Solving the multiobjective environmental/economic dispatch problem with prohibited operating zones using NSGA-II

A thermal or hydro generating unit may have prohibited operating zones due to physical limitations of power plant components caused, for example, by vibrations in a shaft bearing which are amplified in a certain operating region. In this case, the unit can only operate above or below the prohibited operating zone. The effect of prohibited operating zones on the multiobjective environmental/economic dispatch problem is investigated in this paper. The IEEE 30-bus system with transmission losses has been considered with prohibited operating zones and simulation performed using the elitist Nondominated Sorting Genetic Algorithm (NSGA-II) for two constraint handling methods, namely penalty parameterless and decoder-based approaches. Simulation results show that both methods can equally handle this particular scenario in the environmental/economic dispatch problem. Different number of prohibited operating zones was considered for the six generators in the system yielding discontinuous and non-convex non-dominated fronts.