Imbalance recovery performance analysis and improvement for MMC‐HVDC systems considering DC current dynamics. Issue 13 (30th April 2020)

• Record Type: Journal Article
• Authors: Liu, Ziwen; Zhao, Jinquan; Zhu, Yaoliang
• Is Part Of: IET generation, transmission & distribution. Volume 14:Issue 13(2020)
• Page Start: 2488
• Page End: 2497
• Publication Date: 2020-04-30
• Subjects: power system control -- control system synthesis -- compensation -- HVDC power convertors -- stability -- feedback -- electric current control -- voltage control -- HVDC power transmission; imbalance recovery performance analysis -- MMC‐HVDC systems -- dc current dynamics -- modular multilevel converter high voltage direct current systems -- enhanced control -- imbalance recovery speed -- MMC phase unit -- poor imbalance recovery performance -- auxiliary control -- improved control -- adaptive virtual resistance method -- recovery time -- system operating states -- control parameter design -- dc current components rebalance controller -- system internal response -- improved stability recovery performance; Electric power production -- Periodicals; Electric power transmission -- Periodicals; Electric power distribution -- Periodicals; 621.3105
• DOI: 10.1049/iet-gtd.2019.1481
• Languages: English
• ISSNs: 1751-8687

Abstract

Abstract : This study presents the imbalance recovery performance analysis of modular multilevel converter high voltage direct current (MMC‐HVDC) systems considering dc current dynamics, and proposes an enhanced control to improve the system's internal stability response. The numerical expressions of the imbalance recovery speed and overshoot amplitude response of dc current components in upper and lower arms of the MMC phase unit are firstly derived analytically, which reveal that the system can be prone to poor imbalance recovery performance after sudden disturbance impacts with no auxiliary control. According to the analysis results, an improved control based on the adaptive virtual resistance method is proposed for the MMC‐HVDC systems to reduce the recovery time regarding different system operating states. The key control parameter design of the adaptive virtual resistance is also simplified since a wider adjustment range of the parameters is allowed in the proposed method. In addition, the dc current components rebalance controller consisting of a low‐pass compensator is proposed to further reduce the overshoot amplitude of system internal response. With the implementation of the proposed control schemes, improved stability recovery performance of MMC‐HVDC systems can be achieved. Simulation results verify the effectiveness of the proposed control.