电子式电能表工频外磁场试验方法的探讨

Discussing the test method of power frequency magnetic fields to electronic energy meter

分析了电子式电能表工频外磁场试验引入的附加误差与试验条件的关系。针对国标规定的电能表工频外磁场试验方法不能保证锰铜分流器变换式电能表在其全电流量程内的抗工频外磁场能力,提出在电能表电流测量范围的下限,即10%Ib(直接式)、5%In(互感式)进行该项试验的改进型试验方法。经计算,电能表若满足文章建议的试验要求,其在该工频磁场下的感应电流必小于起动电流,不会出现空载走字。对国网新增工频磁场潜动性能试验的测试时间合理性进行分析,提出应以不大于1/0.6倍理论起动时间的看法。测量统计了我国近5年内锰铜分流器变换式电能表的抗工频外磁场能力,总体看该性能逐年提升,在2014年有较大提高(附加误差<0.2%)。

The relationship between test conditions for power frequency magnetic fields of external origin and the measurement additional error of energy meter was analyzed .According to international regulation that external power frequency magnetic field test method of electric energy meter can not ensure the anti power frequency magnetic field as using copper-manganese shunt energy meter , so it presents the lower bound of energy meter current range , that is 10%Ib （direct type） and 5%In （mutual inductance） to carry out the improved test.Simulation indicates, if meter meet the test requirements of 0 .5 mT power frequency magnetic field at the load point suggested in article , it can en-sure the induced current is less than the starting current .To the test method of no load test in the power frequency magnetic field , it discusses its rationality of test time , and the view that the theorotical starting time should be no more than 1/0.6 times is presented.Statistical measuring additional errors of different types of energy meter using copper-manganese shunt in the past 5 years,we find that the anti power frequency magnetic field capacity of energy meter in-creased year by year , and it has a breakthrough improvement （〈0.2%） in 2014.