Study on Thermal Aging Characteristics of Epoxy Resin Impregnated Paper for Bushing

Abstract

Epoxy resin impregnated paper is the main insulating material of the RIP bushing which is widely used in electric power system, but the heat dissipation performance of epoxy resin impregnated paper is not good and the problem of thermal aging occurs, which seriously affects the safe operation of RIP bushing. In order to study the effect of thermal aging time on the FDS measurement results of epoxy resin impregnated paper, a long-time accelerated thermal aging test is carried out at 100°C for the same epoxy resin impregnated paper sample in different aging stages. The real part of capacitance of the sample at each aging stage decreases with the increase of frequency. With the increase of aging time, the frequency spectrum of imaginary part of capacitance and dielectric loss moves upward, and in the low frequency range of 0.002 Hz$\sim$1 Hz, it increases obviously with aging time and decreases with the increase of frequency, there is a peak value which increases with the increase of aging time at about 20Hz. With the increase of aging time, the power frequency dielectric loss of the sample increases gradually, after 1000 h of thermal aging, the power frequency dielectric loss of the sample increases to 2.04%, which is 4.9 times of that of the sample without aging. The conclusions provide design and operation basis for the safe operation of RIP bushing.