AC and DC partial discharge measurements on defective cables

HVDC links with extruded cables are being widely installed in power grids. Thus, methodologies for condition evaluation for HVDC extruded cable systems are required. Partial discharge (PD) measurement is widely adopted in cable commissioning tests under AC, while there is no availability of methodologies to test PD in cables under DC. Therefore, PD measurement techniques for artificially-defected cable models under DC stress are investigated in this paper, and obtained PD characteristics are compared with those under AC stress. It is concluded that the PD test under DC voltage could have a potential for condition evaluation/monitoring, once various problems related to their measurement on field would be solved.