抄録
A new method has been developed for thermal and pumped-storage hydro unit commitment, which can prepare the optimized schedules with higher security and lower operation cost. The method of thermal unit commitment consists of three steps. (1)The optimal priority order of each unit is prepared based on the ratio of fuel to power cost as a function of incremental fuel cost λ. (2)The solution candidates are selected by fixing higher priority units as must-on and lower priority as must-off, and by searching middle priority units as “search window” to satisfy the constraints depending on the interval such as spinning reserve and load flow. (3)Based on the above-selected candidates, the optimal schedule is determined by dynamic programming, which satisfies the constraints extended over the whole time intervals such as crew constraints. The hydro schedule is decided as a substitute for the peak thermal units of lower efficiency so as to further reduce the total operation cost.
The effectiveness of present method has been demonstrated by application to test problems for a real power system with 53 thermal and 3 pumped-storage hydro units, in which the present method can reduce the operation costs by 0.20%-0.43% compared to the conventional priority order method.
