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Transient Instability of Synchronous Condenser Co-located with Voltage Source Converters under Non-Metallic Faults
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  • xinyu liu ,
  • Huanhai Xin ,
  • Yongpeng Shang ,
  • Di Zheng
xinyu liu
Zhejiang University

Corresponding Author:[email protected]

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Huanhai Xin
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Yongpeng Shang
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Abstract

Synchronous Condensers (SynCons) are widely used in the voltage source converter (VSC) integrated weak grid for voltage support and oscillation suppression. Whereas recent research suggests that the SynCon may accelerate and lose transient rotor angle stability due to the excessive active power injected by nearby VSCs during metallic faults. However, the transient stability of the SynCon cannot be guaranteed even if it decelerates during non-metallic faults. To reveal this phenomenon, the transient stability of SynCon during non-metallic faults is investigated in this paper. After deriving power-angle characteristics in different operating conditions, a novel transient instability mechanism is discovered, and the effect of the system parameters is analyzed based on the Equal Area Criterion (EAC). It reveals that inertia, excitation, VSC size, and voltage support during FRT all contribute to such transient instability. To mitigate unbalanced active power during faults and improve transient stability, an adaptive fault ride-through (FRT) strategy is proposed. The electromagnetic transient (EMT) simulations based on the PSCAD/EMTDC are carried out to validate the effectiveness of the theoretical analysis and the proposed adaptive control strategy.