电流型电子式电压互感器的温度稳定性研究

针对一种电流型电子式电压互感器(EVT)的温度稳定性进行了分析,指出高压电容器和一次侧信号处理单元中的积分电路是影响其温度稳定性的主要环节. 设计了利用正、负温度系数数值相等的多个电容单元串联组成高压电容器的温度补偿方案,有效地改善了高压传感部分的温度稳定性;提出利用热敏电阻对积分电容的温度特性进行补偿的方法,减小了温度变化给积分电路带来的误差. 依照IEC60044-7的要求,对研制的110 kV电流型EVT样机进行了温度影响准确度试验,试验结果表明设计的温度补偿方案有效,互感器在-40 ℃～+70 ℃温度范围内,满足0.2级测量准确度要求. 

Research on the Temperature Stability of the Electronic Voltage Transformer Based on Current

The temperature stability of an electronic voltage transformer (EVT) based on current was analyzed. It was presented that the high voltage capacitor and the integral circuit in the primary-side signal processing unit were two main influencing factors. The temperature compensation scheme that employing a number of capacitors with positive temperature coefficient and with the same value negative temperature coefficient in serial connection to comprise the high voltage capacitor was designed, which can improve the temperature stability of the high voltage sensor. The method of using the thermal resistor to compensate the temperature characteristic of the integral capacitor was proposed, reducing the error introduced by the temperature change. According to IEC60044-7, the accuracy versus temperature test on the developed 110 kV EVT prototype was carried out. The results show that the designed compensation schemes are effective and the EVT is compliant with the 0.2 measurement precision class over the temperature range from 40 ℃ to +70 ℃.