风电场通过柔性直流方式接入孤立电网的稳定研究

发布时间：2018-10-20 18:44

【摘要】：风电场大规模集中接入电网后,带来了诸多不利影响,不仅容易出现电压水平降低、电压波动以及频率波动的问题,还会带来系统暂态稳定性变差等严重问题,传统的交流输电方式并不能缓解风电大规模接入电网引起的负面影响。柔性直流输电方式基于具有自换向特性的电压源换流器,并采用脉宽调制技术,实现了有功无功的解耦,使得独立连续的调节成为可能。柔性直流输电技术凭借其多方面的优势,为风电大规模集中接入电网提拱了新的解决途径和技术方案,因此研究风电场通过柔性直流方式接入电网具有重要意义。本文针对柔性直流输电在风电接入电网中的应用进行了研究,首先总结了各国的风电并网导则,阐述了我国大规模风电集中接入的可能,接下来对较为成熟的双馈风力发电机组数学模型和柔性直流输电数学模型进行了坐标变换,将模型予以简化,之后提出了适用于风电场接入的柔性直流控制策略,最后利用PSS/E仿真工具对辽宁某地区孤立电网进行仿真实验,验证了柔性直流输电在动态补偿系统缺失无功、维持系统电压稳定以及抑制系统频率波动等方面的有利作用,为柔性直流输电技术应用在风电接入电网提供了有益的参考价值。
[Abstract]:After the wind farm is connected to the power network on a large scale, it brings a lot of adverse effects. It is not only easy to reduce the voltage level, voltage fluctuation and frequency fluctuation, but also bring serious problems such as the deterioration of the transient stability of the system. The traditional AC transmission method can not alleviate the negative impact caused by large-scale wind power grid access. The flexible DC transmission mode is based on the voltage source converter with the characteristic of self-commutation and adopts the pulse width modulation technology to realize the decoupling of active and reactive power which makes it possible to adjust independently and continuously. Flexible DC transmission technology, with its advantages in many aspects, provides a new solution and technical scheme for large-scale centralized wind power grid access, so it is of great significance to study wind farm access to power grid through flexible DC mode. In this paper, the application of flexible direct current transmission in wind power grid is studied. Firstly, the guide of wind power connection in various countries is summarized, and the possibility of large-scale wind power centralized access in China is discussed. Then coordinate transformation is carried out on the more mature mathematical model of doubly-fed wind turbine and flexible direct current transmission, and the model is simplified, and then a flexible DC control strategy suitable for wind farm access is proposed. Finally, the simulation experiment of isolated power grid in a certain area of Liaoning province is carried out by using PSS/E simulation tool, which verifies the advantages of flexible direct current transmission in dynamic compensation system for missing reactive power, maintaining system voltage stability and restraining system frequency fluctuation. It provides a useful reference for the application of flexible direct current transmission technology in wind power grid.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM614

【参考文献】