摘要
为提高变频电机绝缘局部放电(PD)测试信噪比,在上升时间为200ns的连续方波电压下,研究了电机绝缘局部放电和方波电源干扰的时频特性,总结出连续方波电压频率和占空比对局部放电统计特性的影响规律。研究结果表明,局部放电和方波电源干扰能量分别集中在0～1.8GHz和0～0.5GHz频率范围内,局部放电电压幅值随着连续方波电压频率的增大而减小,较小连续方波电压占空比易造成局部放电淹没在电压下降沿处的方波电源干扰中。据此,在对变频电机绝缘进行局部放电测试时,为抑制方波电源干扰,宜采用截断频率为0.5GHz的高通滤波且应使超高频天线在0.5～1.8GHz频率范围内具有良好的响应性能。另外,为提高测试信噪比,推荐采用频率<200Hz、且占空比为50%的连续方波电压作为测试电应力。
In order to increase the signal-to-noise ratio of partial discharge （PD） detection on inverter-fed motors, both time and frequency features of PD and generator induced disturbance were studied under square-wave voltages with 200 ns rising time, and PD statistical characteristics with different square-wave voltage frequencies and duty cycles were obtained. Experimental results show that, the frequency energy of PD and generator induced disturbance mainly distribute in frequency ranges of 0--1.8 GHz and 0--0.5 GHz, respectively. Higher square-wave voltage frequency will give rise to PD pulses with lower magnitude, and square-wave voltage having small duty cycle will have PD submerged in the generator disturbance during voltage fall. Accordingly, when performing PD detections on inverter-fed motors, to suppress the power disturbance, high pass filters with cut frequency of 0.5 GHz should be adopted, and ultra high frequency sensors should have excellent response performance in the frequency range of 0.5 --1.8 GHz. Furthermore, to increase the signal-to noise ratio, repetitive square-wave voltages having frequency less than 200 Hz and duty cycle of 50~ is recommended to be the testing voltages.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2013年第6期1522-1526,共5页
High Voltage Engineering
基金
国家自然科学基金(51177136)~~
关键词
变频电机
连续方波电压
绝缘系统
局部放电
信号调理
超高频
inverter-fed motor
repetitive square wave voltage
insulation system
partial discharge
signal conditioning
ultra high frequency
