Research on Reactive Power Planning for Power Grid with the Integration of UHV AC System

URV AC transmission has the characteristics of large capacity, long distance, low loss and effective utilization of transmission corridor. It is an inevitable choice for the development of power grid in China. The operation of UHV AC system will have a considerable impact on the operation economy and stability of power grid, and also put forward new requirements for reactive power planning. In this paper, a two-stage reactive power planning model is proposed, in which the first-stage reactive power planning model aims at the minimization of system operation cost, active power loss and traversing reactive power under normal conditions. The second-stage model is to obtain the optimal reactive power planning scheme with the goal of minimizing the investment cost and the constraint of voltage stability margin under severe faults based on the first-stage planning scheme. Finally, the effectiveness of this model is verified through numerical results.