An Efficient Load Flow Algorithm for AC–DC Distribution Systems

Abstract

The AC–DC distribution systems have recently gained huge popularity due to advancements in power converters, high penetration of renewable energy resources and widespread use of DC loads. However, load flow in such systems is a challenging task, due to non-linear characteristics of power converters. This paper presents a new and computationally efficient load flow algorithm for AC distribution systems using graphical search technique along with matrix algebra and has been further extended for solving AC–DC distribution systems load flow problem by making use of proposed per-unit equivalent model of various power converter devices. In contrast with traditional methods, the proposed technique does not require any LU decomposition, matrix inversion and forward backward substitution of admittance matrix or Jacobian matrix. The significant feature of the proposed algorithm lies in formulation of path impedance matrix and loads beyond branch matrix, which will remain unaltered for the entire operation. Reconfiguration of these matrices takes place automatically in accordance with the change in input data. Because of the aforementioned reasons, the developed technique is computationally potent when applied on large sized distribution systems. The proposed method has been validated on various standard test systems. Results show feasibility and authenticity of the proposed method.