Research on the Dynamic Frequency Characteristic of Large-scale Power Grid Considering the Action of Power System Splitting and Load Shedding

The dynamic frequency characteristic of power system is a significant index for power system operation, and research on the dynamic frequency characteristic of power system is the basis of many important design works such as the design of under frequency load shedding scheme. With the AC and DC ultra-high voltage (UHV) networking and the expanding of the scale of power grid, the economy of power system has been greatly improved, while the ability of resisting disturbance being weakened. Since the frequency deviation has great impact on many aspects of power system, it is of great urgency and necessity to analysis and control the dynamic frequency characteristic of large-scale power grid after disturbance. Based on the analysis of the dynamic frequency characteristic of large-scale power grid, this paper firstly studies the factors which influence the dynamic frequency characteristic of multi-machine power system, and the method of parameter aggregation of dynamic frequency characteristics. Secondly, this paper analyzes the effect of the action of power system splitting on power system dynamic frequency characteristic, and the adaptability of power system under frequency load shedding(UFLS) after the action of power system splitting. Finally, based on a regional power grid as the test case, the correctness and effectiveness of the proposed parameter aggregation method of power system dynamic frequency characteristic is verified by comparing the theoretical calculation value of the dynamic frequency characteristic after specific disturbance with the simulation result of power system simulation software under the same circumstance. On the basis of the previous researches, the foundation for the further study on optimization of under frequency load shedding scheme is proposed.