A PSO-Based Fuzzy Long-Term Multi-Objective Optimization Approach for Placement and Parameter Setting of UPFC

This paper presents a Particle Swarm Optimization (PSO)-based fuzzy multi-objective methodology for optimal locating and parameter setting of Unified Power Flow Controller (UPFC) in a power system for a long-term period. One of the profits obtained by UPFC placement in a transmission network is the reduction in total generation cost due to its ability to change the power flow pattern in the network. Considering this ability, UPFC can be also used to remove or at least mitigate the congestion in transmission networks. The other issue in a power system is voltage violation which could even render the optimal power flow problem infeasible to be solved. Voltage violation could be also mitigated by proper application of UPFC in a transmission system. These objectives are considered simultaneously in a unified objective function for the proposed optimization algorithm. At first, these objectives are fuzzified and designed to be comparable against each other and then they are integrated and introduced to a PSO Algorithm to find the solution which maximizes the value of integrated objective function in a 3-year planning horizon, considering the load growth. A power injection model is adopted for UPFC. Unlike the most previous works in this field the parameters of UPFC are set for each load level to avoid inconvenient rejection of more optimal solutions. IEEE Reliability Test System is used as an illustrative example to show the effectiveness of the proposed method.