Probabilistic multi-objective generation and transmission expansion planning problem using normal boundary intersection

This study presents a model of coordinated generation and transmission expansion planning (TEP). The proposed model simultaneously minimises total cost, including planning and total fuel cost, environmental impact in terms of SO₂ and NO_x emission and fuel price risk while maximising the system reliability. Owing to intermittent behaviour of loads and fuel prices, the expansion planning problem should be analysed using probabilistic approaches instead of deterministic ones. Therefore, a new approach is proposed to solve the multi-objective probabilistic coordinated generation and TEP problem. The point estimate method is used to take into account the effect of uncertainty in fuel prices and system demand. The normal boundary intersection (NBI) method is used to obtain the Pareto-optimal solutions. Moreover, fuzzy decision-making process is employed to select one of the Pareto-optimal solutions as the most preferred solution. The proposed model is implemented on the modified Garver6-bus system to evaluate its efficiency. Finally, the results of the NBI method are compared with the classical weighted sum method. Additionally, the model is implemented on the IEEE 24-bus reliability test system, and the results are compared with the virtual database-supported non-dominated sorting genetic algorithm II (VDS-NSGA II) and NSGA II methods.