提出了一种中性点经消弧线圈接地的电容电流测量新方法。先用极值法进行粗调谐,当发生谐振时,测量可以得到零序电压与B、c间线电压的夹角,然后利用此时零序电压与不平衡电压的相位关系,可以求得不平衡电压与B、c间线电压的夹角,任意改变电感后,很容易得到此时零序电压与不平衡电压的夹角。根据谐振等值回路可以快速求出电容上的电压,进而可快速求出对地电容和对地电阻。最后,在MATLAB中进行了仿真论证,这种方法限制条件少、操作简单可靠、精确度高,与传统的调谐方法相比,具有明显的优势。
Based on neutral-point earthling by arc suppression coil, the paper puts forward a new method of capacitance current measurement. Firstly, extremes method is used for the coarse tuning, the angle between zero sequence voltage and B, C line voltage can be measured when resonance occurs. Then, according to the phase relationship of zero sequence voltage and unbalance voltage, the angle between unbalance voltage and B, C line voltage can be calculated. After changing the inductance arbitrarily, the different angle between unbalance voltage and zero sequence voltage can be calculated easily. According to the resonant equivalent circuit, the capacitance voltage can be calculated quickly, capacitance and resistance will be acquired easily. Lastly, The method is demonstrated in MATLAB, it features few limitations, easy and reliable-operation and high precision. Compared with traditional tuning methods, the new method has the obvious advantages.