电压频率和环境湿度对聚酰亚胺薄膜局部放电特性的影响

Effect of Voltage Frequency and Ambient Humidity on Partial Discharge Characteristics of Polyimide Films

环境应力和高频电应力引起的局部放电是造成电力电子变压器绝缘过早失效的主要原因。为研究电压频率和环境湿度对聚酰亚胺薄膜局部放电特性的影响,基于恒温恒湿控制箱和高频正弦电源构建了局部放电测试平台,在不同相对湿度(30%~80%)和频率(10~30 kHz)下研究了聚酰亚胺薄膜的局部放电特性。结果表明:局部放电平均放电次数和幅值随着相对湿度的增加呈现先减后增的趋势,且转折点随着频率的增加向相对湿度较低的方向转移;在相对湿度较低(30%~50%)时,随着频率增加,局部放电平均放电次数减少、幅值减小;而在相对湿度较高(60%~80%)时,随着频率增加,局部放电平均放电次数增加、幅值增大。

Partial discharge(PD)caused by environmental stress and high frequency electrical stress is the main reason for premature failure of power electronic transformer insulation.In order to research the effect of voltage frequency and ambient humidity on PD characteristics of polyimide film,a PD test platform was constructed based on a constant temperature and humidity control box and a high frequency sinusoidal power supply.The PD characteristics of polyimide films were investigated at different relative humidity(30%~80%)and frequency(10~30 kHz).The results show that with the increase of relative humidity,the average discharge number and amplitude of PD decrease at first and then increase,and the turning point moves to the direction of lower relative humidity.Under lower relative humidity(30%~40%),the average discharge number and amplitude of PD decrease.Under higher relative humidity(60%~80%),the average discharge number and amplitude of PD increase.