IEC 62446-1 Summarized
IEC 62446-1 establishes the standard for testing, documenting, and maintaining grid-connected PV systems. We have summarized it below for easy processing and integration into your processes!
IEC 62446 Test | Purpose | Instrument | Challenges for Operative Systems | Recommendation |
Grounding System Continuity Test | Ensure that parts of the PV system frame, rack, boxes are grounded. | Ohm-meter or continuity tester | No Problems | Check continuity of ground in any preventative maintenance inspection and before working on system. |
Polarity Inspection | To ensure that (+) and (-) wires are not reversed | Volt-meter | No Problems | This test should spot problems upon initial commissioning and not need to be repeated for preventative maintenance inspections- still we do find strings wired in reverse polarity that were not caught in commissioning in which case the string fuse is burned. |
Combiner Box Test | Ensures fuses are OK and that current sums as intended. | Digital Multi-meter | Test usually entails shut down of system | While important in commissioning new system, not required for PM inspection as other tests can spot the common problems. |
String Open Circuit Voltage (Voc) | Check string is wired correctly inlcuding number of modules. | Volt-meter | Requires shut down of system and removal of fuse from fuse holder to create open circuit can damage aged fuse holders. | Measure operating voltage (Vmp) instead of Voc |
String Short Circuit Current (Isc) | test instrument with a short circuit current measurement function (e.g. a specialized PV tester) | Requires "Short Circuit Switch Box" to contain switching arc; requires fuse removal from fuse holder. | Measure operating current (Imp) instead of Isc | |
Functional Test | Ensure operation of switches, breakers, ground fault, arc fault, other functions. | Not applicable | Requires system shut-down. Aged equipment is likely to fail when exercised. | Some tests, such as inverter shutdown and restart, might be OK, but not recommended to exercise all functions for PM inspection |
Insulation Resistance Test | Ensure integrity of insulation on wiring. | Insulation Resistance Tester ("Megger") | Shock hazard; personnel protection; isolation of PV array from ground and from inverter and other equipment. High test voltages may damage devices (eg surge suppressors) or void warranties. | Usually not recommended for PM inspection of operating system- may be employed if wiring problems precipitate a need for it. |
IEC 62446 Category II tests | ||||
I-V Curve Test | Expose details of current/voltage characteristics | I-V Curve Tracer | Requires system shut-down and same issues as Voc and Isc test. | Not required for PM inspection- Vmp and Imp measurements will expose most problems. |
Infrared Scan Test | Identify PV modules or switchgear that is overheating due to improper operation. | Infrared Camera with good resolution | No Problems | Widely recommended in PM inspections. Can be used for PV modules, combiner boxes, connectors, batteries, and AC switchgear |
Other Tests | ||||
Voltage to Ground-Resistive Ground System | Verify resistance to ground for modules with resistive grounding with manufacturer's recommendation | Loop Impedance Meter | Only for modules with resistive grounding systems. Requires sytem stut down and isolation of modules. | Not generally recommended, but may be required by module manufacturer. |
Blocking diode test | Check polarity and voltage drop of diode | Diode Tester | Testing of bybass diodes in PV modules requires opening of junction box (potential leak) and requires module to be covered for measurement of bypass diode or may damage meter. | Not generally recommended, but may be conducted if module performance fails other tests. |
Wet insulation test | Identify faults that occur only in wet condition | Insulation Resistance Tester ("Megger") | Time consuming and expensive; inconsistent results. | Not generally recommended |
Shade evaluation | Measure shade of surrounding opbjects | Shading Profile Device (eg Solmetric Suneye) | No Problems | Not generally needed, but useful for establishing baseline and monitoring shade growth. |
Grid Interface Tests | Check operation of grid-protecting and anti-export features | Special equipment to "inject" voltage and frequency profile into device | Requires sytem shutdown; may require service shut-down. | Not recommended unless required by Grid Operator for typical PM inspection. |
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