Advanced Monitoring Technique for Leakage Current and Partial Discharge in Inverter-Fed Motor Insulation

The increasing use of Inverter-Fed Motors (IFMs) in industrial, traction, and power applications has significantly changed the electrical stress conditions experienced by motor insulation systems. Pulse-width modulated (PWM) inverter supplies generate fast voltage transients with high dv/dt, repetitive switching events, and voltage reflections, resulting in increased leakage currents and Partial Discharge (PD) activity. These effects accelerate insulation degradation and can lead to sudden motor failures. Conventional leakage current and PD measurement techniques, developed for sinusoidal excitation, are often ineffective in IFM environments due to limited bandwidth, high-frequency noise, and the need for direct access to high-voltage terminals. This paper presents a novel, non-intrusive…