Contingency analysis for a large number of voltage stability studies

Accurate voltage stability contingency analysis requires the computation of voltage collapse points for each contingency. That requires a lot of computation and is not a practical solution to the problem. Power system security assessment is usually done with a short contingency list. This paper compares a few contingency ranking methods suitable for static voltage stability studies. The methods studied are reactive power losses, minimum singular value of load flow Jacobian matrix, voltage stability margin approximation by curve fitting technique and contingency clustering. Tests are made with an IEEE 118-bus network.