Three-phase harmonic load flow method

In this paper, a fast harmonic load flow method is proposed for unbalanced radial distribution systems. The proposed method is developed from the commonly used current-injection formulation and forward/backward sweep techniques. By the backward sweep technique, the relations between branch currents and the harmonic sources can be formulated, and then the harmonic voltage of each bus can be solved by the forward sweep technique. The proposed method is more efficient than the conventional harmonic load flow algorithms, since the time-consuming procedure of the Y matrix inverse is not required in the solution procedure. Some applications of the proposed method, such as the frequency scan of driving point impedance at the possible harmonic resonant buses, are also presented in the paper. Test results demonstrate the accuracy and efficiency of the proposed method.