Multiple-frequency three-phase load flow for harmonic analysis

A multiple-frequency three-phase load-flow model was developed in this paper. There are two new submodels including the fundamental power flow (FPF) and harmonic frequency power-flow (HPF) model. In FPF, models of electrical elements and PV buses were treated in the form of current injections in a transmission system. The standard Fourier analysis was used to deal with the harmonic loads to get injection currents. With harmonic currents as equivalent current sources, the HPF can be derived. Besides, the decoupled fast version of FPF and HPF, called DFPF and DHPF, were also proposed in this paper. Test results show that the proposed general-purpose methods are better performers than conventional power-flow solutions and are very robust.