Coordinated reactive power planning against power system voltage instability

This paper implements a long term VAR planning algorithm developed earlier, which coordinates between network investments that most effectively address steady-state voltage instability and those which most effectively address transient voltage dip problems under severe contingencies. The algorithm is applied on a portion of a large scale system consisting of 16173 buses representing the eastern interconnection. The planning method is a mixed integer programming (MIP) based optimization algorithm that uses sensitivity information of performance measures with respect to reactive devices to plan for multiple contingencies simultaneously, while satisfying post-contingency voltage stability margin and transient voltage dip performance criteria. The study also takes account of induction motor dynamic characteristics, known to influence transient voltage recovery phenomenon. The results illustrate the effectiveness of the planning method when applied on a practical large scale system.