Biblio

The modern power system is experiencing rapid development towards a smarter cyber-physical power grid. How to comprehensively and effectively identify the vulnerable components under various cyber attacks has attracted widespread interest and attention around the world. In this paper, a game-theoretical scheme is developed to analyze the vulnerabilities of transmission lines and cyber elements under locally coordinated cyber-physical attacks in a cyber-physical power infrastructure. A two-step scenario including resources allocation made by system defender in advance and subsequent coordinated cyber-physical attacks are designed elaborately. The designed scenario is modeled as a game of incomplete information, which is then converted into a bi-level mathematical programming problem. In the lower level model, the attacker aims at maximizing system losses by attacking some transmission lines. While in the higher level model, the defender allocates defensive resources, trying to maximally reduce the losses considering the possible attacks. The payoffs of the game are calculated by leveraging a strategy of searching accident chains caused by cascading failure analyzed in this paper. A particle swarm optimization algorithm is applied to solve the proposed nonlinear bi-level programming model, and the case studies on a 34-bus system are conducted to verify the effectiveness of the proposed scheme.

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.