Grounding for a spare transformer
Grounding for a spare transformer
(OP)
We are procuring a 607MVA transformer (345 KV to 22 KV) which we are storing as spare. As for the grounding requirements, while the transformer stays de-energized as spare, we were provided with three #4 gauge wires. We want to know if there is a spec (IEEE or ANSI) on such requirements particularly for Transformers that stay deenergized, except for the cooling bank that might be operational every 6 months through 480V circuit for routine checks. If any case would #4 gauge (3 phase) wire be adequate?






RE: Grounding for a spare transformer
If its the former, I'd size the grounding for operations. Its one less thing to worry about come the panic when the primary unit goes T.U. and people are scrambling around getting it hooked up. Someone may see temporary grounds and assume they are OK for operation.
If this unit will have to me moved, ground to suit the 480V system and to ensure poper lightning protection. I'm assuming that LAs will be installed (or grounds) on bushings to protect the stored unit so as not to discover damage only after dragging the spare out in an emergency.
RE: Grounding for a spare transformer
Bill
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"Why not the best?"
Jimmy Carter
RE: Grounding for a spare transformer
I am more worried about the size of the wires for grounding to protect the transformer from lightning. This transformer will be stored as a Spare until we have a need to use it. That means it will remain in the storing pad for years, without any lightning arrestors or anything else. What should be the size of the wire to protect a deenergized transformer from lightning?
RE: Grounding for a spare transformer
RE: Grounding for a spare transformer
That is: for long-term outdoor storage, wouldn't you have to ground the frame or casing itself, the input power leads, and the output power leads?