Fuzzy mixed integer programming: Approach to security-constrained unit commitment

This paper presents a formulation of fuzzy mixed integer programming (FMIP) solution for solving security-constrained unit commitment (SCUC) problem with emphasis on uncertainties in forecasted parameters in constraints. The proposed approach could be used by vertically integrated utilities as well as the ISOs in restructured power system. In this model, uncertainties in forecasted load demand, ancillary services and wind power are simulated in a fuzzy frame. Problem is finding a solution which satisfies the constraints and the objective with the maximum degree. The objective function will optimize while constraints have varying degree. The proposed model can be solved using a standard mixed integer-programming (MIP) solver. Case studies with the eight-bus system are presented in detail in this paper. We study the impact of uncertainty in forecasted parameters in SCUC solution and compare the results with those of crisp SCUC model.