三相四线低压配电系统电流不平衡问题分析

Research on Current Imbalance in Three-phase Four-wire Low-voltage Distribution System

针对三相四线低压配电系统中性线完好而负载不平衡情况进行了分析,通过无功补偿的方法控制中性线电流为0,控制三相电流平衡.给出了判断补偿相的方法,建立了计算相应相与中性线间电流、相线补偿容量、线间电流、线间补偿容量等数据的数学模型.通过对实际系统的仿真计算表明,按照该方法进行无功补偿,可使中性线电流接近0,且相电流对称,优化了负荷的运行条件.

The problem that neutral wire is in good condition while load is unbalanced in three-phase four-wire system low-voltage distribution system is analyzed in this paper. Through making the current of the neutral wire to be zero and balancing three-phase current, a method judging compensation phase is given. Furthermore, a mathematic model of calculating phase current, phase compensation capacity, line-to-line current and line-to-line compensation capacity are built. The simulation results of the actual system show the reactive-load compensation using the method in this paper can make the neutral line current close to zero, phase current symmetric, and the load operating conditions optimized.