Transformer differential protection trip after checking and processing

1 Check the transformer body without exception, check the differential protection within the scope of porcelain whether flashover, damage, leads for short. (2) If the transformer  mcb circuit breaker  protection device within no obvious fault, you should check relay and the secondary circuit is faulty, whether the DC circuit
There are two ground. 3 After electric transformer  the above without exception, should be removed immediately after the load test feeding time, and then try to send the trip, not sending. 4 relay or if it is due to the secondary circuit failure, the DC  circuit breakers  points caused malfunction, differential protection should be out of operation, the transformer power transmission Before dealing with the secondary circuit faults and DC ground. 5 Differential Protection and heavy gas protection while operating the transformer trips, without internal inspection and testing without the transformer into operation.