Distributed Fixed-Time Transient Stability Control Scheme for Power Systems With Heterogeneous Dynamics

To address the obstacles of frequency synchronization and phase angle cohesion caused by heterogeneity in generator dynamics, a distributed hierarchical fixed-time frequency control framework is devised in this paper to enhance transient stability. In the top interaction observer layer, a distributed homogeneous observer is designed for each follower generator to guarantee the follower's estimation states reach the expected leader's states based on Lyapunov and fixed-time theories. In the bottom local controller layer, based on fixed-time control and backstepping method, different controllers are constructed for follower generators with heterogeneous dynamics to make the follower's actual states track their estimation states. In addition, denial-of-service (DoS) attacks may block information transmission required by the distributed control and endanger system stability. The proposed distributed frequency control can be transformed into local frequency control to achieve self-defense against DoS attacks. According to direct feedback linearization, the nonlinear voltage control coordinated with the proposed distributed fixed-time frequency control is designed to enhance transient stability by imposing additional damping. Simulations confirm the efficiency of the proposed transient stability control scheme of power systems with heterogenous generator dynamics.