Overload Of Oil Immersed Transformers

Transformers can operate under normal overload and accident overload conditions, and overload signals should be installed. Those who cannot install overload signals should have a comprehensive measuring instrument.
The overload signal value of oil immersed transformers should be 1.1 to 1.2 times the rated current of the transformer. The overload signal value of dry-type transformers should be 1.2 to 1.3 times the rated current of the transformer (based on the current of the fan during operation).
After the overload signal of the transformer is activated, attention should be paid to the changes in its load and temperature. If conditions permit, timely inspections should be conducted and the cause of the overload checked. If the overload is high (more than 1.3 times the rated current) or the temperature exceeds the upper limit, the load should be reduced.
When installing a comprehensive transformer, data should be downloaded monthly and the load should be analyzed. For transformers with an overload trend, the data download cycle should be shortened, and the transformer load and temperature should be measured during the calculation of the overload time. If conditions permit, timely inspection and inspection of the cause of overload should also be carried out. If the transformer load exceeds a high limit (1.3 times the rated current or above) or the temperature exceeds the upper limit, the load should be reduced.