How to find and repair ground faults in solar PV systems.

An article by Fluke.com/Renewable energy/Solar power. See link below. Here I read the entire article and present meticulously prepared diagrams and photographs to help you find and repair ground faults in a utility scale PV system. This procedure may help you find and repair ground faults in smaller, commercial or residential PV systems. This article also goes over the test results to expect from a normal PV string, and a ground faulted PV string. It goes over the current, voltage, and resistance tests used to locate ground faults. First some definitions. A PV array is the entire collection of PV strings including all modules that combine in a single combiner box. The module is the individual solar panel, and the string is the collection of modules connected in series within an array. A combiner box is the point where all strings of an array meet, and each negative wire home run is combined at a single negative bus bar. Same with the positive string home runs, they all combine in a positive busbar in the combiner box. An inverter is the device that all combiner boxes outgoing feeder cables go to. Many combiner boxes feed one central inverter, when the central inverter is used in the PV system. If a string inverter is used instead, strings go the string inverter, instead of the combiner box. Again, many strings may feed a string inverter. A ground fault, is an unintentional connection between a current carrying conductor and non-current grounded part of the system, such as racking, the inverter, or metal conduits. Grounded parts are generally metallic and can easily carry current. However, in a PV system, grounded parts are generally grounded to provide a path to ground in case of a lightning strike. When a current is transferred to a grounded part of a PV system, it may cause high currents, heating, and potentially a fire. For this PV systems have ground fault detection and interruption (GFDI) devices. Which detect and send a signal for the system to shut down, to prevent these mentioned hazards. This article tells you what ground faults are, types of ground faults, several techniques on how to find them, how to repair them. Voltage testing, insulation or resistance testing, live-dead-live, and other procedures are explained here too.
Source:
How to find and repair ground faults in solar PV systems | Fluke
https://www.fluke.com/en-us/learn/blog/renewable-energy/how-to-find-ground-faults-in-pv-systems?srsltid=AfmBOopcZtYrf3pgqD9byW_pgigVarF_ekkmBMAH3xcK1mJHFd4CDodl
Lockout Tagout procedure:
https://www.fluke.com/en-us/learn/blog/renewable-energy/solar-panel-safety-lockout-tagout
Keywords: solar, energy, renewable, ground fault, pv system, pv array, pv string, insulation test, voltage test, megger, ohm, meter, voltage, resistance, current, current test, live dead live, megohmmeter, voltmeter, ammeter, ohmmeter, intermittent ground fault, hard ground fault, residual current device, rcd, gfdi, ground fault detection interrupter.
Read and edited by Hector Vladimir, June 2025.Hector Vladimir 2025©
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