SMA SUNNY BOY 3000TL Single Tracker, Service Manual

5

Checking the PV System for Ground Faults

If the inverter displays the event numbers 

3501

, 

3601

 or 

3701

, there could be a ground fault. The

electrical insulation from the PV system to ground is defective or insufficient.

Danger to life due to electric shock

In the event of a ground fault, high voltages can be present.

• 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.

Destruction of the measuring device due to overvoltage

• Only use measuring devices with a DC input voltage range of 1,000 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 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 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.

5 Checking the PV System for Ground Faults

SMA Solar Technology AG

Service Manual

19

SB30-60TL-21-SG-en-11