Voltage Stability Toolbox (VST). Voltage instability and collapse have become an increasing concern in planning, operation, and control of electric power systems. In order to understand the phenomena and mechanics of voltage instability,a powerful and user-friendly analysis tool is very helpful. Voltage Stability Toolbox (VST) developed at the Center for Electric Power Engineering, Drexel University combines proven computational and analytical capabilities of bifurcation theory and symbolic mplementation and graphical representation capabilities of MATLAB and its Toolboxes. It can be used to analyze voltage stability problem and provide intuitive information for power system planning, operation, and contro