Auxiliary Transformer

Description

Auxiliary transformers supply power to a generating plant’s auxiliary loads (think feed pumps, coolant pumps, and safety devices that a power plant needs to run). There are a few different types of auxiliary transformers to keep track of, but fortunately, we have more acronyms to make our life easier. A unit auxiliary transformers (UAT) is connected to the same bus as the generator, stepping down voltage to feed the auxiliary power system busses. Whenever the generator is running, the UAT is supplying the auxiliary load.

The reserve auxiliary transformer (RAT) or start-up auxiliary transformer (SAT) are backup transformers which are connected to an offsite high voltage system – supplying the plant auxiliary power during startups or outage periods. All auxiliary transformers are relatively critical to a plant’s safe operation, so you don’t want to see problems with these, or you may be facing a possible plant shut down. Not good.

Well, we’ve unfortunately run out of time today, but we still have a bunch of transformers to cover. So, make sure you come back next week to find out which ones we left out. You won’t regret it. In the meantime, check out this Guide to Transformer Ratio Measurements, if you’re ready to get serious about your transformer testing program.