Steady state stability assessment using the bus impedance matrix

Power systems operations are undergoing changes, brought about primarily due to deregulation. Restructuring and interconnection of bulk power systems have made power system analysis much different than what it was earlier. All this, coupled with economic pressures, has made the present day power system an increasingly complex network, operating under stressed conditions, close to stability limits. Thus for present day power systems, voltage stability analysis has acquired predominant importance. This paper presents results of a method developed to assess the state of a system, from the viewpoint of voltage stability, after a certain load increase. Its unique feature is that it does not use any load-flow calculation at all. The concept of maximum power transfer at a node is used. This makes the method highly efficient in terms of computation time. Results are obtained for five test systems, and a comparison with the load flow calculations is presented.