Fault Tolerance and Security for Power Transmission System Configuration with FACTS Devices

One of the most promising decentralized network controllers is the family of power electronics-based controllers, known as “flexible AC transmission system” (FACTS) devices. These devices locally modify the topology of the system by rapid switching. By the choice of switching patterns, these devices can achieve a variety of power system objectives, such as voltage support, oscillation damping, and stability improvement. This ability can be used for not only reliability objectives such as increasing the maximum throughput power, but can also be used to adjust power flow for economic reasons. In the power system restructured environment, it is foreseeable that power flows will be adjusted throughout the system to maximize economic objectives. These devices, however, are relatively new and few are currently beyond the prototype stage, therefore their wide-spread impact on the transmission network has not yet been thoroughly analyzed. While these devices offer increased network power flow controllability, the decentralized nature of their actions may cause deleterious interactions between them. In this paper, we propose to utilize flexible topology FACTS devices in developing distributed control strategies to i) detect and mitigate intentional or unintentional cascading failures, ii) develop operating strategies that can automatically adjust to changing economic and physical environments, and iii) develop interaction policies to mitigate counterproductive actions.