The occurrence mechanism and damping method of ultra‐low‐frequency oscillations

IET Renewable Power Generation

Tomislav Dragicevic¹  Gang Chen²  Peng Wang³  Baohong Li³  Tianqi Liu³  Qin Jiang³  Xiaoyan Han⁴ 

[1] Department of Electrical Engineering Technical University of Denmark Lyngby Denmark;Department of Power System Technology State Grid Sichuan Electric Power Research Institute Chengdu China;School of Electrical Engineering and Information Technology Sichuan University Chengdu China;State Grid Sichuan Electric Power Company Chengdu China;

关键词: Power system control;    Stability in control theory;    Hydraulic and pneumatic control equipment;    Control of electric power systems;   

DOI  :  10.1049/rpg2.12092

来源: DOAJ

【 摘 要 】

Abstract The ultra‐low‐frequency oscillation (ULFO) problem has reappeared in China recently. Although the hydraulic generator is supposed to have a strong connection to this problem, the conditions for ULFO appearance and detailed reasons are not clear yet. In order to clarify the occurrence mechanism of ULFO, this paper studies each important part of hydraulic generator system, including the governor, exciter and power system stabiliser (PSS). The weak connection is confirmed to have an important impact on the occurrence of the ULFO. Nevertheless, by studying each device's contribution to ULFO through the complex torque coefficient method, it is shown that the negative damping effect of the hydraulic governor will cause the instability in the ultra‐low‐frequency band, while the exciter and the PSS have little influence on ULFO. Additionally, the proportional–integral parameters of the hydraulic governor system are also studied to clarify their influence on ULFO based on the complex torque coefficient method. Based on the above analysis, two damping methods for ULFO suppression are finally proposed. To verify theory and damping methods, the simulations are implemented in PSCAD and PSASP software.

【 授权许可】

Unknown