Influence of oil-paper insulation aging on frequency domain spectroscopy of high voltage bushing

Condenser core which winded by oil impregnated paper was used to simulate the main insulation of high voltage bushing in laboratory condition, and aluminum foil layers was inserted in particular location to balance electric field. Accelerated thermal aging experiment were performed on condenser core to investigate the impact of insulation aging and temperature on frequency domain spectroscopy (FDS) test result of high voltage bushing. Experiment results shows that ε', ε″ and tan δ of the condenser core increase with the increasing of aging time and measurement temperature at low frequency, while have no obvious change at high frequency; With the increase of the temperature, ε″ increase in low frequency, the frequency point where ε' change rapidly shifts to higher frequency.