A VAR Planning Method with Multiple Power Flow Conditions

Abstract

The goal of reactive power (VAR) planning is to find the minimum cost installation plan of new reactive power sources so that the system voltage is maintained within an acceptable level. The consideration of multiple contingency states, together with the discrete nature of VAR facilities, creates a large-scale nonlinear mixed-integer programming (MIP) problem.
To overcome the discrete nature of VAR facilities, an approximate method for MIP problem is employed, since the method is Linear Programming based and thus efficient for large-scale problems. To treat the multiple contingencies, a resource directive decomposition approach is used in the proposed algorithm. If the number of installed VAR sources is fixed, the overall problem can be decomposed into independent subproblems. Then subproblems are coordinated to give a VAR installation pattern in which installation cost becomes cheaper than before. The algorithm proposed is tested for a 135-node real size system and the results show the validity and effectiveness of the algorithm.