Abstract

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. The study is aimed at using unit commitment in generation planning and operation in Nigeria for the best utilization of available energy resources to meet the varying load demand. In the study, the two objective functions formulated are minimization of total production cost and maximization 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 330kV power system containing four thermal and three hydropower plants is studied under different scenarios for a 24h 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 the 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.