Mixed Integer Linear Programming Model for Monthly Unit Commitment in the National Level Power System

In electrical power system, unit commitment is a fundamental problem for power system planning which aims to maintain electricity production continuously and respond the electricity consumption during every time interval of the scheduling horizon. For long-term operational planning, monthly unit commitment is especially concerned to optimally implement due to the adequate fuel provision for the available generating units over a month. In this study, optimizing the commitment with fuel limitation, daily peak load demand, and operational conditions for a month is considered. Accordingly, a mixed integer linear programming model is proposed with objective to ensure a sufficiency of fuel for the whole month, satisfying the total energy and covering the daily peak load demand with respecting to many operational constraints. The model is applied to a national level planning in Thailand power system which consists of various generator types including thermal, single-shaft gas turbine (SSGT), hydropower, combined-cycle-system gas turbine (CCGT), combined-cyclesystem steam turbine (CCST), and imported power which are purchased and supplied abroad. Simultaneously, development planning is examined and analyzed to reveal a generating unit status, producing output of each generator and fuel usage. Regarding the results, the decision makers can practically execute for scenario analysis of a variety of demand and fuel availability.