Fundamental Difference of Partial Discharge Phenomena under AC and DC Stresses

The destructive characteristics of partial discharges (PD) to insulation material are well known. PD in AC and DC stress has different behavior and characteristics. In the case of AC stress, phase-resolved partial discharge (PRPD) patterns, can be used for detection and evaluation of characteristic discharge parameters. However, for DC stress, no phase information is available. In this contribution the differences between AC and DC stresses and the influence of the temperature under DC stress by using analytical investigation and simulation results are discussed in order to achieve a better understanding about PD at DC stress Furthermore, by performing different experiments various effective parameters of PD activity at both AC and DC stress have been investigated.