含引水和尾水明渠输水的水电站过渡过程分析

鉴于无压明渠的水力特性直接影响含明渠引水式水电站的过渡过程和运行控制,结合有压输水系统的特征线法,采用明渠瞬变流分析的特征隐式格式和相应的边界条件,构建含非自动调节引水明渠、压力前池、尾水池和尾水明渠的引水式水电站的过渡过程分析模型,研究了明渠流水力特性对水电站过渡过程和稳定性的影响。结果表明,在大波动过渡过程中,明渠流水力特性对机组蜗壳进口内水压力和转速极值的影响很小,而尾水渠水力特性及尾水池最低涌波水位决定了尾水管进口的最小内水压力;考虑明渠瞬变流特性的影响,水力干扰下受扰机组的调节品质变化较为明显,而水力-机械系统小波动调节品质变化较小。

Hydraulic Transient Process Analysis of Water diversion Hydropower Station with Water Diversion Channel and Tail Channel

The hydraulic characteristics of channel flow have direct effect on the hydraulic transient and operation control of water diversion hydropower stations with open channel. Combined with the method of characteristic in pressurized water conveyance systems, the characteristic implicit format for hydraulic transient analysis of open channel and the corresponding boundary conditions were derived. And then the mathematical model of hydraulic transient analysis was built for the water diversion hydropower station with a non automatic regulation channel, head pond, tail pond and tail channel. The impact of hydraulic characteristics of channel flow on hydraulic transient and operation stability of hydropower station was investigated. The results indicate that the hydraulic characteristics of channel flow has less impact on the extreme water pressure at inlet of spiral case and maximum unit speed, and the minimum surge in tail pond will lead to minimum water pressure at inlet of draft tube; Considering the effect of channel flow''s transient characteristics, the regulation performance of disturbed units under hydraulic disturbance has obvious change while stability of small fluctuation has less difference.