The method of the hot oil circulation are as follows:

1.Connect the oil storage tank to vacuum oil purifier machine and transformer oil pipeline. Transformer oil should be injected from the valve on the top of the body.

2.Connect the transformer and use a vacuum pump system to evacuate the pipeline.

3.After checking that the seal of the transformer is no problem, start the vacuum pump to evacuate.

4.Before oil filling, check that the transformer oil sample meets the oil quality requirements for oil filling and nitrogen discharge. The final oil level of the transformer should be more than 100mm above the upper edge of the iron core.

5.Connect the oil inlet pipe of the oil purification plant to the valve at the bottom of the transformer. The oil temperature at the outlet of the oil purifier machine should be between 50 and 70 °C. Start the oil purifier, first open the oil inlet valve on the side of the oil purifier, and use the vacuum pump of the oil purifier to evacuate the air in the oil inlet pipe, then open the valve at the bottom of the transformer to heat the transformer in circulation, when the temperature of the transformer body exceeds 20 ℃. Stop oil circulation heating.

6.When filling oil, inject dry air into the transformer through the valve on the top of the body to prevent moisture from entering.