基于电荷补偿的金属化膜电容器自愈测试方法

Test method of self-healing in high voltage metallized film capacitors based on charge compensation

利用金属化膜电容器发生自愈时会引起电容极板间电压下降,并使与其并联的储能电容为其充电以补偿电荷这一原理,设计了一种较为简单、有效的自愈测试方法。该方法利用示波器监测自愈发生时储能电容给被测电容的充电电流作用于采样电阻而形成的脉冲电压信号,以该信号的出现作为判断自愈发生的依据,并根据该信号特性计算自愈能量损失。仿真和实验结果证明,该方法能够较为准确地检测到自愈的发生,并计算出自愈造成的能量损失,30个实际测试样本数据显示,采用该方法计算的自愈能量损失与实际自愈能量损失相比,其误差范围在-3.83%～5.71%内,有较高的准确度。

A simple and effective test method is designed based on the principle that self-healing could cause the voltage falling between the under test capacitor’s electrode and makes the parallel capatior charge up for its charge loss.This method utilizes oscilloscope to monitor the pulse voltage signal produced by the pulse current signal from the charge up operation on the sampling resistance,taking this signal as a symbol of self-healing occurrence and calculating self-healing energy loss according to this signal’s character.Simulation result and real test show this method could detect self-healing’s occurrence and calculate self-healing energy loss precisely.Data from30test samples revals that,comparing the energy loss given by this method with the real self-healing energy loss,the error is about-3.83%-5.71%,and the precision is comparatively good.