How to replenish oil for oil-immersed transformer oil leakage?

When the transformer in operation is short of oil, when filling the transformer oil, it should be operated according to the relevant technical requirements and regulations:
1. Deactivate the transformer in operation, and take safety measures such as power off and lock;
2. The transformer oil used must meet the standard, and the quality assurance certificate should be checked;
3. The electrical test report should be checked;
4. After refueling, let it stand for a period of time before putting it into operation, and observe it for a period of time after it is put into operation.
Regarding the oil mixing problem of transformer oil, the national standard GB/T14542-2017 shall prevail, and the excerpts are as follows:
1. When oil products need to be mixed for use, the oil products involved in mixing should meet their respective quality standards (new oil should meet new oil quality standards, and operating oil should meet operating oil quality standards).
2 When the electrical equipment is insufficiently filled with oil and needs to be replenished, the same oil base, the same brand and the same additive type should be added. The unused transformer oil that meets the GB2536 standard or the used transformer oil that meets the GB/T7595 operating oil quality standard should be selected, and the characteristics of the supplementary oil should not be lower than the oil in the equipment. When the oil replenishment amount is large (greater than 5%), the sludge precipitation test of the mixed oil should be done before the oil replenishment to confirm that there is no sludge precipitation, the acid value and the dielectric loss factor are lower than the oil in the equipment, and then the oil replenishment can be carried out.
3 Oils with different oil bases, brands and additive types should not be mixed in principle. Under special circumstances, if new oils of different grades need to be mixed for use, the actual pour point of the mixed oil (the pour point should refer to the pour point index of new transformer oil in GB2536) should be determined whether it is suitable for use in the area, and then press DL/ Method T429.6 conducts the open cup aging test. After aging, the mixed oil should have no sludge precipitation, and the acid value and dielectric loss factor of the mixed oil should not be worse than the worst single oil sample.
4 If new oil of different grades or used oil is mixed into the operating oil, in addition to the pour point of the mixed oil should be determined in advance (the pour point should refer to the pour point index of the new transformer oil in GB2536), the following requirements should also be met:
a) The various characteristic indexes of the supplementary oil should not be lower than that of the oil in the equipment, and the quality of the mixed oil should not be lower than that of the running oil;
b) The open cup aging test shall be carried out for the operating oil, supplementary oil and mixed oil according to the method of DL/T429.6. After aging, the mixed oil shall be free of sludge precipitation, and the acid value and dielectric loss factor of the mixed oil and supplementary oil shall not be greater than that of the operating oil. Measurement results after oil aging.
5. When carrying out the mixed oil test, the mixing ratio of the oil sample should be the same as the ratio actually used; if the mixed oil ratio cannot be determined, use a 1:1 mass ratio for the test.
What is the role of transformer oil?
Transformer oil is a flowing liquid, which can fill the air gap between the components in the oil tank, remove the air, and prevent the insulation strength from being reduced due to the damping of the components. The dielectric strength of transformer oil itself is greater than that of air, so after the oil tank is filled with oil, the dielectric strength of the transformer can be improved. Transformer oil can also keep the original physical and chemical properties of wood and insulation, and has anti-corrosion effect on metal, so that the insulation of the transformer can be kept in good condition. In addition, the transformer oil can also absorb the heat generated by the winding and the iron core during operation, and play a role in cooling. Therefore, the role of transformer oil is insulation and cooling. Commonly used transformer oil is divided into domestic No. 25, No. 45 and No. 10 three.