Main transformer differential protection action and treatment - News - Global IC Trade Starts Here Free Join

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The main transformer differential protection action trip is due to:
(1) A short circuit fault has occurred in the main transformer and its bushing lead-out line.
(2) Protect the secondary line from malfunction.
(3) The current transformer is shorted or open.
(4) Internal fault of the main transformer.
The principle of processing is:
(1) Check the external bushings and leads of the main transformer for faults and abnormalities.
(2) If the abnormality is not found after the inspection in item (1), but the station has a DC unstable grounding hazard or has been operated with DC grounding, consider whether there is a DC two-point earthing fault. If so, the short-circuit point should be eliminated in time and the transformer should be re-powered.
(3) If the inspection of item (2) is carried out, no DC ground fault is found, but there is voltage at both ends of the outlet intermediate relay coil, and the grounding of the differential relay has returned, it may be the differential trip circuit and the protection secondary line short circuit. As a result, the short-circuit point should be eliminated in time, and then the power is sent.
(4) Check whether the high and low voltage current transformers have open circuit or poor terminal contact, find the problem in time, and then resume power transmission to the transformer.
(5) If the above check does not find any fault or abnormality, it can be judged as the internal fault of the transformer, stop the operation, wait for the test, if it is the lead line fault, replace the lead wire in time.
(6) If the differential protection and the gas protection trip at the same time, it should first be judged as the internal fault of the transformer and treated according to the heavy gas protection action.