网侧电压不对称下负载不平衡电流计算方法

A Novel Method for Calculating Unbalanced Load Current under Asymmetric Grid-Side Voltage

中文关键词:负载不平衡  完美负载  集总参数  分数阶结构

keywords:unbalanced load  perfect load  lumped parameters  fractional-order structure

中文摘要:针对现有方法无法有效分离并准确计算网侧电压不对称下负载不平衡电流的不足，提出了一种适用于配电网公共连接点处的负载不平衡电流计算方法。依据德国 DIN40110-2 标准对完美负载定义及负载电流分解的基本思想，通过计算负载不平衡等效电导和集总参数，利用分数阶结构算法优越的负序频率选频特性，从正交电流中提取出负载无功不平衡电流，实现在电压不对称条件下对负载不平衡电流的分离与计算。实验分析表明，所提方法可在时域内直接对网侧电压不对称下负载不平衡电流进行准确计算。

Abstract:To overcome the limitations of existing methods in effectively separating and accurately calculating load unbalance currents under asymmetric grid voltages，a novel computational method is proposed for public connection points in distribution networks. Based on the definition of an ideal load and the fundamental concept of load-current decomposition specified in German standard DIN 40110-2，the equivalent unbalanced conductance and lumped parameters of the load are first calculated. By exploiting the superior negative-sequence frequency selectivity of the fractional-order structural algorithm，the reactive unbalanced current component is extracted from the quadrature currents，enabling the separation and accurate calculation of the load unbalanced current even when the supply voltage is asymmetrical. Experimental results demonstrate that the proposed technique achieves accurate real-time calculation of load unbalance currents under unbalanced grid-side voltages directly in the time domain.