ϕ-q-n pattern analysis for understanding partial discharge phenomena in narrow voids

Partial discharge (PD) often starts from the voids enclosed in insulation and/or at interface defects and ultimately causes damage to the insulation. Partial discharges result in failure of the insulation much before the expected lifetime. In the present paper, discharge phenomena in small spherical voids enclosed inside a solid insulation and its relation to the modern phase resolved measurement techniques is investigated. A circuit level electrical model is used to simulate PD process in a narrow void present inside a solid insulation. The model has been built using the tools of OrCADpsilas PSpice software for analogue design and simulation. The inception and extinction of PD, shape of PD patterns in the form of pulse count and the amount of charge, which is released during PD for different cases, are studied and reported in this paper. Experimental results in equivalent systems have been compared with the data obtained from the simulation results.