Partial Discharge Characteristic of Different Defects at Generator Stator End-winding (CICED2022)

Abstract

Partial Discharge (PD) monitoring is one of the main methods to evaluate the insulation condition of generator stators to avoid insulation failure. Difference of PD characteristics of different defect types at the generator stator end-winding is be analyzed in this paper, which can provide a basis for PD pattern recognition. Three typical artificial defects were created on generator stator end-winding samples, including end-winding contamination, corona at the junction of the grading paint, and defect in slot exit. High voltage testing is carried out on these three defect models to obtain the PD phase characteristic maps of different kinds of defects at the stator end-winding. The results show that the PD characteristic of different types of defect show obvious differences, among which the discharge of end-winding contamination is the smallest, the PD characteristic pattern of defect at the junction of the grading paint is wing-shaped, the discharge amount of the slot exit defect is the largest, and the PD patterns show layered characteristics. By analyzing the characteristics of the Phase Resolved Partial Discharge (PRPD) patterns of three different defects, it is expected to serve as a basis for the PD pattern recognition at the stator end-winding and ensure the safe operation of the generator set.