清江梯级发电与生态均衡优化调度研究

Optimizing Operation of the Qingjiang Cascaded Hydropower Stations:Balancing Power Generation and Ecological Regulation

鉴于清江梯级水电站联合调度运行尚未考虑河流生态需求的现状,导致自然径流过程发生极大改变,采用逐旬频率计算法,确定清江梯级生态流量区间范围,进而在梯级发电调度的基础上,引入径流生态离差系数,建立发电与生态均衡优化调度模型,并提出了基于粒子群算法的模型解算方法,构建调度方案的发电与生态综合评价指标体系,对比分析清江梯级2008-2010年优化调度方案。结果表明,发电与生态均衡优化调度方案在梯级发电量仅减少1.85%的情况下,径流生态离差系数提高6.81%,梯级生态溢水量减少57.66亿m^3,梯级生态缺水量减少3.92亿m^3,生态调度效果显著。研究成果可为当前长江大保护与清江流域环境保护背景下清江梯级联合调度运行提供科学依据与决策支持。

Qingjiang River is the second largest tributary of the Yangtze River downstream of Three Gorges and three cascaded hydropower stations,Shuibuya,Geheyan and Gaobazhou,are operating on the river.Ecological operation of cascaded hydropower stations has become an important part of Yangtze River protection and river basin conservation.Additionally,water conservancy departments from provinces and cities have issued ecological flow requirements for numerous reaches of the river.To address these developments,we studied operating conditions that optimize the balance between power generation and ecological regulation for the three cascaded hydropower stations using ten day test periods.Firstly,a ten-day frequency method was used to calculate the ecological flow range for Qingjiang River.Then,an equilibrium operation model was developed for the cascaded dams to optimize the balance between power generation and ecological flow.The model uses an runoff deviation coefficient and is based on a particle swarm optimization method.A comprehensive index system of operation schemes was used to evaluate the model.Finally,we compared an operation scheme that considered only power generation with the equilibrium operation scheme using historical ten-day runoff data(2008-2010).Compared with the power generation operating scheme,the equilibrium operation increased the runoff dispersion coefficient by 6.81%,reduced cascade overflow by 5.766billion m^3 and reduced cascade water shortage by 392million m^3.Cascade power generation decreased only slightly,by 1.85%.The optimized operation scheme was examined greater detail by looking at the cascade operation during each 10-day period,of 2010.Discharge from the Shuibuya hydro-power station under the optimized operation scheme was close to the upper flow limit from period 1to 11,and ecological overflows decreased.The discharge was in the appropriate flow range from period 12to 15,and ecological water shortages decreased.From period 16to 36,ecological overflows occurred only in period 23.Under the power generation only scheme,an ecological water shortage occurred in periods 11to 14 at the Geheyan hydropower station and overflows occurred in periods 15,25and 29.Under the optimized operation scheme,Gaobazhou hydropower station maintained a high water level,with less fluctuation and a more stable power output.But with the power generation scheme,ecological overflow occurred in periods 8,15and 25,and a water shortage occurred from period 12to 14.In conclusion,the proposed optimal equilibrium scheme improved the ecological flow environment of the river under the pressure of water conservancy projects and provides a scientific basis and decision support for operating cascaded hydropower projects more ecologically.