Transmission network expansion planning based on coordinated economy and security

Transmission network expansion planning (TNEP) is a key component of power system planning. Two important aspects to be considered in TNEP are economy and security factors, which are always contradictory and affect the benefits of both investment and power demand side, so the balance between these two factors needs to be focused. In this paper, a TNEP model based on coordinated economy and security is proposed so as to reconcile these two contradictory factors. The objective function of proposed TNEP model is to minimize the annual synthetic cost of transmission system, which contains investment cost, operation cost, maintenance cost and load shedding cost. The annual synthetic cost of transmission system is calculated with multistep load model established by load clustering using improved K-means algorithm. Then, an improved niche genetic algorithm is utilized to solve the TNEP model and an optimal scheme is obtained. Furthermore, the applicability and effectiveness of proposed TNEP model and algorithm are verified by case study on IEEE 24-bus system.