Experiment Graphic Date 14 05 2015 incl Student Access Points UNIVERSITY CONTROL PANEL B Battery Breaker 6ADCBreaker String AB Breaker String CD Breaker String EF Breaker String GH Breaker System DC Isolator 50A 50A 50mV 50mV 10 2596 10 2596 Fault Current Shunt e e Current Shunt z Manual Load MPPT Load Connection Connection Normally Closed 5A Breaker Normally Closed String AB Breaker MODULE B String CD Breaker String EF Breaker ee eee String GH 1 RR 4 50 pu o 10 2596 Battery Switch Current Shunt gt i 103 104 105 106 107 APPENDIX S LIST OF PARTS AND COMPONENTS USED WITHIN THE FACILITY Qty Description 15 00 FEMALE BANANA SOCKET BLACK Sch tzinger Part SEB 6445 NI SW 15 00 FEMALE BANANA SOCKET RED Sch tzinger Part SEB 6445 NI RT 26 00 FEMALE BANANA SOCKET YEL
66. e array The Facility provides for the safe measurement of voltages and currents of individual module or array sections of the interconnected array using handheld multimeters and portable IV curve tracers Research was conducted on background photovoltaic system theory module construction and array design followed by an in depth examination ofthe relevant legal regulations applicable to this project This research was followed by a basic feasibility analysis used to determine the practicability of this project as a means to satisfy the client requirements given the technical operational economic and scheduling opportunities available for application Once feasibility was demonstrated the Facility could be designed in detail using software tools with components specified sourced financed and ordered Upon arrival of the build components the Facility was constructed using industry standard tools and methods and tested for module performance and student level experiment suitability The Photovoltaic Array Troubleshooting and Educational Facility project was a complete success Many new experiments are now available to students particularly dealing with photovoltaic fault scenarios Almost all existing d c photovoltaic experiments from the Murdoch University Renewable Energy Engineering major can now be conducted in greater detail on a full array of modules while exposing students to industry standard components and techniques The Facility
67. e in Australia Standard document AS3008 of 2001 was also found to be a useful guide but is considered as a guide only as AS3008 deals with a c cables and wiring only The key elements of these documents essential to a full understanding of this project are outlined below general sections examined within each Standard shall be described as Standard ID Section ID For example Installation and safety requirements for photovoltaic PV arrays section 2 2 array mechanical designs would be describes as AS5033 2 2 2 1 7 AS5033 2014 INSTALLATION AND SAFETY REQUIREMENTS FOR PHOTOVOLTAIC PV ARRAYS AS5033 is a significant document used to ensure the Facility meets a number of legal requirements set by Australian Standards Methods for determining wire switch and fuse sizes and necessities are explored with the intention of protecting human life and Facility infrastructure Design configuration restrictions are specified for elements such as the frame array configuration cable routing enclosure design signage and so on A full analysis of the relevant AS5033 requirements is set out in APPENDIX A a reader not familiar with this Standard may find such an analysis useful for an understanding of the AS5033 requirements on the Facility 2 1 8 453000 2007 WIRING RULES AS3000 is an important document for the safety of people using and near to the Facility Colloquially known as the wiring bible thi
68. ed to interrupt the full prospective currents 55033 4 3 specifies that no disconnecting device shall have exposed live parts in connected or disconnected state Such devices shall be selected for appropriate current ratings for the expected temperatures and greater equal to the overcurrent protection devices to which they are attached Switch disconnectors shall not be polarity sensitive rated to interrupt the full load and prospective fault currents interrupt all conductors simultaneously and be capable of being secured in the open position ELV plug connections for interruption under load may be used instead if the equivalent level of safety and performance can be assured Cable sizing shall be determined with regard to overcurrent protection ratings where in use the maximum normal operating current and the voltage drop and prospective fault current choose largest size of these Derating factors specified by manufacturer may apply particularly given the expected elevated operational temperatures of the system Cable types shall have suitable temperature rating and if exposed to the environment be UV resistant or protected from UV light be flexible multi stranded Cables shall be supported such that they do not suffer fatigue and are protected from abrasion tension compression and cutting forces see AS3000 Plastic cable ties shall not be used as a primary means of support AS5033 4 3 requires that plugs sockets and connectors sh
69. er solar radiation passes through 1 5 thicknesses of the Earth s atmosphere This filtered spectrum corresponds to noon on a clear sunny day when the sun is about sixty degrees above the horizon and the photovoltaic module directly faces the sun 19 This machine is suitable for use in research and development applications as well as high volume automated production systems 20 The primary objective of these tests was to determine the existence of any faults or issues with the modules match similar modules into groups and enhance the value of the Facility as a teaching tool by providing detailed module characteristics in a Facility Data Sheet for future use Murdoch University staff may design future teaching activities that could rely on such measured characteristics The sun simulator outputs a characteristic IV curve as well as various key parameters such as series and shunt resistance maximum power point fill factor open circuit voltage and short circuit current A summary of key sun simulator results is shown in Table 4 and shall be explored in the following pages Table 4 SPI SUN Simulator Results for PV Modules Data Parameter 1 2 3 4 5 6 7 8 9 Unit Sheet 60 3 62 15 60 80 60 75 61 39 61 25 61 11 61 17 61 73 62 52 Vpm 17 50 18 21 18 40 17 97 18 07 18 08 17 99 18 14 18 14 18 40 Ipm 3 43 341 330 338 3 40 339 3 40 337 340 340 Voc 22 0 22 58 22 61 22 44 22 40 22 44 22 30 22 43 22 57
70. es resistance Rs may be used to represent the resistance of the silicon wafer the metal contacts and the resistance between silicon and metal contacts to current flow A shunt resistance represents manufacturing defects that lead to internal current flow Typically non ideal junction properties or impurities will give rise to this behaviour For the purposes of this document the shunt resistance can be considered a constant A perfect PV cell would have zero or very low series resistance and an infinite or very high shunt resistance A diode permits current to short circuit across the cell in shunt configuration under certain conditions q V IRs Ip Ig lm 1 where q is element charge and is the Boltzmann constant Using Kirchoff s current law to solve for the current through the load loan Ip lioAp Rioap Figure 2 3 One diode model equivalent circuit model for a photovoltaic cell 2 1 3 TYPICAL CRYSTALLINE PHOTOVOLTAIC MODULE COMPONENTS Typical crystalline photovoltaic modules consist of a combination of individual photovoltaic cells encased in a protective structure that permits photons to enter the cells while preventing damage from torsion weather vandalism physical impacts etc A generic cross section of such a module is shown in Figure 2 4 An aluminium frame is often but not always used to provide the module with rigidity and simplify mounting options interconnector solar cell EVA
71. f photovoltaic modules with a range of measurement and testing capacities available to students Proposed learning experiments involve the investigation of series parallel and bypass diode connections of within PV modules partial shading and mismatch effects as well as the effectiveness of over current protection under different fault conditions in an extra low voltage PV array The facility would need to allow for the safe measurement of voltages and currents of individual module array sections of the interconnected array at least three strings in parallel using handheld multimeters and portable IV curve tracers The purpose of this thesis project is to fulfil this need through the design construction and delivery of such a teaching tool The Photovoltaic Array Troubleshooting and Educational Facility project was a complete success The project came in on time under budget even after a number of setbacks A wide range of project management technical legal financial and research skills outside the requirements of many honours thesis projects were developed throughout the course of the project to the exceptional benefit of both Mr Kieran Peters and Murdoch University Many new experiments are now available to students particularly dealing with photovoltaic fault scenarios This is a crucial area of photovoltaic system design that was previously available only as theoretical models or limited demonstrations Almost all existing d c photovoltaic
72. he diagram in APPENDIX P and permits safe measurement ofhigh currents by inferring current using Ohm s law Bridge the red banana sockets atthe top end of each String on the Control Panel using banana plug leads This step connects all four strings in parallel to form the array circuit shown in Figure 5 17 Connect the array positive and negative terminals to the MPPT Battery load shown in Error Reference source not found using banana plug leads Ensure the Fault Isolator Switch provided external to the Wiring Enclosure B is in the OFF binary position Engage the battery by inserting the key and turning the Battery Switch to the ON position Engage the system by turning the Master Isolator Switch to the ON position Measure the current flowing through the circuit as the modules operate Note the currents produced by each string Disengage the system by turning the Master Isolator Switch to the OFF position Engage the Fault Isolator Switch by turning the dial to the ON I binary position Engage the system by turning the Master Isolator Switch to the ON position Measure the current flowing through the circuit as the modules operate Note the currents produced by each string How has this changed from Step 8 Ifthe string overcurrent protection actuates disengage the system using the Master Isolator Switch wait one minute and then repeat the experiment Disengage the system by turning the Master Isolator Switch to the OFF positi
73. hic incl Student Access Points 100 APPENDIX DOCUMENT GD4 2 1 ENCLOSURE CONTROL PANEL GRAPHIC Murdoch WW UNIVERSITY CONTROL PANEL B DOCUMENT 604 2 1 Author Kieran Peters Date 14 05 2015 Enclosure Fault Current Experiment Graphic incl Student Access Points Battery Breaker 6A DC Breaker String AB Breaker String CD Breaker String EF Breaker String GH Breaker System DC Isolator String AB Breaker MODULE B String CD Breaker String EF Breaker 50A 50mV 0 25 Current Shunt 9 x o i a x o o 50 50mV 10 2596 86 50A 50mV 10 2596 Fault Current Shunt Current Shunt Manual Load MPPT Load Connection Connection 50 Normally Closed 20 5A DC Normally Closed Battery Switch 2 i 101 APPENDIX DOCUMENT GD4 1 2 ENCLOSURE CONTROL PANEL GRAPHIC CUTTING INSTRUCTION Murdoch is W UNIVERSITY CONTROL PANEL A lo Module D Bre System DC Isolator Connec tion Battery Switch Breaker Modul
74. his particular module produces much less current from Isc to Imp under the same sun simulator tests as the other units this IV characteristic behaviour is shown in Figure 5 10 As fault current detection and overcurrent protection device actuation form an important subset of experiments available on the Facility an emphasis must be placed on maximum string current production Therefore as the photovoltaic module that produces the least current under most circumstances module two was selected to serve as the spare unit for the Facility 61 Module 2 Current Amps Power Watts Voltage Volts Figure 5 10 IV and PV plots for PV Module 02 5 3 Practical Experiment Results A number of sample practical experiments were developed to enhance the effectiveness of the Facility as a teaching tool Experiments placed an emphasis on series and parallel module connections in shaded and unshaded situations bypass module connections and operation array string behaviour under normal and fault scenarios and supervised overcurrent protection device actuation Experiments developed were generally short discrete and intended for expansion by Murdoch University teaching staff before release to students To demonstrate the effectiveness of the Facility as an experiment platform two experiments were selected for further testing and verification 5 3 1 SAMPLE EXPERIMENT 01 BYPASS CURRENT OBSERVATION 5 3 1 1 OBJECTIVES The objective
75. ion C ed Spire Solar 2012 R J Komp Practical Photovoltaics Plant Energy Manage United States vol 6 1982 C Honsberg and S Bowden PVEducation org Retrieved October vol 10 p 2012 2010 G Broun KP Thesis Top Down PV Module Diagram ed 2014 G Broun KP Thesis Top Down PV Module with Shading Diagram ed 2014 All diagrams artwork and charts were generated by the author or reproduced with permission of the content owners or copyright holders 76 APPENDICES APPENDIX A AS5033 2014 REQUIREMENTS ANALYSIS AS5033 is a key document for ensuring the Facility meets Australian Standards Methods for determining wire switch and fuse sizes and necessities are explored with the intention of protecting human life and Facility infrastructure AS5033 2 1 3 describes several basic photovoltaic array configurations and illustrates the general functional configuration powered system AS5033 2 1 6 sets out requirements for series parallel configurations of modules Most notably PV strings connected in parallel shall have matched open circuit voltages within 5 per string to avoid circulating currents an important but reasonably non intuitive safety aspect and modules that are electrically in the same string shall be all in the same orientation within 5 azimuth and tilt angle AS5033 2 1 7 specifies that batteries connected to photovoltaic systems shall have fault curren
76. is also available for open days and promotions and shall be used to attract new students to the industry the school and generate a greater enthusiasm for solar power generation LIST OF CONTENTS I ACKNOWLEDGEMENTS ABSTRACT LIST OF CONTENTS IV LIST OF FIGURES V LIST OF TABLES VI LIST OF SYMBOLS VII LIST OF ABBREVIATIONS CHAPTER 01 INTRODUCTION 1 1 Project Introduction 1 2 Document Structure CHAPTER 02 RESEARCH AND LITERATURE REVIEW 2 1 Photovoltaic Module Research 2 1 1 The Photovoltaic Effect 2 1 2 The One Diode Model Applied To Crystalline Photovoltaic Cells 2 1 3 Typical Crystalline Photovoltaic Module Components 2 1 4 Shading Effects On Crystalline Photovoltaic Modules 2 1 5 Photovoltaic Module String Arrangements 2 1 6 Bypass Diodes Photovoltaic System Regulations Research 2 1 7 AS5033 2014 Installation and Safety requirements for photovoltaic PV arrays 2 1 8 AS3000 2007 Wiring Rules 2 1 9 AS3008 1 2010 Electrical Installations Selection of cables 2 2 Available Products and Components 2 3 Existing Projects and Systems ON 12 12 12 13 13 15 CHAPTER 03 DESIGN METHODOLOGY 3 1 Design Approach 3 1 1 Research 3 1 2 Conceptualisation 3 1 3 Design Requirement Analysis 3 1 4 Feasibility Analysis 3 1 5 Preliminary Design 3 2 Detailed Design 3 3 Significant Design Issues 3 4 Key Assumptions CHAPTER 0
77. itive and negative terminals of one module to the Control Panel Manual Load Connection using banana plug leads Manual Load MPPT Load Connection Connection Figure 5 12 Manual Load Connection control panel Figure 5 13 MPPT Load Connection control panel layout layout 3 Ensure the all module circuit model switches shown as white circles in Figure 5 11 are in the ON I binary position and all breakers are in the ON position 4 Engage the system by turning the Master Isolator Switch to the ON position Note the module temperature and solar radiation in the plane ofthe array 6 Trace an IV curve for the module using the PROVA unit Save this curve and note the time ID 7 Move the three vertically oriented module circuit model switches to the OFF binary position Repeat Steps 4 through 6 8 Disengage the system by turning the Master Isolator Switch to the OFF position Configure up to three modules in series parallel or some combination of series and parallel using banana plug leads 10 Repeat Steps 3 through 8 for your chosen combination Part B 11 Connect UniT DMMs as ammeters inline between various points on the module circuit diagram by bridging the yellow connection banana sockets in Figure 5 11 with banana leads These DMMs shall display the current movement around the circuit 12 Disconnect the module positive and negative terminals from the Manual Load Connection and instead connect s
78. l Facility is specialised experimentation platform for researchers and students to develop a greater understanding of photovoltaic modules arrays shading effects and fault scenarios The Facility was designed constructed and tested to complete the requirements of an undergraduate engineering honours thesis Figure 1 1 Photograph of Facility and Control Panel A as pictured in the PV in Australia Report 2014 1 For several years Murdoch University has operated a number of courses involving photovoltaic system design particularly in the field of Renewable Energy Engineering These courses involve practical experiments in addition to software and mathematical simulations Academic chairs course supervisors identified broad range of photovoltaic experiments considered appropriate as learning exercises for future students Proposed learning experiments involve the investigation of series parallel and bypass diode connections of within PV modules partial shading and mismatch effects as well as the effectiveness of over current protection under different fault conditions in an extra low voltage PV array The facility should allow for the safe measurement of voltages and currents of individual module array sections of the interconnected array at least three strings in parallel using handheld multimeters and portable IV curve tracers 2 Fault finding involves conducting tests on electrical installations to di
79. lation for example when configuring protection systems or meeting regulation requirements As discussed in Chapter 02 AS5033 2 1 6 limits the variance between module Voc values within each string and between strings to limit the potential for circulating currents within the array The module open circuit voltage was an important consideration for the Facility as this parameter provided a reasonable expectation of the maximum voltage magnitude output available to students With this information in hand design of the protection systems string configurations and decisions on the quantity of individual modules provided for student configuration could be produced 54 22 65 22 60 22 55 22 50 22 45 22 40 22 35 22 30 22 25 22 20 22 15 22 10 1 2 3 4 5 6 7 8 9 PV Module Identification Number Voltage at Open Circuit V Figure 5 4 Open circuit voltage comparison between PV modules Figure 5 4 shows a comparison ofthe module Voc measurements As with the module voltage at maximum power the open circuit module voltage was generally greater than specified on the manufacturer data sheet This parameter varied by as much as 1 39 between modules this difference was not considered to be of great concern as the Facility array strings for Enclosure B would be made of two modules in series meaning that even were the modules with the largest discrepancy placed in series the facility would still comply with AS5033 2 1 6
80. ll points in the component acquisition phase emphasis was placed on obtaining real world industry standard parts for maximum practical student experience In general component selection and acquisition was dictated by part availability particularly given the time constraints imposed by complications during the design phase 4 2 System Construction 4 2 1 PV MODULE PREPARATION Photovoltaic modules were prepared for installation on the Facility by removing the pre installed bypass diodes cutting a third cable entry point in module junction boxes installing short fly lead cables with connectors and finally testing the performance characteristics of each module Photovoltaic module junction boxes were opened to reveal bypass diode connection points Yingli Solar solders bypass diodes in place inside a low form factor junction box These bypass diodes were carefully de soldered from the module to prevent automatic bypass diode operation Figure 4 1 bypass diodes were later installed inside Wiring Enclosure A with a control mechanism to facilitate a bypass of current around cells when desirable 34 Bypass diodes removed from junction box lt STOP x Additional MC 4 connection cable gland Figure 4 1 Prepared PV Module with bypass diodes removed and third cable entry installed The low form factor junction boxes were modified using a cutting tool to accept a third cable enabling an external bypass diode con
81. ltage Voc Short Circuit Current Isc MPP Voltage MPP Current Maximum Panels in Series 4 Parallel Pairs Max Available Voltage to Student Max Available Current to Student Max Voltage Per Terminal Output Max Current Per Terminal Output Fuses 1 5 x Isc lt 3 615 lt Minimum String Fuse Size Maximum String Fuse Size 4 Parallel Pairs Typical Available Voltage to Student Typical Available Current to Student Typical Voltage Per Terminal Output Typical Current Per Terminal Output Appendix Figure 6 5 Sunpower 40W module suitability selection matrix Sunpower SW40 40 0 W Polycrystalline 10 DOWN 21 5 y 2 4 17 9 V 2 2A 5 Modules 92 Panel Length Panel Width Fittings Length Proposed Array Width Proposed Array Length Angle Angle Array Width x Array Height y Min Pivot Height Angle Angle Array Width x Array Height y Min Pivot Height Angle Angle Array Width x Array Height y Min Pivot Height 540 mm 660 mm 160 mm 1780 mm 1980 mm 5 degrees 0 08727 radians 1773 mm 155 mm 78 mm 55 degrees 0 95993 radians 1021 mm 1458 mm 729 mm 65 degrees 1 13446 radians 752 mm 1613 mm 807 mm Product Identification Peak Power Technology Manuf Tolerance Open Circuit Voltage Voc Short Circuit Current Isc MPP Voltage MPP Current Maximum Panels in Series 4 Parallel Pairs Max Available Voltage to Student Max Available Curre
82. mage from over enthusiastic student interaction After a tour of the printing facilities of the local supplier ImageSource a large format printing machine was selected to transfer the graphic design to the Opal backings Figure 4 16 shows a paper mock up of each control panel by the printer and was used to resolve several minor issues with printing and cutting A fine resolution CNC style machine was chosen to cut holes for each ofthe banana sockets and the breakers 46 Figure 4 16 Paper mock up of control panel graphic design Once the control panels were printed and holes cut delivery was taken and further construction continued on site at Murdoch University Approximately one hundred banana socket terminals were installed through the Opal backings along with small breakers and keyed switches for battery control These interface elements were wired together appropriately to permit student access to experiment measurement points in a logical fashion seen in Figure 4 17 Emphasis was placed on ensuring the control panels will last for the life of the system As a result of this the control panel construction phase took a reasonably long time but this was preferable to a rushed job given that student safety not to mention AS3000 1 6 compliance would depend on the ability of these control panels to prevent student access to dangerous voltages or currents within the Facility 47 Figure 4 17 Interface wiring for Enclosure A control
83. nce a limited reverse voltage and the IV curve changes shape to reflect this It was observed that currents flow through bypass diode pathways on the Control Panel A graphics as currents actually bypassed the shaded cells to the middle of the string of cells within the module the bypass current flowed through the left hand diode when the right hand cells of the module were shaded the right hand diode when the left hand cells were shaded and through both diodes to bypass the module completely when the shading was great enough across the whole module The diodes are shown to reduce the effect of the shaded cell on the Facility output particularly at lower voltages Many such configurations are available for student experimentation and will serve as a hands on learning platform for understanding these reasonably non intuitive electricity generation behaviours 66 Three Parallel Modules One Partially Shaded 9 90 8 80 7 70 6 60 lt 50 54 40 8 o a 3 30 2 20 1 10 0 0 0 5 10 15 20 25 Voltage V 1 WITH BPD WITHOUT BPD P W WITH BPD e P W WITHOUT BPD Figure 5 16 Sample Experiment 01 IV and PV curve result for three parallel modules 5 3 2 SAMPLE EXPERIMENT 02 STRING FAULT ANALYSIS 5 3 2 1 OBJECTIVES The objective of Sample Experiment 02 was to explore the location and effect of a short circuit fault in one string on the current production of the photovoltaic module array
84. nderneath that served to secure each run of modules together in a custom array frame and mount the array on the Facility 36 Figure 4 3 Array mock up on industry standard mounting rails The best array tilt angle to maximise the potential use of incoming solar radiation changes according to solar geometry and location of use Because maximum current production would be required for certain fault scenario experiments using the facility a basic method of altering the array angle would be required To facilitate tilt angle adjustments a shaft was fabricated upon which the array would rotate about a horizontal axis This shaft is shown in Figure 4 4 whilst measurements for fixing arrangements were made The shaft was fixed to the array frame using the ten millimetre channels of each Schletter rail and is held by pillow block bearings on the main Facility frame to permit smooth rotation Array rotation is permitted between approximately sixty five degrees from horizontal to nine degrees from horizontal with angles outside this range prohibited by automatic micro switch control of the array tilt motor and backup rubber stoppers Array rotation is driven by a modified winch motor through a reduction gearbox capable of producing enough torque to hold the array steady at a chosen angle Modules were secured to frame rails using Schletter earthing PV mounts These mounts shown in Figure 4 5 pierce the frame of each photovoltaic module when
85. nection A third cable gland hole was cut into each module junction box to accept a custom cable addition to each module that carries bypass currents through the system A combination MC4 connector cable gland visible in Figure 4 1 and Figure 4 2 was used to minimise the cost and labour required for each module MC4 connectors are the current industry standard string connector for photovoltaic systems and were used for all main photovoltaic module cables to assist in the exposure of students to as much real world equipment as practicable MC4 specific crimping tools were prohibitively expensive at the time of construction so cables were terminated with MC4 pins by hand crimping connectors with pliers and soldering to ensure connections would last for the life of the system Once fly lead cables were installed each module was tested as per Chapter 05 35 Figure 4 2 Photovoltaic module fly leads installed with MC4 connectors 4 2 2 PHOTOVOLTAIC ARRAY FRAME CONSTRUCTION The photovoltaic modules were mounted on industry standard mounting rails manufactured by Schletter Mounting rails serve the purpose of supporting and fixing the modules in place A mock up of the array for measurement on these rails is shown in Figure 4 3 minor frame modifications were required as the Yingli photovoltaic modules were slightly wider than specified by manufacturer data sheets The rails used were a typical roof mount style with a ten millimetre channel u
86. neering amp Energy Building s North East Roof Engineering Murdoch University Kempin s thesis involved the production of a PV educational training facility albeit on a larger scale than this project This document has proved valuable for insight into the challenges faced when constructing PV training facilities Thesis Project Benjamin Marshall o Marshall Ben 2012 Solar Glider Marshall s thesis involved the design and construction of a small photovoltaic powered model aircraft This document was useful as a guide to technical representations of reasonably difficult concepts e Solar Trainer for laboratory systems education Dolan Dale S Lisa Friedman Jonathan Huff and Taufik Taufik Solar trainer for laboratory photovoltaic systems education 2012 o As with Kempin s thesis this document has provided a valuable insight into the production of training and laboratory equipment for use by students 15 CHAPTER 03 DESIGN METHODOLOGY 3 1 Design Approach A typical engineering design approach was observed throughout this project Figure 3 1 shows the design approach as a flowchart where each stage is completed sequentially until the design is finalised Research Australian Standards design installer references Product catalogues and component data sheets Design requirement analysis Requirement conflicts removed e Client expectations noted e Usage transit sites examined
87. nnect the DMMs and load and return the system to the standard configuration 65 23 Plot IV curves for the module in excel How does engaging the bypass diodes change the shape of these curves 24 Annotate circuit diagrams to show how the current flows when the module is shaded Which bypass diode protects each side of the module What happens when there are no bypass diodes connected 5 3 1 5 RESULTS CONCLUSIONS Despite the winter weather conditions at the time of conducting this experiment the Facility performed well In fact the low ambient temperatures on the day contributed to a greater than rated module output for the measured incoming solar radiation A number of module combinations in series and parallel were conducted In the interest of brevity one of the many potential combinations of modules is shown in Figure 5 16 below This combination required the connection of three modules in parallel such a configuration is unusual within industry but serves here to demonstrate the behaviour of parallel connected strings in a safe low voltage situation It can be seen in Figure 5 16 that a module fitted with bypass diodes is able to produce greater magnitude current than a module without bypass Without the bypass diode the combined IV curve is limited to the ISC of the shaded cells and a large amount of power is dissipated in these shaded cells With bypass diodes engaged on the shaded module the shaded cells experie
88. nt to Student Max Voltage Per Terminal Output Max Current Per Terminal Output Fuses 1 5 Isc lt 3 375 lt Minimum String Fuse Size Maximum String Fuse Size 4 Parallel Pairs Typical Available Voltage to Student Typical Available Current to Student Typical Voltage Per Terminal Output Typical Current Per Terminal Output Appendix Figure 6 6 Yingli 40W module suitability selection matrix Polycrystalline 3 DOWN 2 3 17 5 V 2 3 5 Modules 2 4xlsc 5 4 A 4A 6A 93 APPENDIX DOCUMENT WD3 1 4 ENCLOSURE A LOWER WIRING LEVEL WIRING DIAGRAM Srl sy 0 2 2 2 E 2 2 E 5 32 32 a a 3 7 gt gt BPD Switch Bank Qo A as ta L 3 223 3 23 23 23 Telergonspole amp 5 amp 5 26 5 amp 5 amp 5 DC Isolator 5 BIB D D D D D D D D D D D
89. o be reasonably unique because it caters to an altogether different area of essential photovoltaic system design understanding outlined in the introduction of this document A survey was conducted of available photovoltaic modules components and equipment It was found that the majority of the locally available modules were supplied with poor documentation anumber of modules simply did not match the physical or electrical dimensions of their respective datasheets Many components ideal for use in the Facility were available with a short delay so time was allotted in the project schedule to account for such delays In general whatever components not available from local suppliers could be ordered from national or international suppliers as required with an additional shipping charge applied 3 1 2 CONCEPTUALISATION Facility conceptualisation occurred with the aid of a number of elements including personal experiences with current relevant engineering experiments meetings and discussions with relevant Murdoch University staff for ideas concepts and warnings An examination of appropriate locations for facility use assisted in the generation of ideas for system design Conceptual drawings were produced using tactile pen and paper whiteboard and software methods such as Google Sketch Up shown in Figure 3 2 and Figure 3 3 This stage represents a significant creative design phase in the project where a reasonably unstructured process
90. occurred 18 NARAN WR AANA DON SANS N NW LARADA Figure 3 2 Concept Google Sketch Up design for Facility front view VAN Vy NANA AAAS 525255555 ANN NWN NY RER VANISSA RN FSIS TS 7 TIS SIS FIT 77 7 Figure 3 3 Concept Google Sketch Up design for Facility rear view 19 3 1 3 DESIGN REQUIREMENT ANALYSIS The design requirement analysis focused on understanding the specific scope of the project the operation of the Facility to be produced and the additional occasionally conflicting requirements of several members of Murdoch University staff Conflicts occurred between directives of individual project supervisor staff members as well as between said directives and the relevant Australian Standards Key expectations were noted including requirements for current and voltage for certain experiments Facility usage locations and subsequent transit pathways and methods After several rounds of short discussions and informal interviews all design requirement conflicts were removed and the resulting requirements consolidated to a single Scope Sites for facility situation were then examined along with all required doorways corners corridors and elevators to reach these locations Proximity of pr
91. of Sample Experiment 01 was to explore the effect of partial shading on photovoltaic module IV curves installed in various series and parallel configurations Bypass diodes shall be examined as a solution to poor performance characteristics with focus on improving the electrical power production of crystalline modules under said shading Upon 62 completion of Sample Experiment 01 student would have developed a greater understanding of shading effects on crystalline technology modules bypass solutions and IV curve tracing Module A Breaker Figure 5 11 Facility control panel section required for Sample Experiment 01 5 3 1 2 EQUIPMENT REQUIRED Facility Wiring Enclosure A shown in APPENDIX PROVA 210 Solar Module Analyzer IV Curve Tracer with custom banana leads e Temperature Sensor or digital thermometer 5 DMMS 240V DMMs used e Handheld DMM wired to Irradiance Sensor on Facility e Shading device 5 3 1 3 SAFETY REQUIREMENTS The experiment involved electrical connections with voltages up to 91V d c and currents up to 15 A Although arcing is unlikely in this experiment great care should be taken that all electrical connections are checked for tightness Covered sturdy shoes and sun protection shall be required 5 3 1 4 METHOD Part A 1 Connect PROVA unit to the positive and negative external load terminals of the Enclosure A Control Panel the Control Panel 63 2 Connectthe pos
92. of light delivered through grid of metal that forms one electrical contact of the cell The other region is doped with different impurities that have less than four outer electrons additional electrons are required for a complete bind into the crystal structure but these can be borrowed from nearby atoms producing a shift in the placement of the missing electron These positive charge holes outnumber the free electrons in the region so the region is described as a p region 4 The p type and n type semiconductors are brought together to form a metallurgical junction A metallic layer on the back of the cell serves as the other electrical contact for the diode When photons enter the cell through the front a current will flow through an external path connecting the two metallic contacts 5 Other contact configurations exist but this simple model is sufficient for the purposes of understanding this document Figure 2 2 Newly manufactured monocrystalline photovoltaic cells 6 2 1 2 THE ONE DIODE MODEL APPLIED TO CRYSTALLINE PHOTOVOLTAIC CELLS The behaviour of a photovoltaic cell may be represented as an equivalent electrical circuit model Such models are developed primarily for one semiconductor cell and assume that all connected cells are identical but are sufficient for this analysis Current produced as photons excite electrons in the semiconductor is represented by a current source producing current I A seri
93. on Repeat Steps 10 through 13 using various Manual Loads in series with the MPPT Load if available Disconnect the DMMs and load and return the system to the standard configuration Compare the current flows for each string and the load in excel How does the fault change these currents Will the overcurrent protection devices actuate with a large load connected to the array 70 5 3 2 5 RESULTS CONCLUSIONS The Facility performed well and the hidden fault exhibited an expected behaviour and served well to highlight the limitations of overcurrent protection as a protective device in photovoltaic arrays The Facility operator was able to find the location and nature of a fault on the array Figure 5 19 shows that in the blue no load scenario strings CD EF and GH operate in a business as usual fashion to feed in to the faulty string backwards through Module A this observation points to a short somewhere on string AB to ground After a short time the String AB Breaker actuated and shut down the faulty string protecting the system and any bystanders as per AS5033 9 String Current Measurements 15 10 5 10 15 Current Amps String AB String CD String EF String GH To Load Array Section Measured No Load Situation E Light Load Situation Heavy Load Situation Figure 5 19 String current measurements for Sample Experiment 02 under various loads Under the light load red scenario the three normally opera
94. ontrol panels a battery storage box and a sensor mounting panel in the plane of the array The sensor panel shown in Figure 4 12 and Figure 4 13 shall permit simple measurements of incoming beam direct solar radiation in the plane of the array an important parameter for many photovoltaic system calculations This panel was constructed of a ten millimetre thick heat resistant rigid polyvinyl chloride panel with an aluminium frame to mimic the surrounding photovoltaic modules and installed in the centre of the array Figure 4 12 Sensor mounting panel construction 43 Figure 4 13 PV Array with sensor panel grey mounted on the plane of array 4 2 5 WIRING ENCLOSURE ASSEMBLY Facility wiring enclosures were carefully planned to provide detailed designs in Section 3 2 Using these detailed designs shown in APPENDIX I through APPENDIX N the enclosure back plates were drilled to accept DIN rail terminal mounts and cable trays Wiring was routed between rails of terminals to form the required electrical circuits DIN rails were installed as per 52756 with all rails parallel to the primary photovoltaic module terminal connections 17 Cable trays installed throughout each back plate serve to hide cables that cannot be routed cleanly from view 44 ejs eie etre SEE Figure 4 14 Enclosure A back plate with partially complete wiring Murdoch University policy is to display high s
95. oposed usage sites to mains power outlets was examined and found to be acceptable Annual average peak sun hours and incoming beam radiation data from local sites were examined to ensure adequate sunlight would be available during all Murdoch University teaching periods With the additional aid Solar Pathfinder solar siting device the required siting locations were determined to be suitable for use year round The main intended usage site of Engineering Building 220 on the South St Murdoch University campus 3 1 4 FEASIBILITY ANALYSIS A basic feasibility analysis was performed to ensure the project was feasible under the current design requirement understanding The TELOS structure Technical Economic Legal Operational and Scheduling was used as a guide to direct this analysis 20 Technical Feasibility Economic Feasibility Legal Feasibility Operational Feasibility Schedule Feasibility Figure 3 4 TELOS structure guide for feasibility analysis 3 1 4 1 TECHNICAL FEASIBILITY The technical feasibility study attempted to determine whether Murdoch University has the necessary technical expertise to handle completion of the project It was necessary to gain an understanding of the present technical resources of Murdoch and their applicability to the expected needs of the proposed Facility A simple evaluation of the skills tools Hardware and software available and how these meet the needs of this project s produc
96. ovoltaic modules was chosen for the array as shown in Figure 3 5 To fit through the elevator and external doorways the array would tilt ona horizontal shaft to a larger angle from horizontal than required for maximum beam solar radiation Given these restrictions the Facility frame was constructed as a pair of A frames on a rectangular supporting structure the maximum width and length permitted Frame materials were chosen for ease of construction steel was used for the frame proper with aluminium used to tie array rails together Barriers were specified to prevent corrosion of dissimilar metals wherever required by AS5033 2 2 Facility movement requirements were used to select appropriate pneumatic caster wheels pillow block bearings and the rotating steel array shaft Photovoltaic modules were selected for a compromise between high current production and small form factor Crystalline technology modules were suggested by the relevant project supervisors as the most applicable type for shading and hot spot experiments so a polycrystalline module was selected 26 Figure 3 5 Detailed design Facility frame with tilted array 12 Table 3 Detailed design Facility physical dimensions Physical Dimension Measurement Value Facility Length 2100mm Facility Maximum Width 2132mm Facility Maximum Height 2300mm Array Minimum Tilt Angle 5 degrees from horizontal Array Maximum Tilt Angle 65 degrees from horizontal
97. r resistance e Rep is the bulk p type resistance Ronis the contact to n type semiconductor resistance Rosnisthe bulk n type resistance 7 57 Power lost through any simple resistance be modelled through Ohm s law Any module series resistance will reduce the available fill factor and large series resistance values may reduce the module short circuit current 22 For a good solar cell the series resistance should be very small to operate with a reasonably efficiency for a reasonable return on investment The module series resistance was not an essential parameter for design of the Facility because the longest string length possible would be four modules but was instead supplied in the Facility Data Sheet as a key value for student models and experiments that examine the efficiency of Facility photovoltaic modules Figure 5 7 shows the net series resistance of each module to be less than 0 720 For 36 cell modules such a value of Rsgrizs is reasonable Rsenigs 0 720 0 700 5 0 680 e S 0 660 ha 0 640 n 0 620 N 0 600 0 580 1 2 3 4 5 6 7 8 9 PV Module Identification Number Figure 5 7 Series resistance comparison between PV modules 58 5 1 8 MODULE SHUNT RESISTANCE A shunt path may exist for current flow across the photovoltaic cell junction due to surface effect or a poor junction This alternate path for cell current constitutes a shunt resistance Rp across the junction Therefore
98. reater than the alternative option to purchase a ready made system that did not meet the entire scope of project such as the Amatrol PV Troubleshooting unit 11 3 1 4 3 LEGAL FEASIBILITY A short legal feasibility study was performed to ensure that relevant standards and regulations can be met wherever possible The Facility represents a special case that more closely resembles a test bench than a power generation facility explicit compliance with some standards or regulations may be deemed unnecessary by project supervisors In particular AS5033 3 3 4 specifies the requirement for string overcurrent protection based on a comparison to module maximum overcurrent protection rating 9 a specification required by IEC61730 2 to be published in the documentation of photovoltaic modules Unfortunately the vast majority of modules available for use on the Facility did not include this mandatory specification on any published documentation attempts were made to contact the relevant manufacturers but were unfruitful After discussion with project supervisors it was determined to move the project forward by assuming the greatest tolerable module maximum overcurrent protection ratingto be three times the short circuit current at STC This decision was made with the caveat that a shading device may be required to limit current production during fault current experiments involving more than three parallel strings on cold days with very high incoming solar ra
99. rings shall placed where string cables join the sub array or array cables in the string combiner box Array overcurrent protection shall be installed where array cables join the application circuit or the PCE In ELV arrays overcurrent protective devices where required for string and sub array cables shall be placed in either the positive or negative conductor the number of current carrying conductors minus one Where the extra low voltage array is earthed the protective devices shall be installed in all unearthed current carrying conductors AS5033 3 4 describes protection requirements against earth faults In general such protection is not required as the project scope requires the Facility to deliver ELV to student accessible areas and the system is not connected to an inverter or functional earthing of any kind On a similar note AS5033 4 4 2 describes necessary arrangements for systems functionally earthed floating and requiring lightning protection Systems under ELV that do not include a c modules or micro inverters with LV output that are not required to be earthed for lightning protection are not required to have protective earthing or bonding installed AS5033 3 5 lists requirements for protection against lightning and overvoltage Lightning protection is generally only required where systems are installed on buildings unlike the portable frame system required for the Facility However AS5033 3 5 2 remains relevant in
100. rrent production of any series connected modules lpm 3 44 3 42 3 40 3 38 3 36 3 34 3 32 3 30 3 28 3 26 3 24 1 2 3 4 5 6 7 8 9 PV Module Identification Number Current at Maximum Power A Figure 5 3 Maximum power current comparison between PV modules 33 5 1 4 MODULE VOLTAGE AT OPEN CIRCUIT The module voltage at open circuit is the voltage for maximum electrical load in the circuit 7 The open circuit voltage can be related to the simple electrical circuit model used in Chapter 02 by the following simplified equation where Io is the saturation or leakage current Without an external circuit the incoming solar radiation photons will still produce electron hole pairs within each photovoltaic cell the holes and electrons still move towards the doped p and n layers but can proceed no further without a complete circuit The voltage difference between the front and back of the cell will become large enough to flatten the barrier sufficiently to allow some holes and electrons to leak back When the number of carriers leaking back is equal to the number being generated by the incoming light an equilibrium voltage has been reached 21 The voltage at this equilibrium point is the open circuit voltage and does not experience large variances in response to changes in solar radiation intensity In industry the open circuit voltage is used when considering the maximum potential output voltage of a photovoltaic instal
101. s Standard is applicable to almost any electrical installation used within Australia At all times AS3000 must be adhered to with explicit protection systems enforced wherever required or suggested by the Wiring Rules This Standard specifies that any electrical installation shall be designed to protect persons livestock and property from harmful effects function correctly as intended minimise inconvenience in the event of a fault and facilitate safe operation inspection testing and maintenance for the life of the system Full details of the AS3000 requirements on the Facility are listed in APPENDIX B 12 2 1 9 453008 1 2010 ELECTRICAL INSTALLATIONS SELECTION OF CABLES AS3008 1 defines methods for cable selection for common cable use up to and including 600 volts at 50 hertz a c based on current carrying capacity voltage drop and short circuit temperature rise Although this Standard deals with a c cable selection it is suggested as a guide by AS5033 for cable selection throughout the Facility 9 AS NZS 3008 1 series applies to a c cables but for the purposes of AS 5033 the current rating tables and calculations are relevant also for d c 9 This standard defines minimum ratings for cables that must be adhered to atall points on the Facility 2 2 Available Products and Components A survey of parts and components available for use on the Facility was conducted This research would be particularly important as a gre
102. s are available for a number of poles Of particular note were the Telergon eight pole lockable d c isolators capable of isolating eight separate circuit elements at the same time Various Banana XLR and other Plug Socket Data Sheets A large number of sockets and connectors were available however sockets with documented current and voltage ratings proved difficult to find Rated plugs and sockets would be required to demonstrate that student interaction elements of the Facility would be safe to use ABB Overcurrent Protection Devices Overcurrent protection devices are available in a number of configurations such as fast breaking slow breaking etc A balance may be found between compliance with legal regulations adequate student protection and operational feasibility BlueSea Push Button Circuit Breaker Specifications BlueSea breakers were the only available d c overcurrent protection devices for low nominal currents 14 2 3 Existing Projects and Systems A number of photovoltaic oriented projects have previously been conducted at Murdoch University Thesis report documents are available for many of these systems and were examined for insight on potential challenges or roadblocks that may impact this project These projects included but were not limited to Thesis Project Stuart Kempin o Kempin Stuart 2012 A Photovoltaic Training Facility On The Murdoch University Engi
103. s implications for usable array angles 33 CHAPTER 04 FACILITY CONSTRUCTION 4 1 Component Acquisition Components were sourced from local industry suppliers wherever possible to maximise available support from local industry where any issues could be discussed in person manufacturing facilities could be inspected faulty components could easily be returned and relationships between Murdoch University and members of local industry established or reinforced Local industry wholesalers were canvassed and SolarMatrix selected for most attractive component pricing and most helpful service SolarMatrix supplied as many photovoltaic industry components as possible including array cables conduit connectors module mounting hardware d c isolators and overcurrent circuit breakers National wholesaler RS Components was selected to supply enclosures internal wiring terminals sockets and some overcurrent protection devices Local retailer 12 Volt Shop was the only supplier with stock ofa suitable photovoltaic module and low current over current d c breakers Local specialist printer ImageSource took on the challenging task of printing and machining the plastic control panel backgrounds Every attempt was made to purchase components from wholesalers or distributors to minimise costs and access higher quality parts than those available from local electronics supply stores but a small number of components were only available from retail outlets At a
104. scover faults or verify that the installation is operating correctly It may also include the process of applying testing instruments or devices to various parts of the electrical installation and equipment to determine how the electrical installation and equipment is operating 3 Fault finding is an important activity to understand for any photovoltaic system designer operator or service technician as dangerous faults on photovoltaic arrays can be invisible to the lay man and difficult to detect A need therefore exists for a practical teaching tool to be implemented for use in these and future courses This tool would take the form of a Photovoltaic Array Troubleshooting and Training Facility a small configurable array of photovoltaic modules with a range of measurement testing and logging capacities available to students The purpose of this thesis project was to fulfil this need through the design construction testing and delivery of such a teaching tool 1 2 Document Structure This document shall follow a basic structure that can be simplified as introduction background core and synthesis The introduction explains what the thesis project is about the problems solved by this project the aims and scope and a brief overview of the thesis report The background reviews knowledge required for a reader to understand the project including photovoltaic theory practice and relevant legal requirements The core section deals wi
105. sed on the system proper Each module was compared to the others to determine which would be designated spare In the interest of brevity one module shall be compared with the chosen spare here Table 5 Parameter comparison for photovoltaic modules one and two Data Parameter 1 2 Unit Sheet Pmax 60 3 62 15 60 80 W Vpm 17 50 18 21 18 40 V Ipm 3 43 341 3 30 Voc 22 0 22 58 22 61 V Isc 3 80 3 62 3 52 Fill Factor 0 72 076 0 76 Rseries 0 662 0 635 Q Rshunt 712 1122 60 Photovoltaic module one is a suitable unit for the Facility array The module produces acceptable magnitude of power even though the voltage at peak power is higher and the current at peak power lower than specified on the manufacturer data sheet The PV and IV curves shown in Figure 5 9 exhibit reasonably model characteristic shapes with a better fill factor than specified by Yingli Solar Sun simulator test results show the parameters and characteristics of module one to be approximately in line with almost all of the photovoltaic modules purchased for the Facility PV Module 1 Current Amps Power Watts Voltage Volts Figure 5 9 IV and PV plots for PV Module 01 By comparison photovoltaic module two is the least suitable unit of those available for installation on the Facility array While module two series and shunt resistance values were better than most of the modules t
106. students or researchers e Expand the sensor panel with a greater number of applicable sensors in the plane of the array ambient and module cell temperatures wind speed and direction etc Integrate these sensors with the tilt control mechanism to automatically track for the best power generation based on environment conditions Tilt control movements should not present any danger to students operating the Facility e Expand the logging capabilities of the Facility Two unused current shunts have been fitted within Wiring Enclosure A for additional current measurements as many logging devices have difficulty measuring large currents A serial port or similar could be added to the Facility to provide a connection means for Arduino DataLogger or similar devices 75 WORKS CITED 11 21 3 Institute Australian in Australia Report 2014 APVI June 2015 APVI IEA2015 M Calais Thesis Meeting Email Correspondence K Peters Ed ed 2014 Standards Australia AS 4836 Safe working on or near low voltage electrical installations and equipment ed SAI Global Limited 2011 S Krauter Solar electric power generation Springer 2006 Luque and S Hegedus Handbook of photovoltaic science and engineering United Kingdom Wiley Blackwell an imprint of John Wiley amp Sons Ltd 2011 Transport Solar World Wafer ed flickr Oregon Department of Transport 2009 G N Tiwari S Dubey and J
107. t protection installed to minimise damage by large battery fault currents Wherever possible said fault protection should be installed as close as possible to the battery AS5033 2 1 8 postulates that fault currents may flow due to prospective fault conditions within a PV array These fault currents depend on the number of module strings fault location and irradiance level Short circuit detection can be very difficult in photovoltaic arrays as fault currents may be just slightly higher than nominal operating currents Possibilities of line to line faults earth faults and inadvertent wire disconnections in the array need to be minimised wherever possible AS5033 2 1 9 considers module operation at elevated temperatures Modules can be expected to operate at approximately 25 C above ambient temperature in a typical installation with very good ventilation receiving incoming solar radiation at approximately 1000Wm 9 Photovoltaic modules can be expected to operate at elevated temperatures and all components and equipment that may be in direct contact or near the PV array conductors PCEs connectors etc need to be capable of withstanding the expected maximum operating temperature of the array AS5033 2 2 specifies relevant requirements for mechanical and frame components with regards to thermal and corrosion concerns for the location at which the array is to be installed Mounting arrangement of modules and other metallic components should
108. t safety limits Simple schematics and diagrams were designed for 25 basic configuration appropriate facility components found Sample preliminary design diagrams are shown APPENDIX and APPENDIX G The detailed design was to be heavily influenced by availability of certain components such as modules fuses and sockets preliminary design choices were made for certain components to create a starting point for the detailed design 3 2 Detailed Design After a brief consultation with the relevant project supervisors all preliminary designs were approved and the project could continue to detailed design phase This design period used the preliminary design choices as a starting point to produce a sufficiently detailed plan for construction work to commence Strict external Facility dimensions were declared given restrictions including door widths and elevator dimensions These restrictions are non negotiable as widening of elevators and hallways was not an option The facility was therefore sized to be as wide as possible for maximum stability at the dimensions listed in Table 3 Yingli sixty watt square form factor photovoltaic modules were selected for a balance between maximum current maximum number of potential parallel strings and module physical dimensions with the physical dimensions being the decisive factor for module suitability Three modules side by side would fit inside the elevator so a total of eight phot
109. t was conducted the results of this evaluation are shown in 21 Table 2 The general result of this technical feasibility study was positive Murdoch University has access to the required technical resources to successfully see this project through to completion 22 Table 2 Technical feasibility matrix Technical Skill Expertise or Tool Applicable Murdoch University Sufficient Required for Project Option Available for Project Yes No Tertiary study level research skills Skills provided by Mr Kieran Peters Yes under advisement by Dr Trevor Pryor and Dr Martina Calais Access to Australian Standards Murdoch University subscription to SAI Yes Global Standards with online access Access to PV Module reference texts Texts and Online Text Access provided Yes and Installation reference texts by Murdoch University Access to component Data Sheets Data Sheets provided in most cases by Yes Retailer Wholesaler Distributor or Manufacturer Access to suitable design software Software tools Microsoft Visio Yes tools SpiceNet Microsoft Excel etc provided by Murdoch University Component purchasing procedure Purchase Order procedure determined Yes structure and experience by Murdoch University Supplier contacts provided by Mr Kieran Peters Finance process advice provided by Ms Jann Rizkallah and Ms Miriam Everall Essential basic Hand and Power Tools Tools provided by Mr
110. tandard wiring to students on all facilities and projects and the Facility is no exception Wherever possible cables were installed with neat bends secured in logical groups and colour coordinated to represent active bypass and return circuit stages red blue and black respectively Such a colour scheme ties the enclosure design language to the array cable design language and should assist future technicians in troubleshooting or maintaining Facility components Enclosure wiring was routed in such a way that each mutually exclusive experiment is isolated from the other with completely separate cables components mounting rails and isolation devices used for each experiment control panel This ensures that any maintenance issues or breakages that occur to one experiment shall not influence another experiment a requirement of AS3000 18 Experiment circuits both receive current from the same teamed terminals located horizontally across the bottom rail in Enclosure A Figure 4 14 with Enclosure B connecting to the photovoltaic array through interconnections between the two enclosures as shown in Figure 4 15 45 Figure 4 15 Wiring enclosure back plate installation and interconnection 4 2 6 CONTROL PANEL CONSTRUCTION Control panels were constructed of a six millimetre thick Opal brand polycarbonate that is graffiti resistant capable of handling temperatures over eighty degrees Celcius and strong enough to prevent cracks or da
111. tene tnnnnn tenen 57 FIGURE 5 7 SERIES RESISTANCE COMPARISON BETWEEN PV MODULES eese tnnt 58 FIGURE 5 8 SHUNT RESISTANCE COMPARISON BETWEEN PV MODULES eerte tnnt 60 FIGURE 5 9 IV AND PV PLOTS FOR PV MODULE O1 ttennnttnnnnttnnnt ttn nt ttn nitet nt tite 61 FIGURE 5 10 IV AND PV PLOTS FOR PV MODULE 02 sese ttennn tnnt ttnnntttns ntt 62 FIGURE 5 11 FACILITY CONTROL PANEL SECTION REQUIRED FOR SAMPLE EXPERIMENT 01 63 FIGURE 5 12 MANUAL LOAD CONNECTION CONTROL PANEL LAYOUT esent 64 FIGURE 5 13 MPPT LOAD CONNECTION CONTROL PANEL LAYOUT tenente 64 FIGURE 5 14 UNSHADED PHOTOVOLTAIC MODULE 23 65 FIGURE 5 15 SUGGESTED PARTIAL SHADING PATTERN FOR PHOTOVOLTAIC MODULE 24 65 FIGURE 5 16 SAMPLE EXPERIMENT 01 IV AND PV CURVE RESULT FOR THREE PARALLEL MODULES 67 FIGURE 5 17 EQUIVALENT CIRCUIT MODEL DIAGRAM FOR SAMPLE EXPERIMENT 02 68 FIGURE 5 18 CONTROL PANEL B LAYOUT SHOWING COLOURED BANANA SOCKETS 902 69 FIGURE 5 19 STRING CURRENT MEASUREMENTS FOR SAMPLE EXPERIMENT 02 UNDER VARIOUS LOADS 71 V LIST OF TABLES TABLE 1 SIMPLIFIED COMPONENT 0 13 TABLE 2 TECHNICAL FEASIBILITY
112. th the design construction testing and experiment results of the project The synthesis draws together the results of the project to summarise the work and evaluate the degree to which the Facility solves the problems identified in the introduction The basic structure relates to the chapters ofthis document as shown in Figure 1 2 below CHAPTER ELZN ELS Figure 1 2 Document structure and relationship to Chapters This page is intentionally left blank CHAPTER 02 RESEARCH AND LITERATURE REVIEW 2 1 Photovoltaic Module Research 2 1 1 THE PHOTOVOLTAIC EFFECT A solar cell is a large semiconductor diode The cell shown in Figure 2 1 consists of a p n semiconductor junction created by doping a semiconductor crystal with impurities boron and phosphorous are frequently used sunlight metal grid amm antireflective layer metal contact _ Figure 2 1 A simplified solar cell showing creation of hole electron pairs Within the crystalline structure of a crystalline photovoltaic cell atoms require four valence band electrons to bind with the structure The n region contains many free negative charges as the introduced impurities have a greater number of valence band electrons than the four required This results in a region of weakly bonded electrons that could move in a conduction band as current if provided with enough energy This energy could be supplied by photons particles
113. ting strings feed the load and excess current is fed into the fault backwards through Module A After a few minutes String AB Breaker actuated and the faulty string was shut down this actuation took longer because the fault current was not a great deal larger in magnitude than the nominal operating current for a breaker sized in accordance with AS5033 3 3 4 The time overcurrent curve for a Curve D ABB 71 6A DC breaker shows that currents so close to nominal may take up to twenty minutes to cause the breaker to actuate It is particularly interesting to note that under a heavy load in this case the MPPT Load and a large 12V winch String AB sees almost no reverse current the overcurrent breaker will never actuate This highlights one of the important safety issues faced by photovoltaic modules where faults may exist and be difficult to detect without a detailed inspection Such an experiment may be used to impress upon students the importance of care and attention when approaching photovoltaic installations and demonstrate the need for careful design when engineering solar generation systems 72 This page is intentionally left blank 73 CHAPTER 06 CONCLUSIONS AND RECOMMENDATIONS 6 1 Project Conclusion A need was shown to exist for a practical teaching tool to be implemented for use by Murdoch University courses involved with photovoltaic system design This tool was to take the form of a specialised configurable array o
114. ts for hidden array faults to be made Fault connections would be made by a laboratory instructor connecting nodes on the array to a load breaking heavy duty d c isolator through a current shunt The isolator would permit the fault to be engaged or disengaged as required A means of safe current measurement would be provided by the shunt permitting measurements using current limited handheld devices The Enclosure is designed such that no student shall have access to or vision of the array faults with the exception of operating the fault isolation switch on the Facility exterior Students shall not be able to determine the location of the fault s without undertaking a series of measurements Wiring Enclosure B shall also house the terminals for MPPT load connection battery overcurrent protection breaker and manual load connection the same load connection points are provided on Control Panel B as Control Panel A Wiring enclosure B would also house four small d c overcurrent protection breakers for 3A 5A 6A and 7A nominal currents to permit individual strings to be connected by a student to these breakers for photovoltaic array overcurrent protection device operation experiments As with Control Panel A the full three level wiring diagram for Control Panel B is included in APPENDIX L APPENDIX and APPENDIX N Bypass diode experiments require the ability to install and uninstall bypass diodes on command Providing student access to the stan
115. vices that automatically disconnect the supply in the event of overcurrent before such overcurrent attains a magnitude or duration that could cause injury to persons or livestock or damage because of excessive temperatures or electromechanical stresses in the electrical installation 18 The Standard does not provide explicit details for ELV circuit requirements so every effort shall be made to ensure that overcurrent protection devices are installed to limit risk to any person using the Facility AS3000 2 5 3 1 specifies that a certain coordination must be designed between conductors and protective devices such that Ip lt Iy lt Iz I 1 451 where e Isis the maximum demand current e Inis the nominal current of the protective device e 215 the continuous current carrying capacity of the conductor and e L is the current ensuring effective operation of the protective device May be considered 1 451 18 This specification ensures that the current carrying conductors in an electrical installation are rated for currents suitably higher than or equal to the demand current and protection device nominal current ratings 83 AS3000 1 5 10 requires that protective earthing conductors be capable of carrying earth fault currents without reaching excessive temperatures AS3000 2 3 2 1 2 requires that all poles of a d c circuit shall be capable of being isolated by a device for isolation 18 However switches in
116. would not operate an overcurrent device 9 Although arcing is unlikely in this experiment great care should be taken that all electrical connections are checked for tightness At all times a one hand behind 68 your back approach should be taken to minimise risk of fault current flow through two arms through a student s torso Covered sturdy shoes and sun protection shall be required p r r I I I I I I I I I I v 24 ET es bi 1 5 x ri 1 3 5 I lt 2 a c P 8 5 M A MA R7 I ea I 2 E 2 l 4 I I lo El le Current Shunt Figure 5 18 Control Panel B layout showing coloured banana sockets 69 10 11 12 13 14 15 16 5 3 2 4 METHOD Connect four UniT DMMs as ammeters inline for each string on the module circuit diagram by bridging the yellow connection banana sockets in Figure 4 18 with banana leads These DMMs shall display the current movement through each string Connect a fifth DMM to the yellow banana sockets on the negative of the module circuit and measure the voltage across these terminals This element is a current shunt as shown on t

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