  Ensuring reliable operation of large power systems subjected to multiple
outages is a challenging task because of the combinatorial nature of the
problem. Traditional approaches for security assessment are often limited by
their scope and/or speed, resulting in missing of critical contingencies that
could lead to cascading failures. This paper proposes a two-component
methodology to enhance power system security. The first component combines an
efficient algorithm to detect cut-set saturation (called the feasibility test
(FT) algorithm) with real-time contingency analysis (RTCA) to create an
integrated corrective action (iCA), whose goal is to secure the system against
cut-set saturation as well as critical branch overloads. The second component
only employs the results of the FT to create a relaxed corrective action (rCA)
to secure the system against post-contingency cut-set saturation. The first
component is more comprehensive, but the latter is computationally more
efficient. The effectiveness of the two components is evaluated based upon the
number of cascade triggering contingencies alleviated, and the computation
time. The results obtained by analyzing different case-studies on the IEEE
118-bus and 2000-bus synthetic Texas systems indicate that the proposed
two-component methodology successfully enhances the scope and speed of power
system security assessment during multiple outages.

Systems and Control;Systems and Control