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The expansion of the power network and integration of wind farms pose challenges in the short-circuit current (SCC) problem. Transmission switching performs better in both flexibility and effectiveness compared with other SCC restriction measures, while the power grid security would be threatened as the number of switched-off-lines increases. This paper proposes a day-ahead scheduling model considering commitment of units and N-1 criterion, to avoid the excessive SCC problem caused by wind farms integration. Specially, the SCC calculation model of the grid-connected wind farms is put forward to aggregate wind farms and calculate SCC. A novel SCC formulation considering transmission switching, commitment of units as well as wind farms integration is deduced and converted to SCC constraints. The SCC constrained mixed-integer linear programming (MILP) based day-ahead scheduling model is proposed, which minimizes system operation cost and transmission switching cost. In addition, the N-1 security requirement is considered in the proposed day-ahead scheduling model to ensure system security by avoiding switching off too many lines. Numerical results of a modified IEEE 30-bus system with two wind farms illustrate effectiveness of the proposed model.INDEX TERMS Short-circuit current, wind farm integration, transmission switching, day-ahead scheduling, mixed-integer linear programming NOMENCLATURE Major symbols and notations used throughout the paper are defined below, while others are defined following their first appearances as needed. Indices: l,g,wIndices of lines, thermal generating units and wind farms. t,n,c,dIndices of hours, buses, contingency statuses and loads. Variables: c g Marginal operation cost of unit g. c lOperation cost of switching line l. I g,t , I w,t

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