PDA

View Full Version : Transformer bank grounding?



nanuuk
05-05-2011, 03:26 PM
I have a bank of 3 transformers 500kva on a delta system that some one has cut all the earth grounding off of the transformers and the pen fencing. What problems/dangers am i looking at if this does not get rectified. What is the proper way to ground this equipment/fencing?

frank
05-05-2011, 07:42 PM
I think that you should aim your question to an electrical forum.....this is far outside of the knowledge of a Refrigeration Forum.

Personally though, I would consider that you should just go ahead and replace the cut off earth groundng wires....

Seems like the copper thieves are not restricted to the UK then...:D

Magoo
06-05-2011, 06:36 AM
That will create a huge fault rating if a coil in trani fails. But is the the grounding peg still in place. I would be asking the local power supply authority to check /repair. High voltage side fault rating would be disasterous, like large explosion and fire from the oil.

SeanB
08-05-2011, 02:17 PM
If you replace the cabling try to get a theft resistant cable, it has a few cores make from copper coated high carbon steel wire. Hard to handle, hard to bend, really hard to cut without a grinder, but no scrapyard will take it unless the steel is removed as it will break the cutters. Other method is to use a steel cable that is a lot thicker as a replacement, it has a lot lower scrap value, and is harder to cut. The railways have a big problem with this, and weld steel cable to the rails as jumpers instead of copper that kept getting stolen. Only problem is that to replace a 16mm2 cable you have to use a minimum of 25mm2 steel cable, which is a lot bigger, and has a higher resistance per unit length, so is only good over under a 10m or so length. As a bonus you can weld it to a steel plate and use that as a connection to the cable instead of a crimped connector.