In justifying the purchase of a spare 13.8 kV breaker for a 15kV metal-clad lineup I was asked a question about the failure modes of a medium voltage breaker. Our breakers are vacuum interrupter type. I've heard of catastrophic breaker failures happening, but the ones I'm most interested in...
We are looking at adding Hydran oil monitoring systems to our important transformers. Probably model 201R. From reading the literature, it only makes sense to monitor gases in the oil continuously, thereby determining if some overheating, arcing, or low magnitude fault is going on inside that...
In anticipation of doing some consulting in the near future I have applied for Professional Liability Insurance (PLI) but I don't expect a response for a week or two. Meanwhile I'm trying to estimate the cost for putting together my rates. I have a few questions for the forum.
1. Is it...
We have a 10/12.5MVA sealed transformer operating at 13.8 - 4.16kV and our recent oil tests gave "unacceptable" results for the power factor. The transformer consistently has a positive pressure nitrogen blanket on it, approximately 3-5 psig. I think it is very unlikely that water is...
Years ago I attended a Square D presentation where they sang the praises of cast coil or cast resin transformers. It was even stated that they have been successfully operated underwater in the ocean, showing how wonderful the insulation system is for wet or dirty environments. I know one...
I am planning to do a grounding review at one of our power plants (and maybe several others eventually) and I am doing research on ground testers to buy or rent. At this time I will be looking at connections and resistance of the grid to remote earth. I may do soil resistivity testing at some...
I am looking for anyone's personal experience with shutting down their transformers for the winter. We have some peaking power plants with multiple Generator Step-Up transformers and would like to shut down all but one GSU for the off-season (winter). Our GSUs have conservator tanks and are...
My previous work had all been involved with 161 kV and lower so I had little or no knowledge about corona. However we have recently had a substation installed at 345 kV and it sounds like a bacon frying party. Besides the annoyance, is this a problem?
The engineer designed it with a single...
