重复脉冲参数对变频电机绝缘PDIV测试信噪比影响研究  

Influence of Repetitive Impulse Voltage Parameters on the Signal-to-noise Ratio of PDIV Test for Inverter-fed Motor

作　　者：李佩宜 王鹏[1] 马世金 董涵 顾洋豪 周婉亚 LI Peiyi;WANG Peng;MA Shijin;DONG Han;GU Yanghao;ZHOU Wanya(College of Electrical Engineering,Sichuan University,Chengdu 610065,China;Southwest Electric Power Design Institute,Chengdu 610021,China)

机构地区：[1]四川大学电气工程学院,成都610065 [2]西南电力设计院有限公司,成都610021

出　　处：《高电压技术》2021年第8期2981-2990,共10页High Voltage Engineering

基　　金：国家自然科学基金(51977134)。

摘　　要：为研究强电磁干扰环境下复杂脉冲电压参数对局部放电起始放电电压(partial discharge inception voltage,PDIV)测试信噪比的影响,基于特高频检测法,在不同重复脉冲电压上升时间、频率和占空比下进行变频电机绝缘PDIV测试,并分析放电信号的时域和频域特性。研究表明,脉冲上升时间对0.5GHz以上高频放电能量影响显著,高频能量随上升时间增加而衰减,在不同上升时间下频域滤波会削弱放电能量,造成测试信噪比降低;脉冲频率升高,放电幅值减小且高频放电能量微弱,放电更易淹没于残余电力电子器件干扰中;具有较小占空比的脉冲电压下(如占空比为0.03%),下降沿处出现统计时延较短的小幅值放电,此时检测上升沿放电可适当提高PDIV测试信噪比。在执行低压散绕变频电机绝缘PDIV测试时,以上结果有望为重复脉冲电压参数选择和测试信噪比的提高提供参考依据,从而提升变频电机绝缘评估准确度。To study the influence of complex impulse voltage parameters on the signal-to-noise ratio(SNR)of partial discharge inception voltage(PDIV)test under strong electromagnetic interference,based on the ultra-high frequency method,the insulation tests of inverter-fed motor under different rise time,frequency and duty cycle were performed,and the characteristics of PD signal in time domain and frequency domain were analyzed.The results show that the rise time has a significant effect on the high-frequency energy of discharge greater than 0.5 GHz.The high-frequency energy decreases gradually with the increase of rise time.The high-pass filter will weaken the discharge energy under different rise time,resulting in the decrease of the test SNR.The discharge amplitude decreases with the frequency increasing,and the discharge energy in high-frequency domain is weak.The discharge is more likely to be submerged in the residual interference.The discharge amplitude at the falling edge is small and the delay time is short under voltage of small duty cycle,such as 0.03%duty cycle.At this time,The SNR in PDIV test can be improved by detecting the partial discharge at the rising edge.The above results can provide a reference for the selection of repetitive square wave voltage parameters and the improvement of the SNR in the PDIV test,so as to improve the accuracy of insulation evaluation for inverter-fed motors.

关 键 词：变频电机 脉宽调制 绝缘系统 局部放电 电磁干扰 信噪比 

分 类 号：TM344.6[电气工程—电机]