Convergence problem in forward/backward sweep power flow method caused by non-positive-sequence impedance of distributed generators and its solution

A variety of distributed generators (DGs) are integrated in distribution system which is usually operated under three-phase unbalanced conditions. The zero and negative sequence impedances of DGs may vary within a large range. In this paper, the convergence problem caused by the zero and negative sequence impedances of DGs in forward/backward sweep three-phase power flow is found through numerical experiments. The reason of this phenomenon is explained and an impedance compensation method is proposed to solve this problem.