Allocation and sizing of single tuned passive filters in three-phase distribution systems for power quality improvement

Abstract

This paper presents an optimization problem formulation for allocation and sizing of single tuned passive filters in power distribution systems with the objective of minimizing total harmonic distortion. Inequality constraints are considered to determine upper and lower bounds for power factor correction, tuned frequency, voltage unbalance factor, voltage magnitudes and harmonic distortion based on power quality standard limits. The optimization problem is solved using genetic algorithm in which the filters locations, their connection types and parameters for each phase of the system are determined. Simulations are carried out using three-phase unbalanced 33-bus and 69-bus distribution test feeders to demonstrate the viability and efficiency of the proposed formulation to obtain results with total harmonic distortion lower than 5%, voltage unbalance factor lower than 1%, power factor greater than 0.92 and voltage magnitudes between acceptable limits. The main contributions of this paper are the formulation considering multiple power quality indexes in three-phase unbalanced distribution systems, the possibility of the filters to be connected in Y or Δ to satisfy the objective function and the constraints of the optimization problem. Additionally, security constraints related to the operation of the capacitor banks of the filters are considered in this paper.