基于高斜率PWM脉冲发生器的煤矿电机局部放电特性检测试验系统  

Research on testing system of partial discharge characteristics for mine motor based on high slope PWM pulse generator

作　　者：冯琛 高志宣[1] 魏可可 陈鹏 王彦文[1] FENG Chen;GAO Zhixuan;WEI Keke;CHEN Peng;WANG Yanwen(School of Mechanical Electronic&Information Engineering,China University of Mining&Technology(Beijing),Beijing 100083,China;The Ohio State University,High Voltage Lab,Columbus 43210,USA)

机构地区：[1]中国矿业大学(北京)机电与信息工程学院,北京100083 [2]美国俄亥俄州立大学高电压试验室,哥伦布43210

出　　处：《煤炭学报》2019年第S02期808-816,共9页Journal of China Coal Society

基　　金：国家留学基金委资助项目(20173109)。

摘　　要：局部放电严重损害煤矿电机运行,而高斜率(dv/dt)的脉宽调制(PWM)脉冲是造成电机绕组局部放电的最关键原因之一。随着电力电子技术的发展,电机驱动普遍采用变频器,而变频器驱动电机运行时会在电机绕组和变频器或电缆中产生高斜率PWM脉冲,高斜率的PWM脉冲电压相比工频交流电压更容易产生局部放电。在煤矿电机局部放电检测及特性测试中,为了模拟变频器在驱动煤矿电机时产生的高斜率PWM脉冲波进入煤矿电机绕组中而导致的绕组匝间局部放电,需要一种能产生高斜率的脉冲发生器模拟煤矿电机局部放电现象,现有的局部放电测试脉冲发生器无法产生具有微秒上升时间的超高dv/dt脉冲。针对这一问题,设计了一种新型具有超高dv/dt输出的脉冲宽度和频率可调的新型脉宽调制脉冲发生器和以该发生器为基础的煤矿局部放电特性试验系统。该脉冲发生器可以发出双极±1.2 kV上升速率为±50 kV/μs的脉冲,且单极性输出1.2 kV电压的上升速率可达250 kV/μs,发出的PWM脉冲的宽度和频率可以实现精确控制。并利用设计的检测装置进行模拟煤矿电机局部放电特性试验,验证了此脉冲发生器用于测量电机局部试验的可行性。通过模拟试验得出被测模拟电机绕组局部放电的特性为电流频率在1.2~1.9 GHz,中心频率为1.5 GHz,验证了设计的模拟试验装置和试验系统可以用于探究煤矿电机绕组局部放电的特性。Partial discharge seriously damages the operation of mine motors.Moreover,high slope(dV/dt)pulse width modulation(PWM)pulse is one of the most critical causes of partial discharge in motor windings.The reason is that with the development of power electronics technology,motor drives generally adopt frequency converters.However,the high-slope PWM pulse is generated in the motor winding and the inverter or cable when the inverter drive motor is running.Compared with power frequency ac voltage,the PWM pulse with high dV/dt is easier to generate partial discharge.Based on partial discharge detection and characteristic testing of mine motor,in order to simulate PWM pulse wave from frequency converter in mine motor,a pulse generator with high dV/dt is urgently needed for the signal injection of Cable Partial Discharge detection.However,the existing pulse generator for partial discharge testing cannot generate ultra-high dV/dt pulses with microsecond rising time.To address this problem,a new type of PWM pulse generator with ultra-high dV/dt output is designed.The pulse generator can emit the bipolar(±1.2 kV)pulse with the slew rate of(+50 kV/μs),and per unit polar output waveform can reach to 1.2 kV with the rising rate of 250 kV/μs.In this study,the partial discharge characteristic test of the coal mine motor was carried out by using the designed detection device,which proved the feasibility of the pulse generator for measuring the local test of the motor.The characteristics of partial discharge in the coal mine motor are further explored.Through the simulation test,the partial discharge characteristics of the tested analog motor winding sample is in the range of 12-19 GHz,and the center frequency is 15 GHz.

关 键 词：煤矿电机 PWM发生器 高斜率 局部放电检测 

分 类 号：TD614[矿业工程—矿山机电] TM855[电气工程—高电压与绝缘技术]