Propagation mode and speed of partial discharge pulse through the stator windings of turbine generator

For online insulation monitoring of turbine generators, it is an important problem to describe the partial discharge (PD) pulse propagation process in stator windings. According to the frequency characteristics of PD and winding structure properties, the paper expounds that PD pulse travelling mode in slot and end windings is a quasi-TEM mode, so the multi-conductor transmission line model is feasible in analyzing PD propagation characteristics. Based on the simulation and test results, the paper discusses the occurrence of fast and slow components in PD waveform propagation. The coupling effects existing between upper and lower bar in the same slot, and among end windings are the causes of fast component. In this paper the traveling speeds of PD pulses and the relation between the speeds and the parameters of turbine generator are investigated. The test and simulation results are shown taking the effects of laminated core into account