Depending on the inspection request, we look for the most common problem points. Assuming plans were followed correctly, materials are at or above specification, and no eminent dangers are found, these are usually the top points of failure we find during inspection.
1. Ground faults from field-installed connectors
- Use the correct crimping tool, per the manufacturer. Some crimping tools require calibration or limit the number of crimps per dye.
- Ensure housing and gaskets are firmly seated around insulation. Verify that the string wire connector housing is sized properly for conductor insulation diameter.
- Avoid securing field connectors at a local low point in a wire run as this can cause water to hug the wire and lead toward connectors.
- Install connectors at the top or sides of module frames. Installing connectors at the bottom of the frame where water collects is unsafe.
- Secure both sides of each connector to prevent expansion stress.
2. False or nuisance data acquisition system communication failures
- Ensure notifications are properly set, including the threshold of upload attempts to prevent nuisance communication failure alarms.
- Ensure all components are installed correctly, as intermittent failures can be caused by loose connections or faulty wiring.
- Dedicate a circuit breaker to supply power to devices. It’s easy to unplug communication devices if power is supplied through a wall outlet.
- Have a clear protocol for the building’s IT personnel. Replacing a router will cause a disruption or failure for the distributed antenna system (DAS) system.
- On remote sites using cellular models, make sure there is a plan administrator who will remember to pay the bill!
3. Low or no open circuit string voltage
- Verify all connectors are terminated properly. Ensure any field-installed module-to-module jumpers are installed properly.
- Avoid wire chaffing and ground faults by practicing appropriate wire management within the racking system. Inspect for pinched wires and wire insulation exposed to metal edges.
- Inspect module bypass diodes visually or with a thermal imaging camera.
- Utilize a string-level tester with insulation testing capabilities. This will give you vitals like Voc, Isc, Vmax and Imax and can test insulation at 500 V to 1,000 V.
4. Low current short circuit or operating current on strings
- Inspect for module soiling.
- Verify all connectors are tight and making good contact. Current can pass through poor connections.
5. Inverter fault codes
- Do not power cycle an inverter if a problem occurs. Although power cycling can solve some inverter issues, it will not correctly identify the cause.
- Log inverter fault codes and consult the operations’ manual. Call the manufacturer’s technical support, if needed. These people can often teach you how to be better at finding and resolving field issues.
Being great at problem solving starts with 50% skill and 50% intuition. I quite often start with a hypothesis: What will I find during this experiment? I make my observations and then try to prove myself wrong. If I cannot prove myself wrong, then I have a conclusion.