由于零序分量的存在,三相四线制电路的不平衡补偿问题较三相三线制电路更复杂。该文基于Steinmetz理论的对称分量分析法考虑三相三线制系统负荷的平衡化补偿思路给出了三相四线制系统负荷不平衡电流的补偿方法,并给出3种约束方程下的补偿电纳模型。在三相四线制系统中,在已找到的3种约束方程条件下,对Y型联接的负荷进行零、负序电流补偿,并使系统功率因数提高到1。最后通过Matlab仿真表明,所提补偿理论不仅能实现不平衡电流的平衡化,还能使系统总功率因数接近于1,证明了所提补偿理论的正确性。
Because of the existence of zero sequence components, the unbalanced compensation of three-phase four- wire system is more complicated than that of three-phase three-wire system. The compensation method of symmetrical component analysis method based on Steinmetz theory in three-phase three-wire system load balancing compensation is considered in the three-phase four-wire system unbalanced load current compensation. Moreover, the compensation model of three kinds of constraint equations is given. In the three-phase four-wire system with the three above constraint equations, attempts are made to compensate the zero sequence and negative sequence current for star-connected load, and increase the system power factor to 1. Finally, the Matlab simulation results show that the proposed compensation theory can not only keep the unbalanced current balanced, but also make the power factor of total system be equal to 1 approximately, which proves the correctness of the proposed compensation theory.