Study on Stability Analysis and Safety Control Measures of Power Grid in the UHV AC Project of Shandong–Hebei Loop Network

With the development of China's power system, UHV gradually forms an interconnected system. The 1000kV UHV loop network in Shandong-Hebei has been in closed-loop operation. 8 1000kV UHV substation are included, which will greatly change the operation characteristics, fault characteristics and section current boundary conditions of the whole North China power grid. After the N-2 fault in key 1000kV lines, the impact on the system is very serious. The system begins to have potential stability hazards, which will cause voltage collapse in Shandong in serious cases. In this paper, the transient model of North China power grid is established. Including main generators, lines, main transformers, high reactance, etc. The system stability after N-2 fault of key component is studied, and the operation and recovery characteristics of the system are obtained. According to different fault conditions, the corresponding measures are discussed from both qualitative and quantitative perspectives to ensure the restoration and stability of power grid. The process of power grid stability restoration after fault and measures are simulated. Then, different stability measures are comprehensively compared to provide a theoretical basis for power grid control strategy. The dispatching unit can formulate different safety and stability control strategies in advance according to different operation modes and different load flow to deal with sudden faults and stability problems.