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![When installing, commissioning, and executing maintenance on PV systems, technicians verify safety and
performance per IEC 62446-1 standards
Safety
IEC 62446-1 requires that the AC circuits are tested first, then the following six DC circuit tests need to be
performed, preferably in this order:
1) Test continuity of equipment and system grounding conductors
2) Test polarity of all DC cables
3) Test open-circuit voltage [Voc] for each PV source circuit
4) Test short-circuit current [Isc] for each PV source circuit
5) Test functionality of major system components
6) Test the insulation resistance of the DC circuit conductors
Performance
7) I-V Curve tracing and associated software analysis
IEC Testing Requirements for PV Systems
Utilities & 3rd
Party Service
Techs
PV Installers &
Maintenance Techs](https://image.slidesharecdn.com/toolstechniquesforcommissioningandmaintainingpvsystemsw-animationsfinal-240618195906-ad1e980b/75/Tools-Techniques-for-Commissioning-and-Maintaining-PV-Systems-W-Animations-Final-pptx-8-2048.jpg)
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Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations Final.pptx
- 1. Tools and Techniques forCommissioning and Maintaining PV Systems
- 2. • Review CATratings and how they apply to solar • Overview of IEC 62446-1 testing requirements • Analyze the solar workflow, what tests are used at each step, and the tools used to perform those tests Course Learning Objectives
- 3. • What isa transient? • Momentary unwanted spike in voltage • What causes a transient? • Motor or another inductive load switching off • Equipment malfunction • Utility load switching • Adjustable speed drives • Lightning strike • Transients • Are invisible and largely unavoidable • May last under 100 mS, but can be extremely dangerous • May overcome test equipment input protection, causing an arc/short in the tester Transient Voltages (Voltage “Spikes”) 480 V rms, ± 678 V peaks Spikes up to 8,000 Volts
- 4. • Understanding OvervoltageInstallation Category (CAT I to IV) is key when choosing test tools • Solar arrays are permanently wired electrical installations (IEC 61730-1) • Overvoltage CAT III • Not point-of-use electrical outlets (CAT II) • The standard for PV modules defines the insulation, creepage, and clearance requirements as CAT III • Requires a CAT III instrument to test it • Within a category, a higher voltage rating denotes a higher transient withstand rating • E.g., a CAT III 1500 V meter has superior protection compared to a CAT III 1000 V rated meter • To ensure the safety of you and your team, always choose a tool rated for the highest category you could potentially use it. CAT Rating in Solar installation CAT III CAT IV CAT IV CAT III / II
- 5. • First, knowthe category you are working in, then choose the appropriate voltage rating. • The working voltage could be 300 V, 600 V, 1,000 V, or 1,500 V • Equipment should be dual-rated, meeting both CAT and voltage requirements • Make sure your test leads and probes have a matching rating • Voltage rating by itself can be misleading • CAT III 1,000 V (withstands 8,000 V transient) is safer than CAT II 1,000 V (withstands 6,000 V transient) • Some meters are rated for a high voltage I.E., 1,500 V but have a lower CAT rating, they aren’t designed/tested to the higher CAT rating CAT Rating Voltage Rating
- 6. Look for CATmarkings between input jacks The test equipment should be independently tested, marked, and certified. CAT III 600 V CAT III 1000 V CAT III 1500 V
- 7. • “Listed” vs.“designed to” • IEC sets standards but does not test or inspect for compliance. • A manufacturer can claim to “design to” a standard with no independent verification. • To be UL listed, or CSA or TÜV certified, a manufacturer must employ the listing agency to test the product’s compliance with the standard. • Look for the listing agency’s emblem on the meter. • Meter must be independent tested, marked, and certified. Independent testing and certification
- 8. When installing, commissioning,and executing maintenance on PV systems, technicians verify safety and performance per IEC 62446-1 standards Safety IEC 62446-1 requires that the AC circuits are tested first, then the following six DC circuit tests need to be performed, preferably in this order: 1) Test continuity of equipment and system grounding conductors 2) Test polarity of all DC cables 3) Test open-circuit voltage [Voc] for each PV source circuit 4) Test short-circuit current [Isc] for each PV source circuit 5) Test functionality of major system components 6) Test the insulation resistance of the DC circuit conductors Performance 7) I-V Curve tracing and associated software analysis IEC Testing Requirements for PV Systems Utilities & 3rd Party Service Techs PV Installers & Maintenance Techs
- 9. Let’s walk througha solar workflow in stages O&M Commissioning Installation Permitting System Design Site Survey Solar Tests and Measurements: Voc and Isc: 1, 2, 5 I-V Curve Tracing: 1, 2 Temperature: 1 Irradiance: 1 Tilt Angle: 1 Insulation Resistance: 1, 2, 5 Continuity: 1, 2, 5 Ground fault: 1, 2, 5 Power Quality: 7 Battery Testing: 4 AC Testing: 5, 7 Solar Toolbelt: Clamp Meter Irradiance Meter I-V Curve Tracer Insulation Resistance Tester (IRT) Installation Tester Thermal Camera Battery Analyzer
- 10. • Insulation resistancetesting (IRT) • Used to verify the integrity of the insulation after the wire is installed • Can also be used to identify ground faults • IRT meters send high voltage through conductor and measures leakage to ground • Finds damage before it becomes a larger issue • Appropriate tools • Insulation resistance testers like Fluke 1587FC, 1507 FC • Multifunction tools like Fluke SMFT-1000 Wire Installation
- 11. • DC Vocand polarity • Testing Voc will identify miswired strings • High voltage = too many modules in series • Low voltage = too few modules in series • Testing polarity will ensure that module home runs are landed properly • Appropriate tools • Digital multimeter or clamp meter rated for system voltage • Fluke 393 FC, Amprobe HD-160C or HD-110C, Fluke SMFT-1000 Commissioning – Voltage and Polarity
- 12. • I-V curvebaseline testing • Identifies any module/string issues before operation • Creates historical record for future comparison • Can identify issues not seen with Voc testing • Appropriate tools • I-V curve tracer or multifunction tool with I-V curve tracing • Fluke SMFT-1000 • Solmetric PVA-1000S, PVA-1500T, PVA-1500HE Commissioning – I-V Curve Testing
- 13. • Lo Ohms(Lo Ω or Rlo) • Measure resistance/continuity between two points • Module frame to ground rod, between two tables • Low resistance is ideal • Ensures that non-current carrying metal parts are bonded together • Appropriate tools • Fluke SMFT-1000 • Fluke 1507 Commissioning – Earth-Bond Continuity
- 14. • Measure equipmentgrounding system resistance to ground • Ensures grounding system has a low resistance connection to the earth • Ungrounded parts may pose a safety hazard if there’s a ground fault • Appropriate tools • Fluke 1630, 1625-2 Commissioning – Ground Resistance Testing
- 15. Commissioning – PerformanceTesting • Expected vs. actual power measurements • Inverter efficiency verification • Ensure the system is operating properly • Set baseline data for future testing • Appropriate tools • Fluke 393 FC • Measures DC power • SMFT-1000 • Measures DC & AC power, calculates inverter efficiency
- 16. • Electrical equipment •Disconnects, combiners, inverters, transformers • Modules • Aerial or handheld • Module interconnects • With system operating at high irradiance • TI testing requires training Commissioning/O&M – Thermal Imaging
- 17. • Hot equipment= increased resistance • Cool equipment = no/low current • Set baseline to ensure proper operation and create historical record • Appropriate tools • Aerial TI cameras • Drone-based or fixed wing • Handheld TI cameras • Fluke Ti480 Pro, TiS55+, PTi120 Commissioning/O&M – Thermal Imaging The circuit is cold because there’s no circuit connected.
- 18. • Inspect installationto identify any maintenance issues • Easy way to find problems like burnt-out connectors, module damage • Appropriate tools • Trained inspector • Workflow checklist O&M – Visual Inspection
- 19. • DC voltageand current • AC voltage and current • Fuse continuity • Thermal imaging • Torque terminals • Inverter efficiency • AC power quality • Voltage, frequency, harmonics O&M– Inverters, Transformers
- 20. • Ensures equipmentis operating properly • Upholds OEM warranty • Prevents future failures • Maximizes system production • Appropriate tools • Digital multimeter • Clamp meters • Torque tools • Multifunction testers O&M– Inverters, Transformers
- 21. PV system designsshould minimize harmonics. However, if you suspect harmonics problems in your facility, you can use a power quality analyzer to troubleshoot the system. Benefits of the PQ analyzer • Troubleshooting and preventing problems in power generation, transmission, and distribution systems • Conducting load studies to reduce energy usage • Measures at 5x second or every 200ms O&M - Harmonics issues Fluke 435-II Power Quality and Energy Analyzer
- 22. O&M – Modules •Visually inspect array for any obvious damage or accidental disconnections • Damaged modules • Compromised insulation • Loose or damaged connectors • Thermal imaging inspection • Aerial or handheld • Modules/cells not operating will be hot • High resistance connections will be hot • Identify equipment for further testing
- 23. • Check voltageand current • Vmp testing can identify closed bypass diodes • Imp testing can identify strings that aren’t producing • Test circuits for current before disconnecting module connectors or opening fuses O&M – Modules
- 24. • Tools touse • Visually inspect • Check lists to ensure steps aren’t missed • Thermal imaging inspection • Drone with thermal camera • Handheld thermal camera • Check voltage and current • Digital multimeter • Clamp meter • Must be CAT III with voltage rating greater than array voltage O&M – Modules
- 25. • What isa ground fault? • An unintentional connection between a current-carrying conductor and a grounded metal part • Types of ground faults • Solid, always has a connection to ground • Intermittent, connection to ground comes and goes • Appear when array is wet or when a tracker moves into a specific position • Causes of ground faults • Pinched wires • Damage during wire pull • Insulation wears against sharp edge of rack or module O&M – Ground Faults
- 26. • Voltage testing •Positive to negative, positive to ground, negative to ground • Look for voltage to ground • Should be zero • May read some voltage initially (ghost voltage), but it should bleed off quickly • Insulation resistance testing • Used to identify strings with intermittent ground faults • Insulation resistance may meet IEC pass threshold but may be an outlier O&M – Ground Faults
- 27. • Ground faultscan create a safety hazard • Energized metal parts • Fire hazard • Lead to arc faults • Reduce system production • Appropriate tools • Digital multimeter • Clamp meter • Insulation resistance tester O&M – Ground Faults
- 28. Ground Faults –Voltage Testing – Positive to Negative 16 Modules Voc = 53.82 861.12
- 29. Ground Faults –Voltage Testing – Positive to Ground 16 Modules Voc = 53.82 645.84
- 30. Ground Faults –Voltage Testing – Negative to Ground 16 Modules Voc = 53.82 215.28
- 31. Meter Reading ÷Module Voc = Module Count Positive to Negative 861.12 ÷ 53.82 = 16 Positive to Ground 645.84 ÷ 53.82 = 12 Negative to Ground 215.28 ÷ 53.82 = 4 Ground Faults – Voltage Testing - Results 16 Modules Voc = 53.82 Ground fault between modules 4 and 5! Ground Fault Location
- 32. Meter Reading ÷Module Voc = Module Count Positive to Negative 861.12 ÷ 53.82 = 16 Positive to Ground 861.12 ÷ 53.82 = 16 Negative to Ground 0 ÷ 53.82 = 0 Ground Faults – Voltage Testing – Example 2 16 Modules Voc = 53.82 Ground fault on negative homerun! Ground Fault Location
- 33. • What isan arc fault? • A connection that causes an electrical arc • Two types • Series arc fault • High resistance when there should be low • High resistance module-to-module connection • Parallel arc fault • Low resistance when there should be high • DC positive to DC negative connection O&M – Arc Faults
- 34. • Visual inspection •Look for burn damage • Thermal camera • Detects high-resistance connections • Inverter fault code • Isolate strings • Restart inverter • Find string w/fault O&M – Arc Faults
- 35. • Serious safetyrisk • Electrical and fire hazard • Series arc faults will eventually burn out but may cause fire first • Parallel arc faults will continue until circuit is broken or current stops • Appropriate tools • Thermal camera • Troubleshooting workflow O&M – Arc Faults Source: Camelot Energy Group
- 36. • Test dataneeds to be recorded for future reference • Data must be easy to record, catalog, retrieve, and accurate • Workflows ensure consistent results, especially for new technicians Documentation
- 37. • Test equipmentmust be calibrated to ensure accurate measurements • Every year or to the manufacturer’s requirement • O&M contracts may require a calibration certificate Calibration
- 38. • Test andmeasurement tools must have the proper CAT and voltage ratings • Many tasks require different tests • The right tool for the job makes it go faster, safer • Calibrate your tools to ensure accurate measurements • Wear correct PPE and use properly rated and tested tools Summary
- 39. Q&A Time For moreinformation: solar.fluke.com Please send any questions you have right now using the question box in your webinar controls. After the webinar, if you think of any more questions, please feel free to contact me via email Katarina Ost: katarina.ost@transcat.com For related product information, go to: www.transcat.com/brand/fluke-store Thanks for joining us.
Editor's Notes
- #6 The voltage rating alone will not tell you how well that meter was designed to survive high transient impulses. The most important single concept to understand about the standards is the Overvoltage Installation Category In DC systems: Fault current is not infinite, not very high – That’s why CAT III and not CAT IV
- #23 Need to find a good way to summarize and end