变压器铁芯接地电流测量与特征分析

Measurement and Characteristic Analysis of the Core Grounding Current of Transformer

本文首先分析变压器铁芯结构和铁芯故障的影响因素。通过对正常和故障时铁芯接地电流产生的机理和电路模型,指出在三相一体的变压器结构中,铁芯接地电流含有丰富的谐波分量。通过选取典型的变压器进行铁芯接地电流的实测,进一步验证了铁芯接地电流中谐波的存在,且谐波含量大小与变压器本体结构有关。同时针对某例铁芯多点接地故障的变压器,在投切限流电阻前后进行了波形对比分析,证明了加装电阻可限制铁芯接地电流大小,但并不改变其谐波含量。

In this paper, we analyze the core structure and the influence factors of the transformer. Through the study of the mechanism and circuit model of core grounding current, the harmonic component of the core is pointed out in the single-phase transformer. By selecting the typical transformer to carry out the measurement of the core, the existence of the harmonic in the core grounding current is verified, and the harmonic content is related to the structure of the transformer. At the same time, we analyze the current waveform of a transformer core with multi-point grounding transformer. Then it is proved that the installation of resistance can limit the size of the current of the core, but does not change the content of its harmonics.