INTEGRATED AC TRANSMISSION NETWORK EXPANSION AND REACTIVE POWER PLANNING

An integrated technique for solving transmission network expansion planningconsidering the allocation of reactive power sources using an AC model is presented in this paper.Embedding reactive power management in TNEP is a challenging task since AC load flow maynot converge in absence of proper reactive power allocation. Usually transmission expansionplanning and reactive power planning are considered as two distinct problems, but in this paperboth problems are investigated concurrently. These two problems can be integrated because thereis an inherent interaction between transmission line capacity and reactive power sources. In powersystems, transferring reactive power may engage line capacity which requires more newtransmission lines, while allocating reactive power sources close to the load centers may preventthe addition of new transmission lines. On the other hand, if reactive power sources are notincluded, real power losses will increase considerably and thereby reduce transmission linecapacities. The main objective of this study is to show that both active and reactive power planningcan be handled simultaneously. This non-convex combinatorial optimization problem is solvedhere using a real genetic algorithm (RGA). Significant results through case studies of two testsystems show the advantages of the proposed integrated network planning.