基于容性设备泄漏电流的电网电压分频测量方法分析

为优化电网过电压在线监测的测量技术,提出了一种基于测量容性设备泄漏电流的电网过电压的测量方法。该方法是使用2个不同磁导率的线圈分别获取容性设备泄漏电流中频率为30～3 000 Hz以及3kHz～1MHz的电流成分,经过积分滤波处理后将2路信号求和还原为线路电压。分析了泄漏电流与电压的传递函数,研究了电压传感器的工作原理及其影响因素。最终采用分频的方式实现了工频、操作冲击和雷电冲击过电压的测量。采用的电压传感器结构简单,与高压系统没有电气连接,具有很好的安全特性。工频、操作冲击和雷电冲击过电压试验结果表明设计的传感器具有很好的准确度和线性度,可以用于高压电网的电压测量。

Analysis on Power Grid Voltage Frequency Measurement Method Based on Leakage Current of Capacitive Equipment

On the basis of the leakage current of capacitive equipment,to optimize the on-line measurement of the power grid over-voltage,we presented a measurement method of power voltage and internal overvoltage.Two coils with different magnetic permeability were used to sense the leakage current of different frequency bands(30~3 000 Hz and 3 kHz~1 MHz).After filtering,the two parts were summed to restore the line voltage.The transfer functions between voltage and leakage current were analyzed,and the principle and influential factors on the current sensor performance were studied.Moreover,the power frequency voltage,switching and lightning impulse voltage measurement were realized by a frequency approach.The adopted voltage sensor was very simple in structure and very safe because it had no direct connection with the high voltage system.Experimental results of power frequency voltage,switching overvoltage and lightning overvoltage indicate that the voltage sensor has good precision and linearity,and can be used to measure the voltage of high voltage power grids.