Photovoltaic System Commissioning and Testing

1 Photovoltaic System Commissioning and TestingA guide for PV System Technicians and EngineersThe PV150 SolarlinkTMTest Kit contains more than simply the tools to meet all the Commissioning test requirementsof NABCEP and other international standards. It holds the secret to making it more efficient, easier and between the PV150 tester and Solar Survey 200R irradiance meter, allows irradiance,module and ambient temperature results from the 200R to be transmitted over a wireless link and be recordedin real time in the PV150. This is the only PV installation tester with all of the PV electrical test functions in onehand-held unit. And now, you can improve speed and traceability by downloading all results via USB. The solution to gaining the competitive edge? It s in the now, contact us for full details oremail safer, traceable solar PV Testing .

2 It s in the Codes and Safety42 PV System PV Module Response to Response to Rating PV Types of PV Systems123 System Documentation144 Commissioning PV Final Installation Visual Labels and Markings185 System Testing and Continuity Polarity Voltage and Current Open-Circuit Voltage Short-Circuit Current Insulation Resistance System Functional Test Reports306 System Performance Verifying Power and Energy Verifying AC Power Verifying AC Energy Array I-V Other Power Quality Thermal Inverter Efficiency Maximum Power Point Tracking Shading Analysis387 System Troubleshooting41 Contents1 INTRODUCTION Solar Photovoltaic (PV) systems are beinginstalled in ever increasing numbers throughoutthe world, and are expected to safely and reliablyproduce electrical energy over several decades ofoperation.

3 However, many systems are notsatisfactorily evaluated prior to being placed intoservice, and many have had little, if any,scheduled maintenance or Testing over theirlifetime. Unfortunately, this often leads to unsafeand underperforming systems with reduced valueto their owners. Any electrical System can be tested to verifyperformance and to evaluate the condition of thewiring systems and equipment. This is particularlyimportant for PV installations, which are subjectedto extreme environmental conditions anddeteriorating effects of the elements over manyyears. To help ensure the long-term safeoperation of these systems, quality PV installationand service contractors execute a thoroughcommissioning process followed by a regularperiodic Testing and maintenance practices can help promote safety andoptimize performance, and provide essentialinformation required to effectively troubleshoot,diagnose and remedy problems with the System .

4 All PV systems require Testing for performanceand safety verifications. The level of testingrequired will depend on local regulators, thecustomer desires, and quality commitments ofinstallation and maintenance contractors. Thisdocument provides an overview of thecommissioning and Testing process, and appliesgenerally to interactive PV systems that areinterconnected to the utility grid. It addresses theapplicable codes and standards, in addition totesting equipment, procedures, and interpretationof the results. See Figure 1. EnergySourceEnergyConversionPV ArrayPV ArrayPowerConditioningPowerDistributionE lectricalLoadElectricUtilityEnergyStorag e(optional)PV ArrayInverterLoadCenterBatteryFigure 1. PV System Codes and Standards The National Electrical Code (NEC), NFPA 70governs the requirements for most non-utilityelectrical installations in the , including solarphotovoltaic (PV) systems.

5 When adopted intothe building codes by states or local jurisdictions,the NEC becomes the basis for inspections andapprovals of electrical installations. Chapters 1 4 of the NEC generally apply to allelectrical systems, covering installationrequirements, wiring and protection, wiringmethods and materials, and equipment forgeneral use. Article 690 of the NEC covers specialinstallation requirements for solar photovoltaicsystems, however many other articles also , Article 705 covers requirements forthe interconnecting PV systems and otherdistributed generation equipment to othersources, such as the utility grid. While the NEC does not specifically address PVsystem performance, it does establishrequirements for the overall quality and safety ofelectrical installations.

6 Many of theserequirements can be verified through visualinspections and a review of the System designand installation documents. However, certainNEC requirements can only be validated byelectrical tests and measurements. Theseinclude verifying the continuity of groundingsystems, verifying System voltages and currents,and measuring insulation resistance to determinewiring integrity. Other standards also apply to the Testing andcommissioning of PV systems. Compliance withthese additional codes or standards may berequired by local authorities, or requested bybuyers, lenders or underwriters to help ensure thehighest levels of safety, quality and performancefor PV international standard IEC 62446 GridConnected PV Systems Minimum Requirementsfor System Documentation, Commissioning Tests,and Inspectiondefines minimum documentation, Commissioning tests and inspection criteria forgrid-connected PV systems.

7 Information derivedfrom this standard is intended to verify the safeand proper operation of PV systems, and to serveas a guide for designers, installers and servicepersonnel. This IEC standard covers specificrequirements for Testing and Commissioning PVsystems not addressed by the NEC and otherelectrical installation codes, such as IEC 60364:Electrical Installations for Buildings. Section 712of IEC 60364 addresses specific requirements forsolar Photovoltaic (PV) power supply systems. Compliance with the IEC 62446 standard isrequired for many PV projects in Europe andsimilar requirements are being listed inprocurement documents for new projects in Many of the Testing procedures outlined inthis standard correlate directly with NECrequirements for the verification of safety for allelectrical systems, which are addressedthroughout this document.

8 NFPA 70B Recommended Practice forElectrical Equipment Maintenanceprovides guidelines on test methods andthe preventive maintenance of electricalsystems. This standard can be used inpart to help verify NEC requirementsthrough electrical System measurements Safety Conducting electrical Testing on any PV systemshould be performed by qualified individualshaving knowledge and experience with electricalsystems measurements, the test equipment used,the equipment or systems being tested, and anawareness of the hazards involved. Working withPV systems involves exposure to energizedcircuits with high voltages and potentially lethalcurrents, presenting electrical shock systems and higher voltage installationscan also present electrical burn and arc flashhazards.

9 When these electrical hazards arecombined other hazards such as working atheights and in difficult locations exposed to theelements, it is imperative for those installing andservicing PV systems to follow all applicable safetystandards and Occupational Safety and HealthAdministration (OSHA) issues and enforcesstandards in the for worker safety and healthin the In particular, OSHA regulations coveredin CFR 29 Part 1926 Safety and HealthRegulations for Construction address a broadscope of safety hazards likely to be encountered inconstructing and maintaining PV installations. Thestandards can be freely downloaded from theOSHA website, see: OSHA regulations require that employers providea safe and healthy workplace free of hazards, andfollow the applicable OSHA standards.

10 Employersmust provide safety training to affected employeesaddressing all probable hazards on a constructionsite. Workers are responsible for following theemployer s safety and health rules and wearingand maintaining safety gear as instructed. AnOSHA 10-Hour Construction Industry Trainingprogram covers the requirements for avoiding andmitigating a number of jobsite safety hazardsaddressed in 29 CFR 1926, including electricalsafety, personal protective equipment (PPE), fallprotection systems, stairways and ladders, handand power tools, cranes and lifts, excavations,scaffolding, and practices for preventing electrical hazardsand other common safety hazards associatedwith PV installations include the following: Carry out a risk assessment beforeconducting any work at the site.