On Resilience and Distributed Fixed-Time Control of MTDC Systems Under DoS Attacks

This article investigates the resiliently distributed fixed-time control of frequency recovery and power allocation in a multi-terminal high voltage direct current (MTDC) system against denial-of-service (DoS) attacks. An MTDC system typically consists of several AC areas, on which the DoS attacks may cause communication faults by blocking communication channels, preventing certain AC areas from sending message and damaging related facilities. A novel distributed security control scheme is proposed in this paper, which introduces attack detection method and communication repair mechanism to restore the paralyzed topology caused by DoS attacks. By extension, a resiliently distributed fixed-time control is presented under this frame. The proposed control scheme can not only realize frequency restoration but also accomplish active power sharing under DoS attacks. Furthermore, different from existing control strategies, the advanced scheme can guarantee the convergence time without considering the initial value, which helps improve the robustness and stability of the MTDC system. The resilient stability of the proposed scheme is proved by Lyapunov-Krasovskii stability theory. Finally, case studies on an MTDC system are conducted to demonstrate the effectiveness and validity of the proposed controller. Note to Practitioners - MTDC system is a large-scale power system connecting various AC grids. It has the characteristics of distributed and high intelligence, which is prone to be attacked by an adversary. As an index to measure the safe and stable operation of MTDC system, frequency is the focus of this paper. We propose a novel topology recovery mechanism for MTDC systems under DoS attack and design a resilient fixed-time secondary frequency controller based on the idea of multi-agent. The experimental results show that under DOS attack, the proposed topology recovery mechanism and controller can recover the frequency to the rated value in a fixed time and realize the proportional distribution of active power. In practical application, engineers can learn from the controller to resist DoS attack and realize the stable operation of large-scale distributed power system.