变压器直流扰动下励磁谐波与铁心饱和失稳研究

变压器遭受直流入侵时铁心励磁饱和程度加深,励磁电流发生畸变,谐波含量显著升高。针对该问题研究变压器励磁谐波与铁心饱和特性,并提出一种变压器直流扰动下铁心饱和失稳判据。基于电磁耦合原理构建交直流混杂模式下的变压器状态方程,利用端口电气信息研究励磁电流辨识方法,对励磁电流进行谐波分析并总结其变化规律,通过分析变压器直流扰动铁心饱和机理,研究铁心饱和失稳判别方法。通过仿真计算与动模实验深入分析变压器的电磁特性,并验证该方法的有效性。该研究为变压器直流扰动下铁心饱和失稳判别提供可行方法。

Research on excitation harmonics and core saturation instability of transformer under DC disturbance

Excitation saturation of core is deepened when the transformer is subjected to DC invasion, which causes excitation current to distort and harmonic components are increasing significantly. In this paper, the characteristics of excitation harmonic and core saturation are studied, and a criterion for core saturation instability of the transformer DC disturbance is proposed. Based on the principle of electromagnetic coupling, the state equation of transformer in AC / DC hybrid mode is constructed, then the identification method of excitation current is studied based on port electrical information. The harmonic of excitation current is analyzed and its variation law is summarized, furthermore, the discriminating method of core saturation instability is studied by analyzing the saturation mechanism of the transformer under DC disturbance. The electromagnetic characteristics of transformer are analyzed through calculation and dynamic simulation experiment and the effectiveness of this method is verified, which provides a feasible method for discriminating the saturation instability of core under DC disturbance. This work is supported by National Natural Science Foundation of China (No. 51507027).