Study on power grid dynamic optimal allocation of reactive power capacity considering the economic loss of voltage sag

In the large-scale receiving systems, considering the actual power grid operation condition and load characteristic, this paper introduces the voltage sag as stability considerations object. Take STATCOM as an example, this paper evaluates voltage sag based on quality engineering theory, describing the economic loss caused by the voltage sag and takes it as a cost model of voltage instability. Single objective function model of reactive power optimization is put forward, includes variation of economic losses of voltage sag and cost of dynamic reactive power compensation devices. Finally, an actual power system of a certain area is chosen for simulation, and corresponding optimal solution is further gained. The result shows the optimum proposal is effective for ensuring the safe reliability of system and reducing the economic cost.