电子式电压互感器传感器设计

Design of sensor for electronic voltage transformers

为适应配电自动化和数字变电站的需要,研制出应用于电子式电压互感器的传感器。该互感器以电容分压器为基础,其中电容分压器由金属导电棒、双面柔性电路板和聚四氟乙烯组成的等效电容构成。用柔性电路板可将前级放大电路放在传感器的内部,以提高系统的信噪比和测量精度。采用介电性能与温度、频率无关的聚四氟乙烯作为绝缘材料,可有效地减少温度和频率对测量的影响,并增加了系统的稳定性。最后,Matlab仿真证明该传感器具有良好的暂态响应;多次试验结果表明由该传感器组成的电子式电压互感器样机测量精度为0.2级。

The sensor for electronic voltage transformers is designed to meet the requirements of distribution automation and digital substation. It is based on a capacitive voltage divider consisted of two equivalent capacitors,which arc composed of the metal electrode,double- sided flexible circuit board and polytetrafluoroethylene. Pre- amplifier is designed inside the sensor to increase the signal- to- noise ratio and measurement accuracy. The polytetrafluoroethylene,immune to temperature and frequency change,is used as the insulation material to improve the measurement stability and reduce the influence of temperature and frequency on measurement. Simulation with Matlab proves the sensor has an excellent transient response. A prototype of electronic voltage transformer consisted of it is tested,showing its measurement accuracy of 0.2 class according to IEC standard.