Detection and evaluation of partial discharges (PD) is important for quality assurance and diagnosis of electrical insulation systems. With increasing use of DC voltages in electrical transmission and distribution systems, the field of PD under DC voltage stress needs to be further investigated.
CIGRE Working Group D1.63 was approved for start in May 2015, where available knowledge and experience in particular concerning the field distribution in insulation systems used in DC voltage systems, and the physical processes of the PD phenomena under DC voltage stress should be reviewed. In order of guiding to meaningful procedures for DC PD measurements of HV equipment thorough understanding of i) the differences of PD behaviour between AC and DC with respect to the physical process and ii) influencing factors of operating conditions (as e.g. polarization, temperature etc.) of different insulation systems under DC stress and respective effects on PD phenomena had to be examined.