Power System Reliability Analysis With Intrusion Tolerance in SCADA Systems.

By intruding on the substations and control center of the supervisory control and data acquisition system, trip commands can be sent to intelligent electronic devices that control the power system breakers. Reliability of the power system can be impacted through the cyberattacks. In this paper, a modified semi-Markov process (SMP) model is used to describe the procedures of normal and penetration attacks against the intrusion tolerant system. By modeling the transition probabilities between the SMP states and sojourn time of each SMP state, the mean times to compromise the normal and penetration attacks are calculated. With increased probabilities of breaker trips resulted from the cyberattacks, the loss of load probabilities are evaluated based on IEEE reliability test system 79. When the level of attack increases or the level of defense in the system decreases, the simulation results demonstrate that the power system becomes less reliable. [ABSTRACT FROM PUBLISHER]