Power Transformer Transmission

A. Except for factory tests conducted by the manufacturer, new transformers should undergo on-site core inspection before installation and operation; The same applies after major repairs. (Short distance transportation may not be carried out when there are no bumps, but pressure resistance tests should be conducted.).
B. When the transformer is shut down for more than six months, the insulation resistance should be measured and an oil withstand voltage test should be conducted.
C. The transformer should undergo ≤ 5 full voltage closing impulse tests for the first time it is put into operation, and ≤ 3 times after major repairs. At the same time, it should run at no load for 24 hours without any abnormalities before gradually putting the load into operation; And keep records of all aspects. The purpose is to check whether the insulation strength of the transformer can withstand the rated voltage or operating overvoltage, and also to assess the mechanical strength of the transformer and the reliability of relay protection actions.
D. The insulation resistance of newly installed and overhauled transformers should not be lower than 70% of the manufacturer's test value at the same temperature.
E. To improve the utilization rate of transformers and reduce transformer losses, it is more reasonable to set the load current of transformers at 75-85% of the rated current.