Coordinated operation control on low DC voltage of HVDC integrating wind farms

• Main Authors: Qingzhi Zhang, Chenggong Zhao, Chuan Du
• Format: Article
• Language: English
• Published: Wiley 2019-01-01
• Series: The Journal of Engineering
• Subjects: wind power plants; power grids; HVDC power convertors; HVDC power transmission; wind turbines; coordinated operation control; low DC voltage; HVDC integrating wind farms; HVDC transmission technology; MMC-HVDC; conventional control methods; wind power integration system; direct-drive wind farm; independent control; wind turbine cut-off; DC voltage drops; constant AC voltage; wind power integration point; control strategy
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8567

In recent years, with the development of high voltage direct current (HVDC) transmission technology, wind power integration with modular multiple converter-HVDC (MMC-HVDC) has been widely researched and applied. However, the conventional control methods on wind power integration cannot match the flexibility needing of loads. In this paper, a wind power integration system with permanent magnet direct-drive wind farm and full-bridge MMC is proposed. It has the characteristics of independent control of AC and DC current, which can realise the stable operation of the system under low DC voltage, so that to effectively avoid the accident of the wind turbine cut-off caused by the load reduce. When the DC voltage drops, the system can maintain a constant AC voltage at the wind power integration point, so that the wind farm can operate normally. Finally, the simulation results in PSCAD/EMTDC show that the proposed system and its control strategy are correct.