Hybrid genetic approaches to ramping rate constrained dynamic economic dispatch

Hybrid genetic algorithms (HGAs) are proposed in this paper to determine the economic scheduling of electric power generation over a fixed time period under various system and operational constraints. The proposed technique can outperform conventional genetic algorithms (CGAs) in the sense in that HGAs make it possible to improve both the quality of the solution and reduce the computing expenses. In contrast, any carefully designed GA is only able to balance the exploration and the exploitation of the search effort, which means that an increase in the accuracy of a solution can only come at the sacrifice of convergent speed, and vice visa. It is unlikely that both of them can be improved simultaneously. The proposed hybrid scheme is developed in such a way that a simple GA is acting as a base level search, which makes a quick decision to direct the search towards the optimal region, and a local search method (gradient search technique) is next employed to do the fine tuning. The aim of the strategy is to achieve the cost reduction within a reasonable computing time. The effectiveness of the proposed hybrid technique is verified on a real public electricity supply system with 25 generator units. The simulation results obtained with the HGAs for the real system are very encouraging with regard to the computational expenses and the cost reduction of power generation. (C) 1997 Elsevier Science S.A.