Locating partial discharge in insulation of high voltage electric machines using circuit-field model analysis

This paper uses circuit and field models incorporated into the finite element analysis to detect and locate partial discharges (PDs) in winding insulation of high voltage electric machines. Locating PDs with KHz-MHz frequency components is enabled by fast transient models. For this purpose, a PD current pulse with MHz frequency component is injected into each winding turn of the very fast transient model of a squirrel cage induction machine 6KV/250KW. To detect the PD pulse, all field and circuit equations are presented and solved to obtain the system final matrix. In addition, to investigate the model accuracy, the induction machine windings are also simulated using the multi conductor transmission line circuit model. After injecting the PD pulse, the discharge locations are estimated using current analysis. The results are then compared with the proposed model, confirming the reasonable accuracy of the model in estimating the location of PD with high frequency components.