Effects of silicone impregnant viscosity on metallised layer of polypropylene capacitor film under partial discharges

The authors present results of testing the metallised layer of polypropylene (PP) capacitor film for destruction from partial discharges (PD) and from arcing with impregnated silicone fluids of different viscosity. A special method of testing is presented. The testing was carried out on specimens which modelled a capacitor dielectric system containing the metallised PP film and silicone impregnating fluid. The characteristics of PDs were measured by means of a pulse-height analyser with a detection level of 10/sup -13/ C. The arcing voltage between the high-voltage electrode and measuring electrode was measured by means of a disconnecting device whose disconnect time is /spl les/20 /spl mu/s. In both specimens the object under test was the metallised 8 /spl mu/m PP film, with an Al metallised layer of 4/spl Omega/ surface resistance. The time dependence of destroyed length, the frequency dependence of electrode erosion rate and the relationship between electrode gap distance and arcing voltage are given.