含直驱风机风电场的电力系统次同步振荡机理与控制措施研究

The integration of wind farms consisting of direct drive wind turbine generators may lead to a newly found sub-synchronous oscillation (SSO) in power systems. Nowadays, the well accepted theories and analysis methods for traditional SSOs cannot properly interpret it. Considering the fact that more and more wind has to be abandoned due to the newly found SSO, there is an increasing concern about the new phenomenon, and a pressing need for new analysis methods and technical solutions to tackle this problem..In order to address the above concern, this project will focus on the following four aspects: searching for the theoretical mechanism of the new SSO based on the state space approach, adopting probabilistic method to assess the probability of the occurrence of SSO subject to uncertain operation conditions, developing a method to identify and locate oscillation sources/key factors based on the energy structure decomposition theory, and finding an on-line determination method to attenuate the SSO based on real time measurement. .The innovative parts of this project are probabilistic assessment of SSO and energy structure decomposition of the direct drive wind turbine generators. The achievement of this work will help to increase the utilization hour of wind generation, decrease the loss of wind curtailment，and thus provide theoretical foundations and technical solutions for the large scale integration of direct-drive-wind-turbine-generator based wind farms.

现有的电力系统次同步振荡理论无法解释含直驱风机风电场的电力系统中出现的次同步振荡现象，因次同步振荡导致大量弃风。本项目针对含直驱风机风电场的电力系统次同步振荡问题，将从直驱风机的详细电磁暂态模型出发，利用状态空间分析方法寻找振荡机理；考虑到风电场运行状态的不确定性，将根据系统中不确定电气量和设备参数的概率分布采用概率分析方法评估机理的正确性；利用能量结构分解的思想提出振荡源定位和关键因素在线辨识方法，并在此基础上提出基于在线量测的次同步振荡抑制措施。 .本项目的创新之处在于将风电场运行状态的不确定性纳入振荡机理分析中，保证所获机理的可信性；将基于在线量测的振荡源定位技术引入次同步振荡控制措施在线制定中，可避免对系统模型及参数的依赖。该项目的研究成果可填补含直驱风机风电场电力系统次同步振荡机理研究方面的空白，为抑制相关振荡现象提供理论基础和技术支撑。

2015年7月1日在我国新疆哈密地区发生的次同步振荡事故是全世界首例由直驱风机风电场引起的次同步振荡事故。这一事故呈现出一些新特点，难以用传统的次同步振荡机理和分析方法进行解释。本项目针对以“7·1”事故为代表的新型含直驱风机风电场的电力系统次同步振荡开展研究，为考虑风电随机性的次同步振荡分析提供了一系列方法。本项目针对含直驱风机风电场的电力系统次同步振荡现象，提出了对风电场等值模型在次同步振荡研究中适用性的评价方法，提出了快速生成具有次同步振荡风险系统场景的方法，解释了“7·1”事故中的次同步电流频率波动现象，提出了一种基于波形相关分析的谐波源检测方法，该方法可用于含直驱风场电力系统的振荡源定位，形成相应的控制措施抑制次同步振荡对系统的影响，从而填补含直驱风机风电场的电力系统次同步振荡机理研究方面的空白，为实际系统减少弃风损失提供理论基础和关键技术支撑。