This article presents a novel global centralized-hierarchical emergency control system of large-scale power system based on online transient stability calculation. The system is composed of an upper-layer automatical predecision control system, the middle-layer regional stability control systems, and the bottom-layer executing devices. The upper-layer system can periodically evaluate the stability of the power system against contingencies and calculate emergency control scheme lists online with a high degree of accuracy. When middle-layer regional stability control systems detect a serious fault, the bottom-layer executing devices can prevent wide-area power system outage by instantly taking remedial action according to the emergency control scheme, which has been calculated in advance by the upper-layer system. Using system identification-based fast stability prediction algorithm and hybrid stability algorithm, the upper-layer predecision control system can perform the online stability assessment in less than 10 minutes. So the emergency control system can keep pace with various operation conditions, considerably enhancing the stability of the power system.
