Voltage Distribution of Steep Fronted Transients in Stator Windings–Modelling, Simulation and Experimental Verification

Abstract

Steep fronted surge voltages are produced at H.T. motor terminals due to various switching operations. These are distributed within the stator winding coils and turns of the phases in a highly non uniform manner leading to frequent insulation failures. There has been considerable interest in the development of the computational methods for analysing such phenomenon. This paper presents the development of a circuit model to predict the interturn voltage distribution and its validation through comparison of the results of simulation using EMTP with those obtained experimentally on sample coils for a specific three phase 6.6kV, 400KW H.T. motor. The correlation between the experimental and simulation results is found to be good.