三相四线电能表失压退补电量的误差研究

Error Research of Retrieving Electric Power Due to Voltage Loss in Three-phase Four-wire Watt-hour Meter

为了研究"电压替代法"在三相电网不对称时退补电量的误差范围,采用"对称分量法"对"电压替代法"退补电量的更正功率误差进行了分析计算,导出三相四线电能表失压退补电量的更正功率在电网三相电压、电流不平衡状态下的误差表达式.根据误差表达式分析实际运行的功率因数及三相电压、电流不平衡度在一定范围变化时更正电量误差变化情况,并计算在电网相关约束条件下的误差、样机实测不平衡度的误差及某实际电网95%的三相电压幅值不平衡时的误差,结果显示其误差小于±3%.最后比较了C相电流取不同电流时,"电压替代法"和"更正系数法"的更正功率的计算误差,说明在三相不平衡负荷下"电压替代法"计算的退补电量误差远小于"更正系数法"的误差,得到的结果验证了该方法的可行性和实用性.

In order to study the error range of the voltage substitution method in the asymmetry of the threephase power grid.Used symmetrical component method to do a series of analytical calculation for the correction power error of the voltage substitution retrieving electric power. The Three-phase Four-wire Watt-hour Meter loss voltage error formulas of the corrected power are derived when three-phase voltage and current are unbalanced in the power grid.Not only did it analyze the power factor of actual operation and the degree of unbalanced three-phase voltage and current changes in a certain range correction power error,but it also calculate the error of the relevant constraints in power grid,the prototype measurement error of the unbalanced degree and some 95% of the actual power grid when the unbalanced three-phase voltage amplitude error curve,the error is less than±3%.At last,compared the difference between the voltage substitution and the correction coefficient when c-phase current is different,shows that the first method is far less than the error of the correction coefficient method.The results verify the feasibility and practicability of this method.