ZL Series Transformer Insulating Oil Vacuum Filtration Machine

ZL Series Transformer Insulating Oil Vacuum Filtration Machine

This unit employs vacuum drying principles, separation engineering, precise filtration technology, and multiple technical innovations to produce a device for rapid purification and processing of various insulating oils. It is suitable for power plants, power stations, electric power companies, substation industries, metallurgy, petrochemical, and mechanical industries, especially for on-site maintenance of transformers in large substation stations above 110KV and for deep purification of various insulating oils such as high-voltage transformers, current transformers, capacitors, circuit breakers, and oil switches. It can also be used for vacuum oil injection and drying in transformers. It is capable of on-site live-line operations.

ZL Series Transformer Insulating Oil Vacuum Filtration Machine

Procedure and process requirements for transformer oil's dielectric loss reduction:

1. Preparatory Work

Drain all the oil from the oil pillow first, then continue to drain the main transformer oil. While draining, follow with dry air or nitrogen to prevent the transformer insulation from becoming damp. Stop draining the oil when it reaches approximately 100 mm from the transformer's arch. Take a sample of the main oil for a dielectric loss factor test, which will serve as the baseline before the transformer oil treatment.

2. Heating Filter Cartridge

Connect the pipeline according to the conventional transformer vacuum oil filtration process and start the vacuum oil filter. During the heating and filtering of transformer oil, maintain the outlet temperature of the filter at 60-65°C. Record the outlet temperature, body temperature, and filter pressure every two hours. Replace the filter element when the filter pressure is too high. When the body temperature reaches about 50°C (to remove high dielectric loss substances adhering to the transformer body), run all the submersible pumps for 0.5 hours after which turn them off (note: do not start the cooler fan when the submersible pumps are running). Then, continue heating the filtered oil for 8 hours, take oil samples for dielectric loss factor testing, and record the results. Next, pump all the oil from the transformer into the oil tank, ensuring that the transformer body is simultaneously filled with dry air or nitrogen during the pumping process. After all the oil in the transformer body is pumped out, maintain the pressure of dry air or nitrogen inside the transformer body at approximately 0.02 MPa.

3. Oil Interference Treatment

Before oil interfacial treatment, reprocess all connecting pipelines with new oil* by grounding, and connect all pipelines as shown in Figure 2. In the storage tank, heat the oil to approximately 65℃ by circulating through the oil interfacial treatment tank and filter. Take oil samples every 4 hours for dielectric loss factor tests. Continue circulating for 4 more hours after the interfacial loss value drops to the ideal level, then test the dielectric loss factor, trace water, and oil electrical strength. Complete the oil interfacial treatment and begin preparing to inject oil into the main body.

4. Body lubrication

The oil filling of the main body should be conducted after the vacuum level meets the requirements. Transformer oil should be filled through the oil drain valve at the bottom of the main body. The oil temperature should be higher than the transformer core temperature. The filling rate should be controlled below 100L/min. Stop filling when the oil level is approximately 100-150mm from the top of the transformer tank. Maintain the required vacuum level throughout the filling process. After stopping the filling, continue to evacuate the vacuum for 2 hours for a 110kV main transformer and 4 hours for a 220kV main transformer, then break the vacuum when the weather is favorable.