Classification of defects in solid insulation material by PD methods

Solid insulators have good insulation properties. However when they have voids or cracks in the bulk or at the surface, the electric field is concentrated and the insulation material is degraded at this point. Defects in a solid insulation system act as a source of partial discharge (PD). PD is very harmful since it often leads to deterioration of insulation by the combined action of the discharge ions bombarding the surface and the action of chemical compounds that are formed by the discharge. PD can indicate incipient failure, so it has been used to determine degradation of insulation. In this paper, we investigated the classification of PD in defects of solid insulation using a statistical method and classified patterns of PD due to surface discharge, electrical tree and void discharge by using a Kohonen network. To analysis PD we used the distribution of Hqn(q) and parameters such as peak charge, average discharge power, average discharge current, and repetition rate