水头衔接的梯级电站水头分配问题研究

Water-head allocation in cascade hydropower stations with water-head connection

对于水头衔接的梯级电站,在两梯级电站总水头不变情况下抬高下游电站运行水位,一方面会增加弃水风险,另一方面会改变两电站利用水头,从而使两电站发电收益发生变化。为了研究抬高下游电站运行水位对梯级电站整体发电收益的影响,计算了抬高下游电站运行水位前后梯级电站收益变化,提出了发电用水增量系数评价指标,并基于弃水损失,研究了改变梯级电站水头分配后电站发电收益变化,给出了改变梯级电站水头分配是否有利于提高梯级电站总收益的判别条件,并以清江隔河岩、高坝洲梯级电站为例进行了探讨。结果表明:鉴于上下游电站电价、综合出力系数的差异,当满足提出的判别条件时,适当抬高下游电站运行水位可增加梯级电站的整体发电收益。研究成果可为梯级电站科学控制水位、平衡弃水风险和水头效益、提高整体发电收益提供理论参考。

For cascade hydropower stations with water-head connection,raising the water level of the downstream hydropower station in the case of unchanged total water head of two stations may increase the risk of water abandonment,and change the utilized head of the two cascade hydropower stations which results in changing their revenue.To research the effect of raising water level of downstream hydropower station on cascade generation revenue,the revenue of cascade stations before and after raising the water level of the downstream station was calculated.The coefficient of water consumption increment(CWI)was proposed.Then considering the loss of water abandonment,the effect of changing head allocation on generation revenue of cascade stations was researched.This study presented a criterion that whether changing water-head allocation is beneficial to increasing revenue of cascade stations.A case study of the Qingjiang River cascade hydropower stations indicated that due to the differences in electricity prices and comprehensive efficiency coefficients between upstream and downstream hydropower stations,when the criterion is satisfied,appropriately increasing the water level of the downstream hydropower station may increase the overall power generation revenue of cascades.The research results can provide theoretic guidance for cascade hydropower stations to scientifically control water level,balance risk of water abandonment and water-head benefit,and increase overall power generation revenue.