Decentralized Expansion of Transmission Networks Incorporating Active Distribution Networks

The benefits of transmission-distribution interactions at boundary buses are gradually unlocked in a restructured power network. Since the roles of transmission system planner and distribution system planner have some similarities in maintaining the economy and security of their systems, the transmission and distribution systems should collaborate and coordinate with each other to determine the expansion scheme in a positive and active manner. To address this problem, this paper presents a decomposition based expansion method for hybrid transmission and distribution networks (HTDNs), which simultaneously optimizes the hourly generation schedule. The original centralized optimization problem is decomposed into a transmission expansion subproblem encompassing numbers of distribution expansion subproblems. A distributed solution technique is proposed to guarantee shared variable consistencies. Case studies carried out on a HTDN, denoted as T24D9, validate the effectiveness and high performance of the formulated expansion problem.