SMA STP 50-40 - 11.4 Checking the PV System for Ground Faults

11 Troubleshooting
SMA Solar Technology AG
Operating manualSTP50-4x-BE-en-23112
11.4 Checking the PV System for Ground Faults
If the red LED is glowing and the event number 3501, 3601 or 3701 is being displayed in the
Results menu on the inverter user interface, there may be a ground fault present. The electrical
insulation from the PV system to ground is defective or insufficient.
DANGER
Danger to life due to electric shock when touching live system components 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 ensure it cannot be reconnected before
working on the device.
• Only touch the cables of the PV modules on their insulation.
• 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.
WARNING
Danger to life due to electric shock from destruction of the measuring device
due to overvoltage
Overvoltage can damage a measuring device and result in voltage being present in the
enclosure of the measuring device. Touching the live enclosure of the measuring device results in
death or lethal injuries due to electric shock.
• Only use measuring devices with a DC input voltage range of 1000V or higher.
Procedure:
In order to check the PV system for ground faults, perform the following actions in the prescribed
order. The exact procedure is described in the following sections.
• Check the PV system for ground faults by measuring the voltage.
• If the voltage measurement was not successful, check the PV system via insulation resistance
measurement for ground faults.
Test by Measuring the Voltage
Proceed as follows to check each string in the PV system for ground faults.
Procedure:
1.
DANGER
Danger to life due to high voltages
• Disconnect the inverter from all voltage sources (see Section9, page91).
2. Measure the voltage between the positive terminal and the ground potential (PE).