谐波电流对感应式有功电度表计量的影响

谐波对感应式有功电度表计量误差的影响主要表现为谐波电能和谐波电流的影响，其中谐波电流产生的误差由于原因较为复杂不易估计。文章对谐波电流产生的测量误差进行了较全面的分析，将误差分割为补偿误差，附加转矩误差和波形误差三部分。其中补偿误差由电流元件中的过载分磁板引起，附加转矩误差由电压圈的套饱和现象所产生的等效附加谐波电压与线路同次谐波电流作用所引起；对波形误差分析了波形的断续对误差的影响，文章对前两种误差进行了定性和定量分析，对波形主要给出测量结果。分析及测量结果显示，误差主要由补偿误差和附加转矩误差构成，基本可忽略波形断续所产生的误差。由测量结果还可以看出，高压电网中由于谐波电流不显著，基本可忽略其影响；低压电网中，尤其是民用线路中，由于存在显著的谐波电流，特别是3次谐波电流，因谐波电流产生的误差有时是不能忽略的。

INFLUENCE OF HARMONIC CURRENT ON METERING ERROR OFINDUCTION PHASE WATT-HOUR METERS

The influence of harmonics on induction watt-hour meter is expressed as the superposition of harmonic energy and harmonic current respectively, because the cause of metering error by harmonic current is rather complicated, so it is hard to estimate. In this paper the metering error caused by harmonic current is divided into three parts, i.e., the compensation error which is due to the dividing flux plate, the additional torque error which is due to the additional harmonic power led by the joint action of equivalent additional harmonic voltage caused by the saturation of voltage coil and the harmonic current with same order in the power line and thirdly waveform error. The first two errors are analyzed quantitatively and qualitatively, for the third error merely the influence of the interruption of current waveform on the error is analyzed and the measured results of this kind of error are given. The results of analyses and measurements show that the metering error is mainly consisted of the first two errors and the third kind of error can be neglected. In the measured results it can be seen that in high voltage power networks because the harmonic current is not notable so its influence can be not considered, however, in low voltage distribution networks the harmonic currents, especially the third order of harmonic current, is remarkable, therefore, sometimes the metering error caused by harmonic currents can not be neglected.