中文摘要：

超长引水隧洞水电站水流惯性巨大，导致调压室水位波动周期长、振幅大、衰减慢，孤网条件下，采用PI或PID调节，超长引水隧洞水电站的小波动调节品质较差，衰减较慢，常常需要增大调压室稳定断面面积来改善调节品质，工程代价较大。实际并网运行条件下水电站的小波动过渡过程的稳定性及调节品质，尚未见过这方面的研究报导，本文通过Matlab软件中的Simulink及Sim Power Systems工具箱构建超长引水隧洞水电站单机无穷大网的详细电力系统仿真模型，研究无穷大网条件下带超长引水隧洞水电站小波动稳定性及调节品质，为该类水电站的设计和运行控制提供参考和依据。

英文摘要：

For a hydropower station with long-distance diversion tunnel, extremely large inertia of the tunnel flow leads to long fluctuation cycles, large amplitudes and slow decay of the water level in its surge tank. For those stations on an isolated grid, the regulation quality of transient process in small fluctuations using the traditional PID control law is poor and the fluctuations decay slowly. In this case, the cross-sectional area of surge tank often needs to be increased to improve stability, resulting in a higher project cost. If the stations connect to an infinite power grid, however, no previous studies on their stability and regulation quality are available. This paper constructs a detailed simulation model of hydraulic-mechanical-electric systems on infinite power grid, using the platform of Matlab software and its toolbox of Simulink and SimPowerSystems. This model is used to study the stability and regulation quality of hydropower stations with long diversion under small fluctuations. The results lay a basis for design and operation control of such hydropower stations.