电力行业标准异频法公式勘误与电容电流测试新方法

Formula Erratum for Non-power Frequency Method in Power Industry Standard and New Measuring Method of Capacitive Current

指出并验证了电力行业标准中"三异频等幅电流阻抗法"计算电容和电容电流公式的错误,推导得出了正确的计算公式。此外,针对从电压互感器开口三角注入异频电流测量电容电流方法存在效率低、安全性及准确性不高等缺点,提出了一种从电容器组中性点注入异频电流测量电容电流的方法,通过数学理论推导、模拟试验和现场测试对该方法的准确性进行验证,同时由模拟试验结果分析了各种因素对新方法测试误差的影响。

The errors in formulas for calculating the capacitance and the capacitive current by the ＂three non-power frequency current with equal amplitude impedance method＂ in the power industry standard are introduced and verified, the correct calculation formulas are derived. In addition, the shortcomings of low efficiency, insufficient security and accuracy in measuring capacitive current by injecting non-power frequency current from the potential transformer （PT） open delta side are studied. Then a new capacitive current measuring method of injecting non-power frequency current from the neutral point of a capacitor bank is proposed. With the help of mathematical theory-based derivation and experimental results and field tests, the accuracy of this method is verified while the influence of various factors on the test error with the new method is analyzed by the simulation test results.