A Three-Phase Unbalanced Linear Power Flow Solution With PV Bus and ZIP Load

With the penetration of distributed generators (DGs) into active distribution network (ADN), the voltage controlled buses (PV buses) are becoming more common, to maintain a normal voltage level in the distribution network. Moreover, there are many load modes in ADN which need to be taken into account. In this paper, the approximations of three-phase line model have been analyzed and the ZIP loads with star and delta connections were discussed in detail. And then based on the basic three-phase power flow equations, a general three-phase LPF solution under a polar coordinate system has been presented. The proposed method can account for various connections of ZIP loads, multi-phase feeders and single-phase or three-phase DGs. The effectiveness and advantages of the proposed method are validated with the IEEE 13-bus, 37-bus, 123-bus and an improved 615-bus unbalanced networks.