Three-Phase Power Flow Calculation Method for Radial Distribution Networks

Three-phase power flow calculation methods for radial distribution networks play a critical role in power system analysis. This paper conducts a comparative analysis of common distribution network power flow calculation approaches, with particular emphasis on explaining the fundamental principles of the forward-backward sweep method. The forward-backward sweep algorithm has become one of the mainstream methods for distribution network power flow calculation due to its computational efficiency and suitability for radial network structures. The algorithm implementation typically involves iteratively solving branch currents in the forward sweep and node voltages in the backward sweep until convergence criteria are met. For practical systems containing weakly meshed network structures, this paper proposes corresponding processing methods and verifies the algorithm's effectiveness through simulation examples. The implementation handles weakly meshed networks by implementing loop-breaking techniques and compensation current calculations. Furthermore, with the widespread integration of distributed generation, the paper discusses in detail the mathematical models of different distributed energy resources (such as PQ, PV, and PI nodes) in power flow calculations, with special focus on analyzing processing strategies for PV nodes. The algorithm incorporates appropriate node type handling routines to ensure adaptability to various distributed generation integration scenarios. PV nodes require special voltage regulation mechanisms and reactive power limit checks in the computational process. Finally, simulation tests on a 33-bus system validate the accuracy and applicability of the proposed method in three-phase power flow calculations containing distributed generation. The results demonstrate that this method can effectively solve power flow calculation problems in radial distribution networks and provide reliable theoretical support for future smart distribution network analysis and planning. The implementation architecture includes modular components for network data processing, iterative computation loops, and convergence monitoring functions.