电源谐波对介质损耗测量的影响

Effects of harmonic components of power supply on the dielectric loss measurement

通过理论分析和试验实测研究了电源中的各种谐波对西林（Ｓｃｈｅｒｉｎｇ）电桥以及数字介质损耗测量系统中各个环节的影响。对西林电桥来说，检流计对谐波具有很强的抑制作用。文中发展了一种介质损耗的数字测量系统，其原理是测量电压和电流过零的时间以求取介质损耗角。在分析了谐波的频率、幅值、相位等对介质损耗测量的影响后，建议采用低通滤波器，以消除谐波所带来的误差。如果将三次、五次和七次谐波分量分别限制在１％、０．３％和０．１％以内，谐波的影响可以忽略不计。

The effects of various harmonic components of power supply voltage on the dielectric loss measurement are analyzed in detail. For the Schering bridge, the effects of harmonic components are limited by the vibration galvanometer. In this paper a digital measuring system of dielectric loss was developed. The principle of this system is to measure the times of null voltage and null current. In order to reduce measuring errors of the system, it is suggested to use a low pass filter. If the third, fifth and seventh harmonic components are limited to values less than 1%,0.3% and 0.1% respectively, the effects of various harmonic components on the dielectric loss could be negligible.