特高压直流输电线路等效干扰电流的计算以及影响因素的研究

Computation of Equivalent Disturbing Current in UHVDC Power Transmission Lines and Analysis on Its Influencing Factors

高压直流输电工程中,常以等效干扰电流作为限制直流谐波水平的标准。为了计算出准确的等效干扰电流,利用3脉动模型,对特高压直流输电工程进行了建模,计算了不同的直流滤波系统参数的等效干扰电流,得出了等效干扰电流随直流滤波系统中各部分参数变化的规律,即:等效干扰电流随平波电抗器电感值的增大而减小,随中性线接地电容的增大而减小,随直流滤波器高压电容值的增加而减小,并分别得出了变化规律曲线;文中还给出了使等效干扰电流满足允许值要求的滤波系统参数。

Equivalent disturbing current is used as the standard of restricting harmonic current level at DC side in HVDC project. To compute accurate equivalent disturbing current, using 3-pulse model the UHVDC power transmission project was modeled and equivalent disturbing currents under different parameters of DC filtering system were calculated, thus following rules of equivalent disturbing current varying with parameters of component parameters were attained： theequivalent disturbing current decreases with the increase of inductance value of smoothing reactor; it decreases with the increase of neutral-line-to ground capacitance; it decreases with the increase of capacity of HV capacitor of DC filter, and corresponding varying curves were obtained. Besides, the parameters of the filtering system, by which the equivalent disturbing current could meet the requirement of the allowable value, were proposed.