TY  - EJOU
AU  - Zhuang, Guofeng 
AU  - Zhao, Xiuzhen 
AU  - Luo, Xuemei 
AU  - Chen, Shibin 
AU  - Zhang, Xujun 

TI  - Mechanism Analysis and Detection Methods of Voltage Fluctuation under Wide-Band Oscillation
T2  - Energy Engineering

PY  - 
VL  - 
IS  - 
SN  - 1546-0118

AB  - This paper investigates voltage fluctuations in direct-drive wind farms induced by wide-band oscillations during grid integration. A sequence impedance model of the wind farm is established, incorporating key components such as direct-drive wind turbines, static var generators (SVGs), transformers, and transmission lines. Based on this model, positive- and negative-sequence impedance expressions are derived. The quantitative relationship among voltage fluctuation, system strength (short-circuit ratio, SCR), and power imbalance is formulated, leading to a comprehensive expression that highlights the influence of impedance mismatch between positive and negative sequences on wide-band oscillations. Simulation results confirm an approximately linear correlation between voltage fluctuation and power imbalance, and validate the inverse relationship between voltage fluctuation and system strength. Sensitivity analysis and modal participation factor analysis are further conducted to identify the voltage response characteristics under active and reactive power disturbances, revealing that capacitor voltage, q-axis current, and phase-locked loop (PLL) states are the dominant factors driving voltage fluctuations in the wide-band frequency domain. To mitigate these effects, a frequency-weighted adaptive virtual impedance shaping (FW-AVZ) method is proposed for both positive and negative sequences. The method effectively equalizes sequence impedances, improves phase margin, and suppresses voltage fluctuations across a wide frequency range. The findings provide theoretical insights and practical guidance for enhancing voltage stability in direct-drive wind farms under weak grid conditions.
KW  - Direct-drive wind farm; wide-band oscillation; voltage fluctuation; sequential impedance modeling; power imbalance

DO  - 10.32604/ee.2026.072999