Nonlinear model parameter analysis of ULFO in large-scale hydropower systems

3rd International Conference on Energy Engineering and Environmental Protection

能源学;生态环境科学

Zhang, Kunjun^1 ; Zhang, Jian^1 ; Wang, Guanhong^1 ; Li, Wenfeng^1 ; Gesang, Jinmei^2 ; Jie, Dang^3

China Electric Power Research Institute, Beijing

100192, China^1

State Grid Tibet Electric Power Co. Ltd, China^2

Technology Center of Central China Grid, China^3

关键词: Delivery systems;    Frequency oscillations;    Hydroelectric units;    Joint stabilities;    Large-scale hydropower systems;    Oscillation frequency;    Primary frequency regulation;    Ultra low frequencies;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/227/3/032042/pdf
DOI  :  10.1088/1755-1315/227/3/032042

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

The instability of the primary frequency regulation process of hydroelectric units has led to the occurrence of ultra-low frequency oscillations(ULFO) which frequency is less than 0.1 Hz.It mainly appears in the isolated power grid and direct current delivery system with high proportion of hydropower in recent years.So it is very important to study the influence of the main link parameters of the primary frequency regulation on ULFO including the water inertia time constant, system load frequency regulation coefficient. In this paper, a nonlinear model based on each link of primary frequency regulation process is built, and the oscillation frequency of the system under the influence of different parameters is determined by using a variety of frequency domain analysis methods. The influence of the main parameters on the frequency oscillation of the system is analyzed in detail, including the joint stability region which guarantees the stability of the system under the coupling of the governor parallel PID parameters.Nonlinear link is linearized by the method of description function.A new method to determine the parameter range of each link is proposed.