Study on the Partial Surface Discharge Process of Oil-Paper Insulated Transformer Bushing with Defective Condenser Layer

Oil-impregnated paper condenser transformer bushings are an important part of equipment, and partial discharge (PD) occurred when defects exist on the aluminum foil layers. Firstly, to study PD process oil-paper insulated capacitance graded bushing with defect broken foil, a defective sample is constructed parameters capacitance, carbonization traces at different voltage levels. Then, in order verify layer space charge variation insulation system model, surface flashovers needle-plane model based bipolar transport hydrodynamic was built. The simulation, by Transport Diluted Species physics COMSOL Multiphysics software, points out electrode caused action electric field distortion under voltages. results simulation experiments showed that mainly divided into three stages: tip corona discharge, streamer oil, flashovers. amplitude larger more electrical branches discharged shorter time is. findings article have implications for inside bushing.