T-S Fuzzy based Load Frequency Control of Multi-Area Power System with Hybrid Delays: Performance Analysis and Improvement

• Published in: IEEE transactions on fuzzy systems pp. 1 - 12
• Main Authors: Yuan, Zhe-Li, Zhang, Chuan-Ke, Shangguan, Xing-Chen, Fan, Yu-Long, He, Yong
• Format: Journal Article
• Language: English
• Published: IEEE 26.09.2024
• Subjects: Analytical models; Delays; Design methodology; Frequency control; Generators; hybrid delays; Hybrid power systems; Load frequency control; Performance analysis; Power system stability; robust control; Takagi-Sugeno fuzzy model; Upper bound; Valves
• ISSN: 1063-6706; 1941-0034
• DOI: 10.1109/TFUZZ.2024.3469272

Load frequency control (LFC) is crucial for ensuring the frequency stability of power system, and its control performance is often affected by nonlinearities in devices and multi-source-induced hybrid delays in control signal transmission networks. This paper investigates the LFC performance analysis and improvement of power systems under the nonlinearities and hybrid delays. Firstly, the nonlinear part is approximated by a T-S fuzzy model and the hybrid delay is divided into two regions, thus establishing a T-S fuzzy LFC model with hybrid delays. Then, based on switched system theory, a delay-dependent weighted <inline-formula><tex-math notation="LaTeX">H_\infty</tex-math></inline-formula> performance analysis criterion for LFC system is proposed, giving the necessary conditions to achieve a certain robustness of the system against disturbances. On this basis, a controller design method is proposed to ensure the system have the optimal level of disturbance rejection under the designed controller. Finally, case studies based on single-area and three-area LFC demonstrate that, compared with previous methods, the proposed method can obtain a larger allowable upper bound of delays and better <inline-formula><tex-math notation="LaTeX">H_\infty</tex-math></inline-formula> performance estimation. Based on this, the designed controller enhances the robust performance of LFC, thereby ensuring the stable operation of power systems under nonlinearities and hybrid delays.