The Influence of Multi-Factor Aging on Partial Discharge Property for Epoxy/Mica Insulation of Generator Stator Bars

As one of the most important parts of the generator, Epoxy/mica insulation system has the direct effect on the reliability of generator operation. The accelerated aging of insulation system was taking place under the complex operation condition, and resulting in the insulation system breakdown. It had always been the target for the researchers to find an efficient way to evaluate the state of generator insulation system. According to the real operation situation, the multi-factor aging test sequence with electric field, temperature field, mechanical vibration and thermal cycling was developed, and the test platform with multi-factor aging was built in this research. The partial discharge test was conducted at the end of each cycle. The result showed that, with the insulation aging time prolonged, the maximum partial discharge quantity decreased first then increased while skewness and kurtosis varied the opposite way. And the phase range of partial discharge began to expand. This research provided a new way to evaluate the state of generator insulation system.