SMA SB 1300TL Service Manual - Manual (Page 17)

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 sections below.
• 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 to life due to high voltages
• Disconnect the inverter from all voltage sources (see Section 2.2, page 7).
2. Measure the voltages:
• Measure the voltages between the positive terminal and the ground potential (PE).
• Measure the voltage between the negative terminal and the ground potential (PE).
• Measure the voltages 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.
Example: Location of the ground fault
The example shows a ground fault between the second and third PV module.
4 Troubleshooting SMA Solar Technology AG
Service Manual 17 SB13-21TL-SG-en-11