  In this paper, we investigate the feasibility and physical consequences of
cyber attacks against energy management systems (EMS). Within this framework,
we have designed a complete simulation platform to emulate realistic EMS
operations: it includes state estimation (SE), real-time contingency analysis
(RTCA), and security constrained economic dispatch (SCED). This software
platform allowed us to achieve two main objectives: 1) to study the cyber
vulnerabilities of an EMS and understand their consequences on the system, and
2) to formulate and implement countermeasures against cyber-attacks exploiting
these vulnerabilities. Our results show that the false data injection attacks
against state estimation described in the literature do not easily cause
base-case overflows because of the conservatism introduced by RTCA. For a
successful attack, a more sophisticated model that includes all of the EMS
blocks is needed; even in this scenario, only post-contingency violations can
be achieved. Nonetheless, we propose several countermeasures that can detect
changes due to cyber-attacks and limit their impact on the system.
