Computation of voltage stability margins of distribution systems

A robust and efficient tool for computing the voltage stability margin of distribution systems is proposed in this paper. This margin corresponds to the distance from the current operating point to the maximum loading point in load parameter space along a predefined load increase direction. This tool is based on computing the voltage stability index of a two-bus equivalent circuit for predicting load increases and a specialized, robust Newtonpsilas load flow method. It may also be useful for evaluating the impacts of the insertion of distributed generation on the system operation and voltage stability conditions. The proposed methodology has shown to be suited for environments subjected to severe computation time constraints, such as distribution management systems.