Partial discharges in insulation of medium voltage systems

The term "partial discharges" (PD) is a common term for various phenomena: discharges at points or edges of cylindrical conductors, in gases and gas i nsulated devices, liquid insulation materials, at borders between different insulation materials and, of course, in solid dielectrics. These phenomena result in insulation breakdowns, various disturbances to the environment, and after longer periods, some large-scale failures. This paper presents th e results of theoretical research of the behavior of a system of medium vol tage covered conductors This research work has been elaborated by the use o f computer aided electric field calculations. For the confirmation of theor etical findings, practical measurements of partial discharges have been mad e.