Partial Discharge Modeling of Internal Discharge in Electrical Machine Stator Winding*

Rotating machine is one of the critical elements of the power systems whose reliability is improved with proper condition assessment and fault detection techniques. Partial discharge (PD) identification is essential for the assessment of insulations particularly for medium and high power units operating at higher voltage levels. This paper proposes a finite element based model that illustrates the PD behavior in the electric machine stator winding. It also computes the PD features from the defects similar to the characteristics obtained by commercial detection systems. The proposed finite element analysis based computational model utilizes multiphysics which includes electrodynamics and thermal boundary conditions. This model describes complete variation in properties of defects and insulation of the stator winding under various operating stresses. The simulated PD features that include charge magnitude and PD occurrence are comparable with commercially available solutions. This model illustrates the level of deterioration in the winding insulation, whose characterization is used for defects classification.