No matter what causes the trip of dry-type transformer, on the one hand, the load should be transferred as soon as possible and the operation mode should be changed. On the other hand, find out what kind of protection action. The submersible pump shall be stopped immediately to check whether the protection action is abnormal, whether the transformer is overloaded when tripping, and whether the transmission and feed lines trip at the same time. In addition to confirming that it is misoperation and can be switched on immediately, the insulation resistance shall be measured and judged according to the following conditions:
(1) If the insulation resistance and external conditions of the transformer are normal and the gas relay has no gas, the fault line (equipment) can be removed and the transformer can be restored;
(2) The main transformer is put into operation after the load is reduced due to overload;
(3) There is no sign that the protection has not been dropped, and there is no short circuit in the system. Check that all aspects are normal. At this time, check whether the relay protection secondary circuit and switch mechanism misoperate. If they misoperate, the transformer operation can be restored after eliminating the defects. If the cause can not be found out, the insulation resistance and DC resistance of the transformer should be measured to check whether there is free carbon in the transformer oil, and then the operation can be resumed according to the analysis. If any abnormal phenomenon is found in the transformer, it is forbidden to put the transformer into operation.
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