Wind Power Fluctuation Smoothing Controller Based on Risk Assessment of Grid Frequency Deviation in an Isolated System

Jin Lin, Yuanzhang Sun, Yonghua Song, Wenzhong Gao, Poul Ejnar Sørensen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Wind power fluctuation raises the security concern of grid frequency deviation, especially for an isolated power system. Thus, better control methodology needs to be developed to smooth the fluctuation without excessive spillage. Based on an actual industrial power system, this paper proposes a smoothing controller to suppress the power fluctuation from doubly-fed induction generator (DFIG)-based wind farm. This controller consists of threemain functionality components: risk assessmentmodel, wind turbine rotor speed optimizer, and rotor speed upper limiter. In order to avoid unnecessary energy loss, this paper designs a risk assessment model of grid frequency deviation, which is capable of locally estimating the maximum grid frequency deviation risk of the next dispatch cycle. A wind turbine speed optimizer then uses the estimated frequency deviation risk to search for the optimal power curve with reduced output so that a trade-off between fluctuation smoothing and energy loss is achieved. Subsequently, the controller limits the maximum rotor speed to shift down the power curve of wind power plant based on the optimal wind turbine rotor speed. Therefore, the power fluctuation is smoothed along with the down-regulated power curve. A numerical case study demonstrates the effectiveness and economy of this smoothing controller for the studied isolated system.
Original languageEnglish
JournalI E E E Transactions on Sustainable Energy
Volume4
Issue number2
Pages (from-to)379-392
ISSN1949-3029
DOIs
Publication statusPublished - 2013

Keywords

  • Binary search algorithm
  • Doubly-fed induction generator (DFIG)
  • Energy loss
  • Frequency deviation
  • Maximum speed limiter
  • “Time-Frequency” assessment model
  • Power fluctuation

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