Decomposition approach to unit commitment with reactive constraints

Abstract

The authors propose an efficient algorithm for considering reactive power and voltage constraints in unit commitment. The inclusion of these reactive constraints in unit commitment will ensure enough commitment of real power and a feasible distribution of reactive power in power systems. Because the problem is a large mixed-integer programming and has a two-level hierarchical structure, the Benders decomposition method is used. Using decomposition, the master problem solves unit commitment and the subproblem examines reactive power and voltage constraints every hour to test the feasibility of the unit commitment solution. In the case of infeasibility, a proper constraint (Benders cut) is introduced and placed in the master problem for rescheduling the units. The iterative process provides a minimum cost solution for generation scheduling while satisfying reactive constraints. Test examples on the modified IEEE 30 bus system are presented to demonstrate the efficiency of the method.