Slot Partial Discharge Characteristics Under Electrothermal Aging of 10 kV Motor Stator Windings

Electrical and thermal stresses have an important role in the process of slot partial discharges (PDs) for 10 kV motor stator windings. In this paper, an accelerated electrothermal aging system has been carried out to conduct the research of the slot discharge characteristics in 10 kV stator windings, such as slot PD patterns, the NQS and the changes of the insulation surface and stator core surface at the end of aging. During the experiment, at triple the rated line-to-ground voltage of 6 kV, two groups of windings were aged for 30 days under different temperatures. The result confirms that electro-thermal aging can promote the slot discharge to a certain extent and lead to the surface degradation. In addition, the study can provide a judging basis for on-line monitoring and fault diagnosis of HV motors because all of the PD patterns are collected under rated voltage.