Arcing Ground Faults

[Gibbs]

I have a 3 phase, 4-wire, 120/240 volt delta service to a machine shop. I have recently had some 3 phase equipemnt damaged: an inverter, transformer, and 2 three phase surge protectors damaged from high voltage. There was no damage to any single phase equipment. I suspect an arcing ground fault. Any information on this subject and references would be appreciated. Also any suggestions on how to locate the point of fault.

 

[jbartos]

Suggestion: A ground fault transformer with the high-resistance grounded neutral, the ground fault monitoring and possibly trip.
References:
1. D. Beeman "Industrial Power Systems Handbook," McGraw-Hill Book, Co., 1955
2. ANSI/IEEE Std 242-1986 Chapter 7 "Ground Fault Protection"