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Common-Mode Frequency of Power Systems Affected by Voltage Dynamics
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  • Huisheng Gao ,
  • Huanhai Xin ,
  • Guang Hu ,
  • Bin Cao ,
  • Hui Yuan ,
  • Linbin Huang
Huisheng Gao
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Huanhai Xin
Zhejiang university, Zhejiang university

Corresponding Author:[email protected]

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Linbin Huang
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Abstract

The high penetration of converter-interfaced generation (CIGs) in power systems has raised concerns regarding the risk of frequency collapse. However, most existing theoretical analysis methods for system frequency assume constant bus voltages, which can lead to inaccurate results and potentially incorrect conclusions. The main challenge lies in the absence of analytical models that consider voltage dynamics when representing the system-level frequency. To address this issue, this article defines the voltage-influenced common-mode frequency (VCMF), which captures the dynamics of the system frequency in the scenario of non-constant bus voltages. The derivation process is implicitly based on the strong relationship between the consistent part of the bus frequencies (i.e., system frequency) and the rotational invariance of power flow. The expression of VCMF demonstrates that non-constant voltages affect the system frequency through a global term that involves the dynamics of all the devices, making its analysis challenging. Therefore, a network partitioning method based on the algebraic graph theory is proposed, which effectively divides the globally coupling term into several locally coupling terms, enabling a more tractable analysis of VCMF. Finally, simulations are used to validate the proposed method and confirm its validity.