Unit commitment is one of the serious major problems encountered in power system operation, control and coordination. It is a complex non-linear problem used in the schedule of operation of generating units at minimum operating cost. This paper presents a new formulation and classical exhaustive enumeration search method for the well-known unit commitment problem for scheduling thermal and hydroelectric power generating units in a day-ahead electricity market. In the study, the two objective functions formulated are minimisation of total production cost and maximisation of the energy consumption. To effectively deal with the constraints of the problem, the difficult minimum up/down-time constraints of thermal generation units and the turbine operating constraint of hydropower stations are embedded in the binary strings that are coded to represent the on/off-states of the generating units. The Nigeria 330?kV power system containing four thermal and three hydropower plants is studied under different scenarios for a 24?h horizon to show the effectiveness of the proposed algorithm. Although the approach is not really computationally efficient compared to some methods, a high accuracy of optimal solution is guaranteed. The results obtained in the study are compared with the ones reported in the literature, which confirm the effectiveness of the proposed technique.
展开▼
