A Hierarchical Control Scheme for Transient Stability Augmentation by Thyristor Controlled Braking Resistors

In this paper, a hierarchical control scheme for improving transient stability of power systems by thyristor controlled braking resistor is proposed. Based on three-level co- state prediction method of large-scale system principle, the control structure is organized into a two-layer controller. The lower layer is composed of decentralized local feedback controllers, each of which takes local feedback signal and controls its connected generator. In the upper layer a global controller is designed to enhance the effectiveness of decentralized local controllers. The global controller coordinates local controllers by generating remote feedback signals which ensuring the global optimal solution of the overall system transient performance. The proposed control scheme can guarantee fast and accurate control actions of local controllers when a power system is subjected to large disturbances. Simulation results show the effectiveness of the proposed control scheme.