Abstract: Short-Term Hydrothermal Scheduling (STHS) is a nonlinear, multi-constrained and time-varying optimization problem. When the valve point effect is considered, the problem becomes non- convex and more complicated. In order to improve the search ability of the Krill Herd Algorithm (KHA) in the STHS problem, the hybrid chaotic map is introduced to improve the global convergence speed of KHA. In order to avoid premature convergence of the algorithm, by recording the number of times that the fuel cost values of the best individual in each generation remain unchanged and making the decision that a positional mutation in the non-positionally dominant individual within its feasible domain, a hybrid chaotic krill herd algorithm (HCKHA) is proposed. HCKHA and KHA, CKHA were applied to the standard STHS test systems such as "four hydro and three thermal plants" and "four hydro and ten thermal plants", independently. The simulation results show that HCKHA has better optimization ability, fuel cost values and transmission loss values than KHA, CKHA and the optimization methods in other related literatures.

Key words: short-term hydrothermal scheduling, hybrid chaotic krill herd algorithm, valve point effect, transmission loss