FEM simulation of electrical stresses within motor stator windings for online PD Localization

Partial Discharges (PDs) within an AC motor may occur when local electrical stress exceeds the inception voltage. The phase of local electrical stress at each position in the motor varies with the three phase power supply, the PD activity at a location, therefore, varies with the voltage phase. In this research, the motor electric field model is calculated by a Finite Element Method (FEM) based simulation. The paper provides a theoretical foundation for the online PD localization methodology in motor stator windings, which forms also a basis for future work for an on-line motor insulation condition monitoring system to facilitate effective warning of imminent failure with added information of defect location.