Checking The Functioning Of The Varistors - SMA SUNNY MINI CENTRAL 6000TL Installation Manual

SMA Solar Technology AG
The approximate position of the ground fault can be determined from the ratio of the measured
voltages between plus against ground potential and minus against ground potential.
Example:
The ground fault is between the second and third module in this case.
3. Repeat step 2 for each string.
Result
☑ You have found a ground fault.
☑ You have found no ground fault. It is likely that one of the thermally monitored varistors is
☑ The ground fault check is finished.
9.3.2 Checking the Functioning of the Varistors
Varistors are wearing parts. Their functional efficiency diminishes with age or following repeated
responses as a result of overvoltages. It is therefore possible that one of the thermally monitored
varistors has lost its protective function.
Installation Guide
Action
• The installer of the PV generator must remedy the
ground fault in the affected string before you may
reconnect the string to the inverter.
• Do not reconnect the faulty string.
• Restart the inverter as described in section
7.3 "Closing the Inverter" (page 55), but without
reconnecting the faulty string.
defective.
• Check the varistors as described in section
9.3.2 "Checking the Functioning of the Varistors"
(page 69).
Failure Search
SMC6-8TL-IEN101040 69