中文摘要：

为实现分布式发电（distributed generation,DG）接入弱环网配电后潮流的有效计算,推导出一种基于回路分析法的三相弱环配电网潮流的改进算法。该算法利用配电网络的道路矩阵和回路矩阵,得到了节点电压、回路电流以及注入电流这3者之间的关联公式,从而使环网处理变简单。同时,在保持PV节点正序电压幅值恒定的前提下,推导一种求解PV节点无功功率增量计算的新方法,并可方便地引入到所提潮流算法中。6母线和69母线测试算例验证了该算法的正确性和良好的收敛性,算法有较强的处理回路的能力,迭代次数随着环的增多而减少,并能在无功功率没有越界的情况下保证PV节点有功功率和电压幅值为预设定值。

英文摘要：

In order to effectively calculate the power flow of weakly meshed distribution system with distributed generation （DG）, a three-phase power flow improved algorithm had been developed base on loop-analysis method. In the algorithm, the related formula among node voltages, loop currents and injection currents were derived with path matrix and loop matrix of the distribution network. Meanwhile, based on the assumption that the positive-sequence voltage magnitudes of PV nodes are invariable, a new method to calculate reactive power increments of PV nodes was derived in detail. And the method could be easily integrated into the proposed power flow algorithm. The results of the 6-bus and the 69-bus test systems verify the correctness and good convergence of the proposed power flow algorithm. The results also show that the algorithm has the strong ability to deal with meshed networks and the iterative times will decrease with more loops. Besides, considering that reactive power limits were not violated, the positive-sequence voltage magnitudes and active powers can be kept on their scheduled values.