倒立式SF_6同轴电容高压电子式电压互感器

Inverted SF_6 Coaxial Capacitance Electronic Voltage Transformer for High Voltage Systems

针对目前类似多级电容串联分压结构的电子式电压互感器的不足之处,设计了一种新型的电子式电压互感器。该互感器采用传统倒立式SF6互感器的绝缘结构,通过在高压电极和地电极之间构造中间同轴电极形成SF6同轴分压电容,检测SF6同轴电容的电容电流iC即可获得高压侧被测电压大小。该互感器的主要特点是利用高压壳体与接地金属屏蔽罩的双重屏蔽作用,有效地提高分压电容的抗外界杂散电场干扰能力和稳定性。该文对位置、温度、压力等影响同轴电容大小的因素进行了仿真计算。在国网电力科学研究院对研制的高压电子式电压互感器进行了型式试验。仿真和试验结果表明,该电子式电压互感器准确度达到了IEC 60044-7规定的0.2级精度要求。

In accordance with the shortcomings of electronic voltage transformers with the structure of cascaded parallel capacitor divider,we have designed a new type of electronic voltage transformer of high voltage.It has a SF6 coaxial capacitance sensor in differential pressure and ground potential with its measurement subsystem,and can obtain the voltage on the high-voltage side through the capacitance current.By using the high-voltage shell and the ground potential metal cap as shield,the capability of resisting disturbance and the stability of the coaxial capacitance can be effectively enhanced.Utilizing mathematical models,we analyze some parameters such as the capacitance＇s position,the gaseous tension,and the ambient temperature.Tests are performed in the State Grid Electric Power Research Institute of China.Both of calculation and the test results show that the presented voltage transformer fulfills the precision requirements of the 0.2class in IEC 60044-7.