基于开合式电容传感方法的电压互感器误差带电校验系统

Study on Voltage Transformer Error Online Calibration System Based on Open-closed Capacitor Sensing Method

为了保证电压互感器的准确度和可靠性,需要对其进行准确度校验。传统校验方式定期进行,需要线路停电,周期较长,无法及时发现互感器存在的问题。针对这种情况,文中提出了一种基于开合式电容传感方法的电压互感器误差带电校验系统,利用采用两个开合式电容器及其他辅助器件构成的电压传感器作为标准传感器,利用两开合式电容器输出相互比对的形式实现传感器准确度自检,并利用其输出的平均值作为最终输出,大大提高了校验准确度及可靠性。测试结果证明该带电校验系统在额定电压的20%～120%范围内,比差变化小于0.037%,角差变化小于0.45′。

To ensure the accuracy and reliability of a voltage transformer,it is necessary to calibrate its accuracy.However,the traditional calibration method needs to be carried out periodically in the condition of outage,and some-times it cannot find transformer’s fault due to longer calibration time. In view of the fact,this paper proposes a volt-age transformer error online calibration system based on the open-closed capacitor sensing method. In this method,two open-closed capacitors and other auxiliary devices are used to compose a voltage sensor,and it is taken as the standard sensor. The outputs of the two open-closed capacitors are compared with each other to achieve self-test of sensor accuracy,and the average value of the outputs is used as the final output. Hence,the accuracy and reliability of the calibration are greatly improved. Test results show that the present system works within 20%~120% of the rated voltage,the variation of the ratio error is less than 0.037%,and the variation of the phase error is less than 0.45′.