The search for an on-line dynamic security index

The implementation of a power system dynamic security index (DSI) for contingency selection in an online dynamic security analysis environment is addressed. This DSI is based on a stochastic measure of the power system´s stability in the presence of various disturbances. This stochastic measure is the mean first passage time (MFPT) of a power system to reach the boundary of its dynamic security region. In other words, the MFPT is a measure of the average time a power system will eventually take to reach its dynamic security limits when affected by a contingency. One of the main advantages of the application of such a measure is the incorporation of not only the dynamic effects but also the steady-state effects of various power system disturbances