Example: Location of the ground fault
The example shows a ground fault between the second and third PV module.
Checking the PV System for Ground Faults
Qualified person
DANGER
Danger to life due to electric shock in case of a ground fault
If a ground fault occurs, parts of the system may still be live. Touching live parts and cables results in death or lethal injuries due to electric shock.
- Disconnect the product from voltage sources and make sure it cannot be reconnected before working on the device.
- Touch the cables of the PV array on the insulation only.
- Do not touch any parts of the substructure or frame of the PV array.
- Do not connect PV strings with ground faults to the inverter.
- Ensure that no voltage is present and wait five minutes before touching any parts of the PV system or the product.
NOTICE
Destruction of the measuring device due to overvoltage
- Only use measuring devices with a DC input voltage range of 1000 V or higher.
Proceed as follows to check each string in the PV system for ground faults.
Procedure:
- Disconnect the inverter from all voltage sources ( > Disconnecting the Inverter from Voltage Sources).
- Measure the voltages:
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Measure the voltage between the positive terminal and the ground potential (PE).
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Measure the voltage between the negative terminal and the ground potential (PE).
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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.
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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.
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If there is no ground fault and the message is still displayed, contact the Service.
- Recommission the inverter ( > Recommissioning the Inverter).
DANGER
Danger to life due to high voltages