直驱风电厂经MMC-HVDC外送系统稳定性分析及振荡抑制策略

Stability analysis and oscillation suppression strategy for direct-drive wind farms via MMC-HVDC transmission systems

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DOI 10.12208/j.jeea.20250203
刊名
Journal of Electrical Engineering and Automation
年,卷(期) 2025, 4(6)
作者
作者单位

南京邮电大学自动化学院 江苏南京

摘要
柔性高压直流输电技术(VSC-HVDC)已广泛应用于海上风电并网及远距离新能源输送,为新能源大规模接入电网提供了关键支撑。但风电场接入基于模块化多电平换流器的高压直流(MMC-HVDC)输电系统后,系统多控制环节间的耦合易引发小信号不稳定问题,威胁电网安全运行。尤其是在低频段,锁相环的动态特性与电流/电压控制环的交互作用,可能导致近工频振荡。为此,本文基于阻抗稳定性分析理论,研究风电柔直系统的建模与振荡抑制问题。首先,采用多谐波线性化方法,分别建立风电场与MMC的交流侧小信号阻抗模型,并通过扫频验证了理论阻抗的准确性。然后,基于阻抗稳定性分析理论,揭示系统各控制环节参数对稳定性的影响,并提出一种基于风电场侧锁相环的附加阻尼控制策略,通过引入二阶高通滤波器增强系统阻尼,有效抑制近工频振荡。最后搭建时域仿真模型,验证了所提方法对近工频振荡抑制的有效性。
Abstract
Voltage Source Converter-based High Voltage Direct Current (VSC-HVDC) technology has been widely applied in offshore wind power grid integration and long-distance renewable energy transmission, providing critical support for large-scale renewable energy integration into the power grid. However, when wind farms are connected through Modular Multilevel Converter-based HVDC (MMC-HVDC) systems, the coupling among multiple control loops may induce small-signal instability issues, posing a threat to the secure operation of the power system. In particular, at low-frequency ranges, the dynamic interaction between the phase-locked loop (PLL) and the current/voltage control loops can lead to near fundamental frequency oscillations. This paper investigates the modeling and oscillation suppression of wind power flexible DC transmission systems based on impedance stability analysis theory. Firstly, a multi-harmonic linearization method is employed to establish the AC-side small-signal impedance models of both the wind farm and the MMC, with the theoretical impedance validated by frequency sweep tests. Subsequently, based on impedance stability analysis, the impact of control loop parameters on system stability is revealed. A supplementary damping control strategy centered on the wind farm-side PLL is proposed, which enhances system damping by introducing a second-order high-pass filter, effectively suppressing near fundamental frequency oscillations. Finally, a time-domain simulation model is developed to verify the effectiveness of the proposed approach in mitigating near fundamental frequency oscillations.
关键词
风电并网;MMC-HVDC;多谐波线性化;阻抗模型;稳定性分析;锁相环;近工频振荡抑制
KeyWord
Wind power grid integration; MMC-HVDC; Multi-harmonic linearization; Impedance modeling; Stability analysis; Phase-locked loop (PLL); Near fundamental frequency oscillation suppression
基金项目
页码 25-36
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葛辉, 刘程子, 沈周钰, 杨艳, 尹永胜. 直驱风电厂经MMC-HVDC外送系统稳定性分析及振荡抑制策略 [J]. 电气工程与自动化. 2025; 4; (6). 25 - 36.

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