Harmonic Distortion Mitigation in Unbalanced Distribution Systems by NSGAII optimization

This paper presents a methodology for passive filter allocation within an electrical unbalanced distribution system aiming to reduce system harmonic distortion. Harmonic distortions are usually eliminated using filters, however, their allocation in the system requires attention. An inadequate allocation of filters might harm Power Quality (PQ) and can increase harmonic distortion at other buses by harmonic flow changes. We consider that filters are single-phase. The methodology is based on modeling and simulation on Alternative Transient Program (ATP/EMTP) and Matrix Laboratory (MATLAB) where the indices of harmonic distortions are verified. Different scenarios are generated through the Non-Dominated Sorting Genetic Algorithm II (NSGAII), then using an automatic simulator, all them run on ATP while MATLAB evaluates each one through multi-objective function. The problem is composed by two objectives, they are conflicting, one aims to decrease the harmonic distortion and the other to reduce the filters cost. The results show that the use of single-phase passive filters is a viable solution when the system is unbalanced and polluted by harmonic distortion.