Biblio

Modern power systems heavily rely on the associated cyber network, and cyber attacks against the control network may cause undesired consequences such as load shedding, equipment damage, and so forth. The behaviors of the attackers can be random, thus it is crucial to develop novel methods to evaluate the adequacy of the power system under probabilistic cyber attacks. In this study, the external and internal cyber structures of the substation are introduced, and possible attack paths against the breakers are analyzed. The attack resources and vulnerability factors of the cyber network are discussed considering their impacts on the success probability of a cyber attack. A procedure integrating the reliability of physical components and the impact of cyber attacks against breakers are proposed considering the behaviors of the physical devices and attackers. Simulations are conducted based on the IEEE RTS79 system. The impact of the attack resources and attack attempt numbers are analyzed for attackers from different threats groups. It is concluded that implementing effective cyber security measures is crucial to the cyber-physical power grids.

As information and communication networks are highly interconnected with the power grid, cyber security of the supervisory control and data acquisition (SCADA) system has become a critical issue in the power system. By intruding into the SCADA system via the remote access points, the attackers are able to eavesdrop critical data and reconfigure devices to trip the system breakers. The cyber attacks are able to impact the reliability of the power system through the SCADA system. In this paper, six cyber attack scenarios in the SCADA system are considered. A Bayesian attack graph model is used to evaluate the probabilities of successful cyber attacks on the SCADA system, which will result in breaker trips. A forced outage rate (FOR) model is proposed considering the frequencies of successful attacks on the generators and transmission lines. With increased FOR values resulted from the cyber attacks, the loss of load probabilities (LOLP) in reliability test system 79 (RTS79) are estimated. The results of the simulations demonstrate that the power system becomes less reliable as the frequency of successful attacks increases.