Main grid frequency support strategy for VSC-HVDC connected wind farms with variable speed wind turbines
Main grid frequency support strategy for VSC-HVDC connected wind farms with variable speed wind turbines
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变速风力发电机VSC-HVDC连接风电场的主电网频率支持策略
DOI：
10.1109/ptc.2011.6019348
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
T. Undeland
中科院分区：
文献类型：
--
作者：
T. M. Haileselassie;R. Torres;T. Vrana;K. Uhlen;T. Undeland
基于电压源换流器的高压直流输电（VSC-HVDC）连接的风电场（WF）导致海上交流电网完全“无惯性”。AC频率由WF侧的VSC-HVDC的控制确定，与主电网频率无关。此外，变速风力涡轮机的旋转速度与海上AC电网的AC频率无关。上述两个特征导致“无惯性”系统，即没有机械能存储来适应发电和负载的突然变化。“无惯性”系统不具有类似于具有惯性的传统AC电网的负载-频率响应，因此使得风力涡轮机难以对主电网的频率支持做出贡献。本文提出了一种风电场电网频率与主电网频率的人工耦合方法，使主电网频率得到风电场的支持。人工频率耦合通过使用用于DC电压控制的下垂控制器来实现。一个研究的案例，使用PSCAD，证明了人工频率耦合的有效性，主电网的频率支持。
A wind farm (WF) connected by voltage source converter-based HVDC (VSC-HVDC) results in a completely ‘inertia-less’ in offshore AC grid . AC frequency is determined by control of the VSC-HVDC on the WF side, independently of the main grid frequency. Moreover, the rotational speed of a variable speed wind turbine is independent of the AC frequency of the offshore AC grid. These two aforementioned features result in ‘inertia-less’ system, that is absence of mechanical energy storage to accomodate for abrupt changes in generation and load. An ‘inertia-less’ system does not have a load-frequency response similar to traditional AC grid with inertia, hence making it difficult for the wind turbines to contribute to frequency support of the main grid. This paper develops an artificial coupling of the wind farm grid and the main grid frequencies, for main grid frequency support by the wind farm. Artificial frequency coupling is achieved by use of droop controllers for the DC voltage control. A case of study, using PSCAD, demonstrates the effectiveness of artificial frequency coupling for the main grid frequency support.