Harmonic filters planning of system for specially connected transformers using a PSO method with nonlinear time-varying evolution

This paper is used to investigate the harmonic filters planning of a power system with three-phase to two-phase specially connected transformers. A particle swarm optimization method with nonlinear time-varying evolution (PSO-NTVE) is employed in the planning of large-scale passive harmonic filters. The objective is to minimize the cost of the filter, the filters loss, the total harmonic distortion of currents and voltages at each bus simultaneously. The reactive power compensation and constraints of individual harmonics are also considered. Three design cases are compared to demonstrate the design results. The study results shows that the scheme type of three-phase to two-phase specially connected transformers have significant effects on the harmonic distribution. The phase B of VV connection scheme has reduced 3rd order harmonic distortion, the Scott and Le Blanc connection scheme batter than VV connection scheme for improved harmonic distortion, and the many typical passive filters structure batter than one typical filter. From the results of the illustrative examples, the feasibility of the PSO-NTVE to design an optimal passive harmonic filter is verified.