Passive harmonic filter planning considering daily load variations and distribution system reconfiguration

Abstract

Although distribution system reconfiguration is usually implemented for grid loss reduction, it can affect many other indices of the grid such as voltage profile and power quality indices. Therefore, harmonic filter planning studies which ignore different configurations of the system cannot achieve optimal solutions. In other words, when the filter planning study is carried out with respect to a single grid topology, power quality constraints satisfaction isn’t guaranteed while the real-world loss-reduction-based reconfigurations are applied to the system. In order to incorporate different configurations of the grid in planning study, this paper proposes an aggregate model for passive harmonic filter planning and loss-reduction-based reconfigurations in primary distribution systems. In this method, in order to incorporate distribution system operator decisions, reconfiguration for loss minimization is carried out as a lower level problem in pre-determined hours of each day type. The passive harmonic filter planning (as the higher level problem) is then studied with respect to the daily load profiles and different system configurations. Two separate Genetic-Algorithm (GA) cores are implemented to solve the main passive harmonic filter planning problem and reconfigurations. The proposed method is then applied to a modified 33-bus system with high penetration of nonlinear loads. The simulation results verified that ignoring the system reconfigurations in planning process may result in power quality constraints violation in some specified hours during the planning horizon. On the other hand, incorporating different system topologies in the planning study guarantees to maintain the system Total Harmonic Distortion (THD) levels within the standard limits and results in lower energy loss, capacity occupation and filter investment cost.