FDM based multi-objective optimal sitting and design of TC-FLSFCL for study of distribution system reliability

Abstract

An approach for optimal placement of flux-lock type SFCL with tap changer (TC-FLSFCL) and adjustment of tap changer related to it is used in this paper by debating the reduction of fault current and enhancement of reliability in a distribution network connected with distributed generation (DG). Recently, various superconducting fault current limiters (SFCL) have been developed in the field of power system. Especially, through researches, SFCLs have been put to practical use in distribution network as well as in the transmission network. TC-FLSFCL is a flexible SFCL that it has some preference than previous SFCLs. In this type of SFCL the current limiting characteristics are improved and the fault current limiting level during a fault period can be adjusted by controlling the current in the third winding, which also made the magnetic field applied to the high-Tc superconducting (HTSC) element. Three objective functions based on reliability index, reduction of fault current and the number of installed TC-FLSFCL are systematized and a nonlinear time-varying evolution (NTVE) based multi-objective particle swarm optimization (MOPSO) style is then formed in searching for the best location and tuning of tap changer of TC-FLSFCL to meet the fitness requirements. A decision-making procedure based on fuzzy decision making (FDM) is used for finding the best compromise solution from the set of Pareto-solutions obtained through MOPSO-NTVE. In a distribution network, Bus 4 of Roy Billinton test system (RBTS), comparative analysis of the results obtained from application of the resistive SFCL (RSFCL) and TC-FLSFCL is presented. The results show that optimal placement of TC-FLSFCL than RSFCL can improve reliability index and fault current reduction index with less number.