Using chaos search immune genetic and fuzzy system for short-term unit commitment algorithm

This paper presents a hybrid chaos search (CS) immune algorithm (IA)/genetic algorithm (GA) and fuzzy system (FS) method (CIGAFS) for solving short-term thermal generating unit commitment (UC) problems. The UC problem involves determining the start-up and shut-down schedules for generating units to meet the forecasted demand at the minimum cost. The commitment schedule must satisfy other constraints such as the generating limits per unit, reserve and individual units. First, we combined the IA and GA, then we added the chaos search and the fuzzy system approach. This hybrid system was then used to solve the UC problems. Numerical simulations were carried out using three cases: 10, 20 and 30 thermal unit power systems over a 24 h period. The produced schedule was compared with several other methods, such as dynamic programming (DP), Lagrangian relaxation (LR), standard genetic algorithm (SGA), traditional simulated annealing (TSA) and traditional Tabu search (TTS). A comparison with an IGA combined with the chaos search and FS was carried out. The results show that the chaos search and FS all make substantial contributions to the IGA. The result demonstrated the accuracy of the proposed CIGAFS approach. (C) 2005 Elsevier Ltd. All rights reserved.