Three-phase harmonic load flow in frequency and time domains

A hybrid method in the time and frequency domains has been developed for the analysis of the harmonic distortion in power systems. This method is more complete than others reported in the literature and it allows both balanced and unbalanced systems to be considered. The linear elements of a network are modelled in the frequency domain while the nonlinear elements are modelled in the time domain, which permits consideration of all topologies and configurations. Acceleration techniques are used for finding the steady state in time-domain methods. Linear and nonlinear loads can be specified in terms of power by integrating a three-phase load-flow algorithm for the fundamental frequency with a hybrid algorithm for the harmonic interaction analysis. The proposed method tries to solve the present problems to study harmonic-distortion propagation in a power system. The integration of two complex and different algorithms is done here for the first time and offers great possibilities for power-systems analysis.