电价下行下沅水梯级水电站群中长期联合调度策略研究

为研究电力市场规则下沅水流域梯级水电站中长期调度运行最优策略,以沅水干流三板溪、白市、托口、五强溪4座水电站为实例,构建了梯级水电站群发电效益最大模型,并提出轮库迭代增量动态规划方法进行求解。通过对不同水文年型不同现行电价下进行梯级水电站优化调度计算,得出中长期沅水流域梯级水电站联合优化调度策略。研究表明,三板溪水电站在梯级中起到重要调蓄作用,随着上网电价的同步下降,三板溪消落水位将上升,上网电价每下降0.02元/(kW·h),三板溪消落水位在丰水年、平水年、枯水年分别上涨1.09、0.20、1.34 m。该模型方法可有效提升沅水流域梯级电站群发电效益,为电站管理人员提供科学的调度策略,提升水资源利用效率。     

市场环境下梯级水电站短期优化调度研究

市场环境下,梯级水水电站的短期调度竞价报送发电计划阶段,根据预测的边际电价和入库流量,以发电收益最大化为目标制定短期调度计划;电网负荷下达阶段,根据电网下达日内96点负荷和预测的入库流量制定短期调度计划。后者在流域梯级统一调度背景下,若梯级水电站具有流域统一电价,梯级水电站短期调度以耗水量最小为目标进行优化;若梯级水电站具有不同电价,则梯级水电站短期调度以发电收入最大为目标进行优化。以市场环境下不同阶段梯级水电站制定短期优化调度计划为对象,研究梯级水电站短期优化调度模型及其求解算法,构建梯级水电站短期优化调度整体框架。研究表明,市场环境下不同阶段采用不同模型进行短期优化调度,可节约梯级水资源、增加梯级发电收益。     

沅水流域梯级水电站联合优化运行研究

为了实现梯级水电站联合优化运行,充分发挥梯级水库群的调节作用,针对沅水流域三板溪、白市、托口、洪江、碗米坡、五强溪等6座水电站,分别构建梯级水电站发电量最大模型和发电效益最大模型,采用逐步优化—逐次逼近动态规划混合算法进行求解。由两种模型计算得出:与单一水库优化调度相比,在丰、平、枯水年份,沅水梯级水电站发电量最大目标可分别增加发电量3. 666亿kW·h、4. 884亿kW·h和1. 549亿kW·h,发电效益最大目标可分别增加0. 993亿元、1. 22亿元和0. 377亿元。最后分析总结沅水梯级水电站联合运行两种目标下的最优运行策略,为梯级水电站的优化运行提供理论依据和技术支持。     

流域梯级水资源管理决策支持系统关键技术研究——以金沙江下游—三峡梯级水电站为例

水资源管理决策支持系统是水库群实现防洪、发电、生态等综合优化调度目标的重要支撑。以金沙江下游—三峡梯级水电站为研究对象,针对流域梯级水资源管理面临的突出问题,研发了水资源管理决策支持系统,总结了巨型水电能源系统多源异构数据收集与处理、长江上游水库群调度智能模拟、河道水文过程及水库下游泄水波演进模拟、流域梯级水电站群长中短期嵌套联合发电优化调度、预报调度效益定量评估指标及后评估体系、流域一体化水资源管理模式下多业务嵌套重构等6大关键技术,为金沙江下游—三峡梯级水电站的水资源优化管理提供科学依据。     

节能发电调度规则下梯级水电站调度方式研究

流域集控中心负责对梯级各水电站的统一调度管理,打破了原有单站式的调度运行模式.流域集控中心取得梯级发电调度权之后,为保证电网安全稳定运行和节能发电调度工作的顺利实施,提出了节能发电调度单站排序规则下的梯级水电站若干调度方案,指出:应考虑河川径流年内来水特性、水库综合运用方式、电力负荷需求、社会效益等因素,针对流域梯级水电站自身特点,结合电网安全约束、临时调度调整、机组启停损耗、防洪、生态用水等限制条件,选择集控中心模式下具有可操作性和指导性的流域梯级水电站节能发电调度实施方案.     

复杂水利-电力约束下梯级水电站短期多层级多目标优化调度研究

电网高强度的调峰调频任务和流域严格的水量调度要求,限制了梯级水电站调度运行的优化空间,造成水调电调协调困难、效益发挥不充分、机组长时间低效运行等问题。本文统筹考虑梯级水电站发电效益、调峰能力以及运行工况等目标,分别建立电网、梯级、电站等不同层级的调度模型,研究多层级多目标协同优化机制,提出模型求解方法。通过不同层级之间相互嵌套,滚动向前,在复杂水利-电力约束条件下保证梯级电站的安全高效运行。以黄河上游水电基地为例,该方法可在保障黄河流域水量调度要求和西北地区高比例风光全额消纳前提下,将梯级水电站发电量提升2.75%,耗水率降低2.38%,机组低效运行时间降低50.64%,且有效提升水电调峰能力,平滑了火电出力过程,对于梯级水电科学调度和安全运行具有科学意义和实际价值。     

柳江流域梯级水库调度系统的设计开发与应用

介绍了柳江流域梯级水库调度系统的设计原则和应用方法。水库调度管理是水电站管理的核心,目前单库优化调度比较成熟,但在同一条河流上各梯级电站实现上下游协同调度、最大程度地发挥整个流域的整体效益方面实践尚少。流域梯级水库调度系统利用现代信息化手段,通过集中采集上下游电站的发电量、发电水头等数据,协调调频、调峰的关系;采取库容补偿、水文补偿等方式,减少水库弃水和单位电能发电耗水量;统一整编、整体预报,开展联合优化调度,以获得比单库优化调度更优的经济效益,实现全流域发电、防洪、航运等多项综合效益提升,对梯级水电站运营的先进管理模式进行了有效探索,可为实现流域梯级电站调度综合最优化管理提供一定的借鉴。     

金沙江干流梯级水电站水库群长期优化调度

以金沙江干流梯级水电站水库群为研究对象,建立了金沙江梯级水电站水库群兼顾保证出力要求的以发电量最大为目标的长期优化调度模型;考虑水电系统的调峰要求,建立了金沙江梯级发电量最大长期优化调度模型.均用逐次逼近动态规划法求解,结果表明,调峰系数不同对梯级水电站发电效益及运行方式有明显影响.     

金沙江梯级水库消落运用方式研究

梯级水库消落运用方式是充分发挥梯级水库综合经济效益的重要课题,如何科学控制各电站枯期消落水位、兼顾梯级总发电效益并控制弃水是梯级水库枯水期联合调度的关键。本文在分析屏山水文站枯水期及汛前径流规律的基础上,探讨了金沙江梯级近期水平下溪洛渡和向家坝电站不同消落深度对总体运行调度的影响,提出5月、6月分旬控制消落的金沙江梯级水库枯期消落方案,并对不同频率来水情况下不同消落方式的发电效益进行了比较,然后,以金沙江下游乌东德、白鹤滩、溪洛渡和向家坝四库梯级电站群为研究对象,对金沙江四库联合运行时枯期消落方式进行初步研究,所得结论可供金沙江梯级水库在实际运行中制定调度方案参考。     

松江河梯级水电站短期优化调度数学模型分析

应用改进粒子群算法求解松江河梯级水电站短期优化调度问题,建立梯级电站发电量最大和发电效益最大短期优化调度数学模型。针对粒子群算法存在的后期收敛速度慢和易陷入局部最优等缺点,引入收缩因子和基于遗传思想的变异算子对其进行改进。应用改进粒子群算法对松江河梯级水电站进行短期优化调度,分别采用发电量最大和发电效益最大数学模型进行算例分析。结果表明：对梯级电站进行短期优化调度可以提高梯级电站的整体质量和效益;应用改进粒子群算法求解梯级电站短期优化调度问题在求解时间、精度上都取得了满意的效果。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.