A fast method for the estimation of power system security margins to voltage collapse

摘要

This paper presents a simple, fast and reliable method for determining the distance in parameter (load) space from the system current operating point to the critical point for which voltage collapse occurs. Sensitivity analysis is used to drive the system from the base case operating point to the vicinity of the critical point along a predefined load increase direction. In case infeasible operating points are reached, a special load flow method with step size optimization is used so that relevant information can be obtained to restore the feasibility. Finally, the critical point is estimated from a certain number of load flow calculation results for different operating points in the vicinity of the critical point, by increasing the load along the predefined direction. The security margin to voltage collapse is obtained at a low computational cost.