设置尾水连通管的抽水蓄能电站引水发电系统小波动稳定分析

设置尾水连通管后,可缓解抽水蓄能电站相继甩负荷工况尾水管最小压力,但其对系统小扰动稳定性的影响还不清楚。本文建立了设有尾水连通管的抽水蓄能电站引水发电系统小波动状态方程,利用状态空间法对小扰动下机组转速、调压室水位等状态变量波动过程进行了稳定性分析,并与基于特征线法的弹性模型计算结果进行了对比,验证本文理论分析模型的正确性。同时基于理论模型,研究了尾水连通管对于系统小波动稳定性产生的影响,并对连通管管径及位置进行了敏感性分析,得出以下结论:尾水连通管及其管径的大小、设置位置对于系统小波动稳定域、机组转速变化及调压室水位波动过程产生的影响基本可以忽略;设置尾水连通管后,系统小波动过渡过程中,尾水支管流量发生变化,使得两侧尾水支管压力平衡,但并不增加整体系统的阻抗。

Stability analysis of hydroelectric generating system of the pumped storage power plant with connection pipe between tailrace tunnels

The connection pipe between the tailrace tunnels can effectively improve the minimum pressure at the draft tube during successive load rejection, however its impacts on the system stability under small load disturbance are unclear. The stability of the parameters,such as the rotating speed,water level fluctuations in the surge tank are analyzed by using state space methods. The results of the state space model are compared with the results of elastic model that is based on the method of characteristics to verify the correct of analytical model. Meanwhile,the effect of connection pipe on the system stability are investigated based on the analytical model, and the sensitive analysis of the connection pipe diameters and locations are studied. The conclusions are as follow. The effect of connection pipe as well as its diameters and locations on the system stable area,the dynamic process of rotating speed of runner and water level fluctuation in surge tank can be almost neglected. With the connection pipe between tailrace tunnels, the discharge in the tailrace tunnel will be changed to balance the pressure between tailrace tunnels during the small load disturbance conditions,while the system resistance is not increased.