基于动态实验的双馈抽水蓄能机组空载特性与变速演化

No-load Characteristics and Variable Speed Evolution of Doubly-fed Pumped Storage Unit Based on Dynamic Experiment Platform

可变速抽水蓄能具备调节速动性、高效性、灵活性、可靠性等优势,是全球抽水蓄能发展的新方向。然而,国内暂无已投运的双馈抽水蓄能电站,对变速机组动态特性和控制策略研究多依赖数值仿真,并且严重缺乏运行数据支持和真机验证。该文依托国内首台可变速抽水蓄能动态特性实验台,通过不同水头不同转速下模型实验分析变速机组的空载特性,揭示空载变速运行背后的演化规律。提出迁移里程和工况点斜率等量化指标,并纳入到可变速机组空载性能评估中,进一步提出适用于可变速机组的发电快速启动策略并集成于监控系统。运行结果表明,变速机组可以突破反“S”特性区和并网同期带的约束,节约常规启动时间47.87%,最大可降低空载无叶区压力脉动幅值45.54%,有望从根本上解决低水头条件由空载频率波动导致的并网难问题。

Doubly-fed variable speed pumped storage is the new development direction of pumped storage technology all over the world because of their advantages such as quick adjustment,high efficiency,flexibility and reliability.However,there is no operational doubly-fed pumped storage plant in China.The study of the dynamic characteristics and control strategy of variable speed units relies on numerical simulation without operation data support and measurement verification.The no-load characteristic of VSPSU was analyzed and the evolution mechanism of variable-speed operating point was revealed by model experiments of different heads and rotating speeds based on the VSPSU experiment platform.The migration distance and operating point slope were put forward to quantify no-load performance.The novel quick start strategy for VSPSU is further proposed and integrated into the monitoring system.The operation results show that the proposed strategy could break through the constraints of the“S”characteristic region and the grid-connected synchronous zone,save the normal starting time by 47.87%,and reduce the maximum amplitude of pressure pulsation by 45.54%.The difficulty of grid connection caused by the fluctuation of no-load frequency in low head conditions could be fundamentally solved.