柔性直流换流阀交流侧桥臂环流异常分析

Analysis of Abnormal Condition of Circulating Current of the Bridge in the HVDC Flexible Valve

柔性直流输电技术在孤岛供电、城市电网供电、分布式能源并网等方面具有很高的应用价值。介绍了上海柔性直流输电示范工程的概况、系统电气接线和运行方式,分析了柔性直流试运行过程中出现的一起故障案例。由于桥臂环流控制参数和结构不够优化,使得柔性直流换流阀的桥臂环流在长期运行中逐步增大,出现不可控而引发桥臂过流保护动作。通过调试,优化了环流控制程序的参数和结构,提升了系统控制性能,解决了换流阀交流侧桥臂电流异常问题。

HVDC Flexible has great application value in power transmission of solitary island,urban power grid and grid connection of distributed generation.In this paper,the general situation,system connection and operation mode of Shanghai HVDC flexible transmission demonstration project is introduced.Then a fault of the system is analysed.In the trial operation,because the control parameters and structure of the bridge was not adequate,the circulating current of the bridge in the HVDC flexible value increased progressively.And finally overcurrent protection action occurred.The parameters and structure of the bridge was optimized through commissioning,the control performance of the system was improved and the problem was solved as last.