Volt/Var Control for Power Grids With Connections of Large-Scale Wind Farms: A Review

Large-scale wind farms (LSWFs) have become a popular form of exploiting abundant wind energy. However, the integration of LSWFs presents challenges to the volt/var control (VVC) of power grids. In this regard, various VVC methods for power grids with connections of LSWFs have been proposed from different viewpoints. This paper provides a comprehensive review on VVC for power grids with connections of LSWFs. First, the challenges presented by LSWFs to VVC are investigated with regard to the uncertainty of power flow and voltage, conflicts of VVCs among interconnected power grids, operation of discrete devices, voltage stability, and reactive power market. Second, an overview on current research regarding VVC methods for LSWFs connected power grids is presented, where the VVC methods are classified into three categories: decentralized VVC, centralized VVC, and hierarchical VVC. The three categories of VVC methods are analyzed and compared in terms of their advantages, disadvantages, and applications. In addition, drawbacks of current research are concluded. Finally, to overcome the drawbacks presented in current research, this paper provides directions for future research, including event-triggered VVC methods, big data techniques, reactive power markets, energy storage systems, and VSC-based HVDC.