Three-phase power-flow by direct ZBR method for unbalanced radial distribution systems

This paper introduces a novel three-phase power flow approach for unbalanced radial distribution systems. The proposed approach is developed based on the branch frame of reference, rather than the traditional bus frame of reference. On the basis of the branch frame of reference, a simple direct iterative method can be applied. Hence, the proposed approach may be called the 'direct ZBR method'. Basic graph theory and injection current technique are also applied in the proposed approach. The clear theoretical foundation and the simple topology of the radial distribution network make the proposed method efficient and reliable. To demonstrate the better convergence performance and the efficiency of the proposed approach, four three-phase IEEE test feeders are used for comparisons. The test results show that the proposed method has robust convergence characteristics and high performance, especially for large-scale radial distribution systems.