Security of Fully Distributed Power System State Estimation: Detection and Mitigation of Data Integrity Attacks

State estimation (SE) plays an essential role in the monitoring and supervision of power systems. In today´s power systems, SE is typically done in a centralized or in a hierarchical way, but as power systems will be increasingly interconnected in the future smart grid, distributed SE will become an important alternative to centralized and hierarchical solutions. As the future smart grid may rely on distributed SE, it is essential to understand the potential vulnerabilities that distributed SE may have. In this paper, we show that an attacker that compromises the communication infrastructure of a single control center in an interconnected power system can successfully perform a denial-of-service attack against state-of-the-art distributed SE, and consequently, it can blind the system operators of every region. As a solution to mitigate such a denial-of-service attack, we propose a fully distributed algorithm for attack detection. Furthermore, we propose a fully distributed algorithm that identifies the most likely attack location based on the individual regions´ beliefs about the attack location, isolates the identified region, and then reruns the distributed SE. We validate the proposed algorithms on the IEEE 118 bus benchmark power system.