Development of Circulative Reactor Used for Purification of Contaminated Transformer Oil with DC-steep Pulse Electric Field

We developed a circulative reactor as a part of DC-steep pulse electric field generator to purify contaminated or aged transformer oil. Firstly, we established a model of impurity particle involved in transformer oil to analyze the force condition on the particles under DC and pulsed electric fields. Then, we simulated the electric field distribution of plate-plate shape reactor and wire-tube shape reactor by using the Ansoft Maxwell to select a better geometric shape for the reactor. Finally, we designed, built up, and tested the reactor taking into account some electrical and mechanical factors such as circulatory mode, distance between electrodes, materials, etc. The force condition analysis show that the superposed DC-steep pulse electric field with high intensity and large electric field gradient is effective in purifying contaminated transformer oil. The simulation of electric field distribution suggests that the plate-plate shape reactor with impurity collecting body is suitable for transformer oil purification. According to the performance test, the reactor meets all the design requirements, and its insulation can withstand electric field of superposed 20 kV DC and 10 kV impulse, which is fully capable for future purification experiments.