Check the PV system for ground faults by measuring the voltage
Qualified person
Proceed as follows to check each string in the PV system for ground faults.
Procedure:
- Disconnect the inverter from all voltage sources.
- Measure the voltage between the positive terminal and the ground potential (PE).
- Measure the voltage between the negative terminal and the ground potential (PE).
- Measure the voltage between the positive and negative terminals.
- If the following results are present at the same time, there is a ground fault in the PV system:
- All measured voltages are stable.
- The sum of the two voltages to ground potential is approximately equal to the voltage between the positive and negative terminals.
- If a ground fault is present, determine the location of the ground fault via the ratio of the two measured voltages and eliminate the ground fault.
- If a definite ground fault cannot be measured and the message is still displayed, measure the insulation resistance
- Reconnect the strings without ground faults to the inverter and recommission the inverter (see inverter installation inverter).
DANGER
Danger to life due to high voltages
| Location of the ground fault |
The example shows a ground fault between the second and third PV module.
