Optimal Allocation and Sizing of Fault Current Limiters Considering Transmission Switching With an Explicit Short Circuit Current Formulation

Abstract

As the power system expands with a more complex network structure, the excessive short-circuit current (SCC) has become a major obstacle to the rapid development of power system. The paper proposes a SCC-constrained planning model to determine the optimal locations and sizes of fault current limiters (FCLs) while considering transmission switching. N-1 security criterion is included to ensure that switching off lines will not jeopardize system security. One challenge is that the relationship between SCC and binary variables associated with switching states of transmission lines and activation statuses of FCLs is nonlinear and hard to obtain the exact expression. To this end, the paper begins with the equations of admittance matrix and nodal self-impedance, and derives the explicit formulation of SCC considering transmission switching and FCL activation. Based on the explicit expression of SCC, the proposed optimal allocation and sizing model of FCLs is formulated as a mixed integer linear programming (MILP) problem which could be solved by off-the-shelf commercial solver Gurobi in MATLAB. Numerical case studies on IEEE 30-bus, 118-bus and 1354-bus systems validate the effectiveness and advantages of the proposed model in reducing total costs and enhancing system security. The modeling accuracy of the explicit SCC formulation is also illustrated.