一种新的MOA阻性电流提取算法

Calculation of MOA resistive current

根据小电流区金属氧化物避雷器(MOA)等值电路模型为非线性电阻和电容并联的原理分析了非线性电阻和电容产生的电流,指出二者之间存在正交关系,并进行了证明。在此基础上提出了一种获取MOA泄漏电流中阻性分量的方法。即使MOA电阻的非线性关系和晶介电容值未知时,理论上该方法仍然可以获得准确的阻性电流,且不受电压信号中存在谐波的影响,同时可以获得准确的晶介电容值。基于Matlab实现了多种算法,使用MOA模型仿真出了电压和泄漏电流信号,多种方法的计算结果中所提算法具有最小误差,电压谐波存在时误差均为0;实验室实测了10 kV MOA的电压和泄漏电流,计算结果表明所提算法具有最高的稳定性。

The equivalent circuit model of MOA（Metal Oxide Arrester）,which is the paralleling of nonlinearresistor and capacitor,is analyzed and the orthogonal relation between resistive and capacitive currents isproved. A method to calculate the resistive component of MOA leakage current is presented. Theoretically,even if the nonlinearity of resistor and capacitance are unknown,accurate resistive current and capacitanceof MOA can be obtained,immune from the voltage harmonics. Several algorithms of MOA resistive currentcalculation are realized with Matlab and used to calculate the resistive current based on the simulatedvoltage and leakage current signals of MOA model,which indicates that,the proposed method has thesmallest error,being zero even when voltage has harmonics. The actual voltage and leakage current signalsof 10 kV MOA are obtained by experiments and the proposed method has the highest stability.