Energies (Mar 2024)

FLC-Based Ultra-Low-Frequency Oscillation Suppression Scheme for Interconnected Power Grids

  • Chao Xing,
  • Mingqun Liu,
  • Junzhen Peng,
  • Yuhong Wang,
  • Yichen Zhou,
  • Zongsheng Zheng,
  • Shilin Gao,
  • Jianquan Liao

DOI
https://doi.org/10.3390/en17061300
Journal volume & issue
Vol. 17, no. 6
p. 1300

Abstract

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The appearance of ultra-low-frequency oscillations in the grid at the sending end, after asynchronous grid interconnection, poses a significant threat to the stable operation of the system. For post-asynchronous interconnection in a multi-DC transmission system, an investigation is conducted to analyze the causes of ultra-low-frequency oscillations and the utilization of a Frequency Limit Controller (FLC) which aims to suppress these oscillations. Furthermore, a method is developed to rank DC sensitivity, considering the hydroelectric distribution in the sending-end grid, by combining the DC FLC impact factor and DC control sensitivity. Subsequently, a novel approach for ultra-low-frequency oscillation suppression is proposed. This approach employs the stochastic subspace method for parameter estimation and the NSGA-II optimization algorithm to convert the multi-DC optimization challenge into multiple sequential cyclic optimization problems, each focusing on a single DC, ensuring a more effective suppression of ultra-low-frequency oscillations. The proposed scheme’s effectiveness is validated through simulations using a specific locations’ interconnected power grid.

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