Analysis of partial discharge pulse propagation along generator stator windings

A generator stator winding consists of a number of stator bars and overhang connections. Due to the complicated winding structure and the steel core, the attenuation and distortion of a partial discharge (PD) pulse transmitted through the winding are complicated and have the nature of frequency-dependence. This paper gives an explanation of PD pulse propagation phenomenon in the winding through theoretical analysis on different models and experimental investigations on a number of generators. A low impulse voltage method and associated digital analysis techniques have been developed to determine the frequency characteristics of travelling waves in the winding.