Reduction Method of Fluctuation in Partial Discharge Inception Voltage for Inverter‐Fed Rectangular Wire Motors

We investigated the decisive factors that affect partial discharge inception voltage (PDIV) fluctuation between the coil wires under a sinusoidal voltage by using a rectangular wire motor. As a result, we found that PDIV under low humidity fluctuates by the surface charge, and PDIV under high humidity varies transitionally with the surface conductivity activated by predischarge. From these analyses, we proposed the measurement method of PDIV with a low fluctuation and transition for the rectangular wire motors, which will be optimized by environmental humidity, predischarge condition, and measuring frequency.