可变速抽蓄机组运行转速对甩负荷过渡过程的影响

为了分析可变速抽水蓄能机组初始运行转速对甩负荷过渡过程调节保证参数的影响，针对可变速抽水蓄能机组的运行特点，基于一维瞬变流理论特征线法，建立了可变速抽水蓄能电站初始运行转速计算及过渡过程仿真模型，结合工程算例，分析了不同水头运行条件下机组运行转速对发电效率的影响，研究了可变速抽水蓄能机组起始运行转速变化对事故甩负荷工况水锤升压和转速上升率的影响，并解释了其原因.结果表明：可变速抽水蓄能机组在高水头和额定水头下额定出力运行时，随着初始运行转速的减小，事故甩负荷后转速最大上升率增大，水锤升压增大.其原因在于可变速抽水蓄能机组初始转速的改变造成甩负荷过程中力矩和流量变化率发生变化.研究成果可为类似工程的运行转速选取和甩负荷过渡过程调保参数优化提供参考.

Influence of variable speed pumped-storage unit operating speed on load rejection transient process

In order to analyze the influence of the initial running speed of the variable speed pumped-storage unit on the load rejection transient process by adjusting the parameters of the guarantee, aiming at the operation characteristics of variable speed pumped storage unit, based on the theory of one-dimensional transient flow characteristic line method, the initial variable speed pumped-storage power station running speed calculation and transient process simulation model was established, combined with the engineering example, the influence of unit running speed on power generation efficiency under different head operating conditions, and the influence of variable speed pumped storage unit starting running speed on water hammer pressure and speed rising rate under the accident load rejection condition were studied, and the reasons for those were explained. The results show that when the variable speed pumped-storage unit is running at rated output under high water head and rated water head, with the decrease of initial operating speed, the maximum speed rising rate increases after the accident load rejection, and the water hammer pressure increases. The reason is that the change of initial speed of variable speed pumped-storage unit results in the change of torque and flow rate during the load rejection. The research results can provide reference for the selection of running speed and optimization of maintenance parameters in the transition process of load rejection in similar projects.