Reliability constrained coordination of generation and transmission expansion planning in power systems using mixed integer programming

This paper presents a new approach on expansion planning problem in power systems. The simultaneous expansion of generation and transmission subsystems has been formulated as a mixed integer programming problem to cover different constraints. The method introduces a static planning method which models the least cost deviation from the initial point (pre-expansion condition) in a manner that matches the peak load requirements of the planning horizon (post-expansion condition). The DC power flow model is used to reflect transmission flow constraint in a framework that automatically eliminates disconnected bus problem. Instead of considering just one candidate design for a corridor, different types of designs have been included in the model. This fact makes the model more practical in the transmission expansion planning section. Environmental constraints and fuel supply limitations have been also included for thermal units. Besides, a heuristic algorithm has been proposed to assure the required amount of reliability at hierarchical level II. The algorithm is based on reinforcing the economically optimal plan to upgrade its reliability level to any desired value. The scheme is capable of suggesting an economical level of reliability for a given system by reflecting cost and worth of reinforcements. To numerically evaluate the efficiency of the proposed method, simulation results on the modified Garver6-bus and IEEE 30-bus systems are provided. In spite of huge computation burden at hierarchical level II (HLII) reliability assessment, the results indicate high efficiency of the proposed method.