摘要
研究重复方波电压参数对变频电机绝缘局部放电起始电压(partial discharge inception voltage,PDIV)和局部放电熄灭电压(partial discharge extinction voltage,PDEV)的影响规律,有利于I型变频电机的绝缘性能评估。利用微控制器(microcontroller unit,MCU)的可编程控制及"示波器+微控制器+高压直流电源"的信号控制反馈链路,实现了变频电机绝缘PDIV及PDEV的自动测试系统;利用该系统,在不同上升时间的重复脉冲电压下,通过大量实验研究得到了双极性重复脉冲过电压对I型变频电机匝间绝缘PDIV及PDEV的影响规律及机理解释。结果表明:无论重复脉冲电压波形是否存在过电压,PDEV均小于PDIV;当重复脉冲电压波形由无过电压变化到有过电压时,PDIV及PDEV均增大,而PDIV与PDEV的差值减小。分析放电机理,认为过电压下较高的瞬时电场强度导致的场致发射是促使第一次放电产生的主要原因;借助于重复脉冲电压下局部放电相位谱图(partial discharge phase resolved,PRPD)的测试结果,认为无过电压下单周期内较多的放电次数对表面电荷积累的影响可能是导致PDIV和PDEV变化的主要因素。研究结论有望为重复脉冲电压下变频电机PDIV及PDEV的测试结论评估提供实验依据和机理解释。
When performing partial discharge inception voltage(PDIV) and partial discharge extinction voltage(PDEV)test on type I inverter-fed motor insulation under repetitive impulsive voltages, the influence of voltage parameters on PDIV and PDEV test results should be known to evaluate and to obtain objective test results. In this study, a novel test system controlled by the microcontroller unit(MCU) with feedback control signal circuits of "oscilloscope + microcontroller +high-voltage direct current(HVDC) power supply" was firstly deigned to conduct PDIV and PDEV tests automatically for many times. A great number of PDIV and PDEV tests on twisted enameled wires under different rise times were carried out, and showed that PDEV is in general lower than PDIV with or without overvoltage;when the voltage waveform changes from no overvoltage to overvoltage, both PDIV and PDEV increase, while the difference between PDIV and PDEV decreases. Analyzing results, it is driven that the main cause of the first discharge is the higher instantaneous electric field intensity under overvoltage. Based on the results of partial discharge phase resolved(PRPD) test under repetitive impulsive voltage, it is considered that the effect of more discharge on surface charge accumulation in a single cycle without overvoltage may be the main factor leading to the change of PDIV and PDV. The results provide experimental basis and mechanism explanation for the evaluation of PDIV and PDEV measurements on inverter-fed motor insulation.
作者
李金泉
王鹏
吴琦
周婉亚
杨能
LI Jinquan;WANG Peng;WU Qi;ZHOU Wanya;YANG Neng(College of Electrical Engineering, Sichuan University, Chengdu 610065, Sichuan Province, China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2019年第15期4541-4549,共9页
Proceedings of the CSEE
基金
国家自然科学基金项目(51407121)~~
关键词
变频电机
绝缘系统
重复脉冲电压
局部放电
过电压
inverter-fed motor
insulation system
repetitive impulsive voltage
partial discharge
overvoltage
