Effects of silicone impregnant viscosity on metallised layer of polypropylene capacitor film under partial discharges [and reply]

The author comments on the work of A.M. Andreyev et al. (ibid., vol. 146, pp. 70-2, 1999) regarding the effect of impregnant viscosity on metallised layer of polypropylene (PP) capacitor film under partial discharge activity, It seems that high impregnant viscosity is beneficial to the performance of the insulating system since the destroyed region length for metallised PP film decreases as the polymethylsiloxane viscosity increases, It has been reported, however, elsewhere that low impregnant viscosity, among other factors such as low dissipation factor, exceptional resistance to discharge, high inception voltage and gas absorbing properties is of paramount importance for a capacitor. The question of how these results can be reconciled is examined