Convergence of the backward/forward sweep method for the load-flow analysis of radial distribution systems

This paper presents a study on the convergence characteristics of the backward/forward sweep method, which is one of the most effective methods for the load-flow analysis of the radial distribution systems. After revisiting the theoretical background, the convergence conditions and the evolution of the iterative process are investigated in detail for different load models. A dedicated study of the properties of the backward/forward sweep method is performed, taking into account different line X/R ratios and different types of voltage-dependent loads. Some useful indicators are introduced to estimate the number of iterations required to reach the convergence of the iterative process under a given tolerance. Test results are included for a tutorial twonode system and for a real 84-node system.