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 layer propyl ene (PP) capacitor film for destruction from partial discharges (PD) and fr om arcing with impregnated silicons fluids of different viscosity. A specia l method of testing is presented. The testing was carried out On specimens ns which modelled a capacitor dielectric system containing the metallised P P film and silicone impregnating fluid. The characteristics of PDs were mea sured by means of a pulse-height analyser with a detection level of 10(-13) C. The arcing voltage between the high-voltage electrode and measuring ele ctrode was measured by; means of a disconnecting device whose disconnect ti me is less than or equal to 20 mu s. In both specimens the object under tes t uns the metallised 8 mu m PP film. with an Al metallised laver of 4 Omega surface resistance. The time dependence of destroyed length. the frequency dependence of electrode erosion rate and the relationship between electrod e gap distance and arcing voltage are given.