Power System Risk Assessment in Cyber Attacks Considering the Role of Protection Systems

This paper presents a risk assessment method for evaluating the cyber security of power systems considering the role of protection systems. This paper considers the impact of bus and transmission line protection systems located in substations on the cyber-physical performance of power systems. The proposed method simulates the physical response of power systems to malicious attacks on protection system settings and parameters. The relationship among settings of protection devices, protection logics, and circuit breaker logics is analyzed. The expected load curtailment (ELC) index is used in this paper to quantify potential system losses due to cyber attacks. The Monte Carlo simulation is applied to calculate ELC for assessing attackers' capabilities as bus arrangements are altered. The effectiveness of the proposed risk assessment method is demonstrated using a 9-bus system and the IEEE 68-bus system.