Vulnerability Assessment of Cascade Contingencies in Power Systems

The post-mortem analysis of several blackouts has shown that cascade phenomena are involved in many of them. So, it is important to evaluate the power system vulnerability in the scope of this kind of events. This paper proposes a methodology to classify cascade events based on both interrupted load under a blackout and the time required by the system operator to restore the power supply, as a vulnerability assessment. At the same time, the cascade contingencies' vulnerability of the system is based on Monte Carlo simulations and a probabilistic representation of the cascade behavior that includes generator and branches failures, unnecessary operation and hidden failures in protection devices, branch's sympathetic tripping, operator reaction and operative under frequency load shedding scheme. The proposed algorithm has been tested on the IEEE 118 nodes system. Copyright (C) 2011 Praise Worthy Prize S.r.l. - All rights reserved.