Partial discharges development in a void and its effect on the material surface

Partial Discharge detection and interpretation is one of the most useful diagnostic tools for quality assurance testing during the design, manufacture and life assessment of electrical equipment. In order to assess the aging of insulation materials which is subject to partial discharges, it is necessary to investigate and understand the PDs activities which occur in voids in the insulation and their reaction with the surface of the void in insulation. In this paper a wide band measurement system was used to detect the individual PD pulse signals to reveal the development of PDs in the time-domain. The photon emission was also observed by using a pulsed photomultiplier. The damaging effect of the PD is shown by surface microscopy and leakage current measurement