In measuring 0.4 kV electrical loads for power sys-tem, watt-hour meter is unable to accurately judge the three-phase unbalanced load currents and its current loop is beneath the phe-nomenon such as flow or connection error. In order to solve this problem, the method is to collect zero sequence current in the zero line circuit, and enter into the watt-hour meter, and three-phase load current vector, and comparing the modulus values of, on busi-ness value and calculate the percentage, if beyond setting percent-age, watt-hour meter automatic alarm. Through this method can ac-curately judge the watt-hour meter the operation situation of cur-rent loop, and have played an important role in online monitoring of electric energy metering device.% 在计量0.4 kV系统用电负荷中，电能表无法准确判断出三相负荷电流不平衡与其电流回路是否有失流或接线错误等现象。针对这一问题，通过采集零线回路中的零序电流，并输入到电能表中，与三相负荷电流向量和的模数值进行比较，并计算出差值的百分数，如果超出设定的百分数，电能表自动报警。通过这种方法可以准确判断出电能表电流回路的运行情况，同时也起到了在线监测电能计量装置的作用。
展开▼
