Disturbance rejection-based LFC for multi-area parallel interconnected AC/DC system

• Published in: IET generation, transmission & distribution Vol. 10; no. 16; pp. 4105 - 4117
• Main Authors: Chen, Chunyu, Zhang, Kaifeng, Yuan, Kun, Gao, Zonghe, Teng, Xianliang, Ding, Qia
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 08.12.2016
• Subjects: AC tie‐lie interchange power stability; AC‐DC hybrid system; composite feedback controller design; control system synthesis; disturbance rejection‐based LFC; DRB LFC schemes; electrical safety; feedback; frequency control; large‐capacity power transmission; load frequency control; load regulation; long‐distance power transmission; multiarea parallel interconnected AC‐DC system; power grid operational safety; power grids; power imbalance elimination; power system interconnection; power system stability; power transmission control; large-capacity power transmission; power system stability; electrical safety; AC tie-lie interchange power stability; control system synthesis; frequency control; multiarea parallel interconnected AC-DC system; composite feedback controller design; long-distance power transmission; power transmission control; feedback; AC-DC hybrid system; load frequency control; power imbalance elimination; disturbance rejection-based LFC; power system interconnection; DRB LFC schemes; power grids; power grid operational safety; load regulation
• DOI: 10.1049/iet-gtd.2016.0526
• ISSN: 1751-8687; 1751-8695

AC/DC hybrid system plays an important role in large-capacity and long-distance power transmission. Moreover, load frequency control (LFC) of AC/DC hybrid system is very essential for the safe operation of power grid. Since LFC in essence stems from the power imbalance of the area caused by the variations of the generating and consuming party, this study presents a novel disturbance rejection-based (DRB) LFC scheme to eliminate this power imbalance, thus achieving frequency and AC tie-lie interchange power stability. This study assumes only part of the LFC system states information is measurable and utilises extended states observer to estimate the unmeasurable states including the disturbances. Moreover, then a composite feedback controller is designed utilising both the measurable and observed states information. The proposed DRB LFC schemes retain the structure of the LFC model and sufficiently utilise measurable states information for controller design, which has good engineering applicability compared with robust or intelligent LFC scheme. A multi-area system containing three subareas with parallel interconnected AC/DC link is studied and the simulation results show the effectiveness of the proposed methods.