Question

A protection scheme for one of the main delta-star transformers at a zone substation features the following: differential protection; restricted carth fault protection; . Buchholz and gas impulse relays; phase overcurrent protection on both primary and secondary side; earth fault protection on the secondary side; and thermal overload protection Explain the specific role the above listed protection elements in terms of the nature of the fault and the need for back-up.

Answer 1

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