水电能源科学

非恒定摩阻在管道系统的水锤现象中具有非常复杂的作用，对于超长引水隧洞电站，充分考虑非恒定摩阻的影响十分必要。对此，开展考虑基于非恒定摩阻的超长引水隧洞水电站非线性暂态响应特性研究。首先，利用特征线法建立了基于瞬时加速度的非恒定摩阻的超长引水隧洞水电站系统模型，然后进行该模型在负荷及频率扰动下的仿真计算，最后使用伯德图法对该模型在频率扰动下的稳定性进行评估，并结合能量方程研究非恒定摩阻参数对系统稳定性的影响。结果表明，管道的非恒定摩阻主要作用于超长引水隧洞电站水轮机快速响应阶段。局部加速度影响系数(k_t)、对流加速度影响系数(k_l)增大时，系统稳定性变差。此外，k_t、k_l的变化对系统在受到高频扰动时表现得更加敏感。

Unsteady friction plays a very complex role in the water hammer phenomenon within pipeline systems. For hydropower station with super-long headrace tunnel(SLHT), it is crucial to consider the effects of unsteady friction adequately. This paper conducts a study on the nonlinear transient response characteristics of hydropower station with SLHT based on unsteady friction. Firstly, a system model of hydropower station with SLHT is established using the method of characteristics, incorporating unsteady friction based on instantaneous acceleration. Then, simulations of this model are performed under load and frequency disturbances. Finally, the stability of the model under frequency disturbances is evaluated using the Bode plot method, and the impact of unsteady friction parameters on system stability is investigated in conjunction with the energy equation. The results show that the unsteady friction in the pipeline primarily affects the rapid response phase of the water turbine in the hydropower station with SLHT. When the impact coefficients of local acceleration(k_t) and convective acceleration(k_l) increase, the system stability deteriorates. Moreover, changes in k_t and k_l make the system more sensitive to high-frequency disturbances.