Same 87T for 2 transformer not paralleled
Same 87T for 2 transformer not paralleled
(OP)
the transformer auxiliary service of a hydroelectric power plant 13.8/0.44kV-3.5MVA, Delta / star grounded was protected by a 87 as main protection. Later was added another transformer 13.8/13.8kV-6.5MVA, Delta / star grounded using the same 87.
13.8kV delta sides are connected at same source power.Star grounded sides are connected at separated loads. All CTs were appropriate ratio.
What would be the recommendations for 87 operate correctly?
13.8kV delta sides are connected at same source power.Star grounded sides are connected at separated loads. All CTs were appropriate ratio.
What would be the recommendations for 87 operate correctly?






RE: Same 87T for 2 transformer not paralleled
rasevskii
RE: Same 87T for 2 transformer not paralleled
I was worrying about inrush. I guess to energize transformers sequentially with a little delay. Will be this necessary?
RE: Same 87T for 2 transformer not paralleled
If yours is a numerical relay, the second energisation, ergo the inrush current that follows the second energisation should be restrained by the internal algorithm of the differential function block in the relay. So, even if you energise the two transformers sequentially, it shouldn't be a problem.