Influence of repeated impulse voltage application on partial discharge inception voltage in insulating material - Air gap composite system

Inverter driving motors became more popular from the viewpoint of efficiency and controllability. In addition, demands for improving performance of the motors are also increasing such as high output or miniaturization. From these demands, electrical insulating materials in motors are expected to subject higher electric field. Partial discharge easily occurs with exposing higher field, and it can lead to dielectric degradation and finally breakdown by spark discharge. However, the discharge characteristics under surge voltage application has not been clarified in detail. In this paper, it was investigated the air gap dependence of partial discharge inception voltage under repeated impulse voltage application (Imp-PDIV) in metal-air gap-metal system. In addition, it was showed the probability of Imp-PDIV estimation in insulating material-air gap-insulating material system simulating twisted pair. © 2019 The Institute of Electrical Engineers of Japan.