Comparative aging characteristics of oil-impregnated-paper bushings of different thicknesses subjected to switching surges

Partial discharge tests of oil-impregnated paper capacitor bushings, subjected to voltage switching surges, indicated that overstressed solid-liquid insulation may recover following an electrical stress-free period. However to ensure long term performance of the insulating system, the elevated stresses arising from the superimposed voltage switching surges must be reduced by an increase in the insulation thickness.