NOMENCLATURE

Abstract—This paper presents a new solution to the thermal unit-commitment (UC) problem based on an integer-coded genetic algorithm (GA). The GA chromosome consists of a sequence of al-ternating sign integer numbers representing the sequence of opera-tion/reservation times of the generating units. The proposed coding achieves significant chromosome size reduction compared to the usual binary coding. As a result, algorithm robustness and execu-tion time are improved. In addition, generating unit minimum up and minimum downtime constraints are directly coded in the chro-mosome, thus avoiding the use of many penalty functions that usu-ally distort the search space. Test results with systems of up to 100 units and 24-h scheduling horizon are presented. Index Terms—Generation scheduling, genetic algorithm, unit commitment