Why and when does a surge arrester's operation can be seen as a Ground-Fault by a protective device?

[sgayam]

I am trying to understand if ever a Surge arrester operates and that is seen as a ground-fault condition by a relay or any other protective device on the system.

If not, why and how? Can someone provide a technical reference/paper that determines this condition.

Please assume a MV Subststation and the arrester is installed at the incoming line to protect the transformer. Let me know if you have any other questions to clarify this question.

Thank you.

 

[Jraef]

No documentation, but in general when a surge arrester “operates”, that means the incoming voltage has exceeded the threshold voltage of the SPD and it safely conducts that energy to ground. So to any GFP device upstream of that SPD, that current flow to ground will be current not returning in another leg, so it would be no different than a ground fault. How MUCH current flows through that SPD would be the thing that might allow the GFP device to hold or not, depending on settings and system configuration.

Keep in mind that the entire issue is that this would only take place if there was a SURGE on the line that may have caused damage and ultimately a real ground fault anyway. So if your GFPD tripped due to the SPD doing its job, that’s not necessarily a bad thing.

 

[GoldDigger]

RF and noise filters and surge snubbers, on the other hand, when connected from an ungrounded line to ground/EGC can constantly draw capacitive current. If there are a large number of such filters on a circuit, they might draw enough current to trip a branch GFCI.