1. Preparations

Drain the oil in the oil pillow first, continue to put the oil in the body, and follow up with dry air or nitrogen while draining the oil to prevent the transformer insulation from getting damp. Stop draining the oil when the oil is about 100 mm into the dome of the press. Take the oil sample of the body for the dielectric loss factor test, which is used as the reference value before Transformer Oil Treatment.

 2. Heating Oil Purifier

Connect the pipelines according to the conventional vacuum Transformer Oil Purifier, turn on the vacuum oil purifier machine. When the transformer oil is heated and filtered, the temperature at the outlet of the oil purifier is required to be controlled at 60-65°C, and the outlet temperature of the Oil Purifier, the temperature of the body, and the pressure value of the filter are recorded every two hours. When the filter pressure is too large, the filter should be replaced. When the temperature of the body reaches about 50°C (the purpose is to bring out the high dielectric loss substances that stick to the body), turn on all submersible pumps and run for 0.5 hours, then turn off the submersible pumps (note that when the submersible pump is turned on, do not turn on the cooler fan), continue to heat and filter the oil for 8 hours, take the oil sample for the dielectric loss factor test, and record it. Then pump all the oil in the transformer into the oil tank. Note that when pumping oil, the transformer body is injected with dry air or nitrogen at the same time. After all the oil in the body is pumped, the pressure of the dry air or nitrogen in the transformer body is required to be kept at 0. 02 MPa or so.

3. Transformer Oil Treatment for dielectric loss

Thoroughly re-treat all the connecting pipes with new oil before the oil dielectric loss treatment, and connect all the pipes as shown. In the oil storage tank, the oil temperature is heated to about 65 ℃ through the oil dielectric loss treatment tank and filter, and the oil sample is taken every 4 hours for the dielectric loss factor test. When the dielectric loss value is reduced to the ideal value, the cycle continues for 4 hours. Sampling and testing medium loss factor value, moisture, dielectric strength. Finish the oil dielectric loss treatment, and start preparing to inject oil into transformer.

4. Oil Filling by Transformer Oil Purifier

   The oil filling of the transformer should be carried out after the vacuum degree reaches the requirements. The transformer oil should be injected from the oil discharge valve at the bottom of the main body. The oil temperature is higher than the temperature of the transformer core, and the oil filling speed of transformer oil purifier should be controlled below 100L/min. stop oiling. The required vacuum degree should always be maintained during the Transformer Oil Filling Treatment, and the vacuum should be continued after the oil filling is stopped.