桓仁水库后汛二期洪水预报调度方式及调度规则制定

针对桓仁水库后汛二期弃水较多,洪水资源利用率不足,电厂效益低的问题,在分析桓仁水库后汛二期未来24h降水预报信息可利用性的基础上,制定了耦合洪水预报信息和降水预报信息的桓仁水库后汛二期实时防洪预报调度规则。风险分析结果表明,未来24h降水预报信息漏报时不会增加防洪风险,空报时也不会增加蓄水风险。应用所制定的洪水调度规则对13场实际洪水进行预报调度,在不降低原设计防洪标准的前提下,平均每场洪水减少弃水1.07×108 m3,增发电量1.96×106kW·h。研究成果可为水库后汛期洪水调度及资源化利用提供参考。     

云峰水库防洪预报调度研究

针对云峰水库无防洪库容与下游防洪需求之间的矛盾,以防御常规洪水及100年一遇以下设计洪水为目标,基于现有的洪水预报方案,采用分步试算的调洪计算方法,将预报累积净雨、库水位及入库流量作为改变水库出流的判别指标,研究制定了云峰水库预报调度方案。结果表明,采用预报调度方案指导水库防洪调度能有效提高下游防洪能力,水库可在短时间内完成预泄,并有充足的退水余量确保水库回蓄,对水库兴利影响甚小,调度方案合理可行。分步试算的调洪计算方法能适应复杂的调度规则,有效解决了水位出流关系在控制水位处存在跳跃间断点的问题。     

基于CFS预报产品的水电站水库预泄决策方法

针对降雨预报不确定性带来的汛期预泄风险问题,提出基于CFS预报产品的水电站水库预泄决策方法。利用CFS历史预报数据,建立不同预见期特定预报降雨条件下的实际降雨和入库流量的概率分布,计算不同库水位和发电决策组合下的弃水风险率。在常规调度的基础上,根据CFS降雨预报信息,以弃水风险率为决策依据,以优化的弃水风险率阈值为预泄幅度的定量指标进行调度。实例研究表明,该方法简便易行,充分利用了降雨预报信息,在汛期可提供定量化预泄决策,兼顾了效益与风险,达到了减小弃水的同时增大发电量的目的。     

水库长期发电优化调度的不确定性分析

为了解水库调度中不确定因素对水库长期发电优化调度的影响,以三峡水库为例,根据确定性系数与预报误差的关系对入库径流过程进行随机模拟,应用三角分布和正态分布描述水力不确定性的影响,不同时期选取不同的调度起调水位,运用动态规划法进行水库发电优化调度,将其结果与优化调度和常规调度结果进行比较,得出入库径流的预报误差、出库泄流能力和起调水位的变化等三个不确定性因素对水库长期优化调度的影响较大,而水位库容曲线的不确定性对结果的影响较小。并以确定性系数0.9、变异系数0.1和起调水位145m为例,综合考虑了各项不确定性因素对三峡水库长期发电优化调度的影响。结果表明,多年平均发电量减少0.94×108kW·h,这与三峡水库实际运行情况相符合。     

水库水沙多目标联合优化调度研究

针对水库运行中蓄水与排沙的矛盾,兼顾水库防洪、发电、航运及长期利用的综合运用目标,利用多目标决策方法建立了水库水沙多目标联合优化调度模型,即汛期采用分级流量原则控制水位运行,制定分级流量与对应的运行水位,通过水库发电调度与泥沙冲淤计算的耦合,计算在约束条件下水库的发电量、泥沙淤积量及长期综合效益。将该模型应用于三峡水库综合运行研究中,汛期按分级流量原则控制水位运行50年。计算结果表明,与原设计水位运行方式相比,汛期分级流量运行的综合效益增加6.324%、发电量增加5559%、泥沙淤积量仅增加0.148%,可见水沙联合调度的汛期分级流量运行方式能充分发挥三峡水库的综合效益。     

板桥水库汛限水位动态控制域研究

针对水库汛限水位动态控制域的确定为汛限水位动态控制研究的关键问题之一.结合入库流量信息、降雨预报信息等研究确定了水库泄流量分级情况下面临时刻允许控制的库水位值,根据绘制的面临时刻允许库水位值决策支持表,得出水库各级泄流量下的汛限水位动态控制域.实例应用结果表明,该方法考虑了水库汛限水位实时动态控制阶段下游防洪安全允许的各种泄流及其与区间洪水组合的情况,具有较强的可操作性和实用价值,可用于指导水库的实时防洪调度.     

基于POA优化的双江口水电站对下游梯级发电补偿效益研究

为分析大渡河双江口水电站补偿调节对其下游梯级电站的发电补偿效益,建立了发电量最大化兼顾最小出力最大化的中长期水库群优化调度模型,采用逐步优化算法(POA)求解模型,比较分析了有无双江口水电站补偿下的梯级发电情况,研究了双江口水电站对大渡河梯级的发电补偿效益。结果表明,双江口水电站对下游梯级的发电补偿效益显著,其补偿调节可增加大渡河双江口以下24个梯级多年平均发电量约31.2×108kW·h,增加多年平均枯水期电量约60.2×108kW·h,提升多年枯水期平均出力166.6×104kW,提升多年枯水期最小出力205.5×104kW;按照目前上网电价水平,并考虑分期分时电价的情况下,双江口水电站的补偿调节可增加其下游24个梯级收入共计19.101×108元(含税)。     

基于预报调度的河口村水库汛限水位动态控制域研究

开展实时预报调度是实现汛限水位动态控制的重要手段之一,构建了以削峰率最大为目标的水库实时防洪调度模型,提出了防洪库容分期动态使用的方法,选取河口村水库历史洪水及百年一遇洪水过程,通过实时预报调度仿真,在保证足够安全裕度的条件下,确定了河口村水库汛限水位动态控制值的上限为250m,在不增加防洪风险的前提下,多场次洪水平均可增加的洪水资源利用量为4 070×104 m3。     

基于模糊推理的大伙房水库防洪调度方式研究

针对防洪调度方案生成为调度中的难点,以大伙房水库为例,结合调度实践经验,构建了基于模糊推理的水库防洪调度模型,研究了基于综合信息的水库防洪调度方式,通过不同频率设计洪水模拟调度,制定了基于未来24 h降雨预报、净雨预报、水库实时水位等面临时刻综合信息的模糊推理规则.模拟结果表明,该方案合理可行,为决策者提供了依据.     

洪水调度关键期提高碧流河水库防洪能力的方法

基于预报信息的可利用性分析,研究了洪水调度关键期利用可回充水量进行预泄以降低设计汛限水位的方法,该方法利用降雨与退水预报信息计算回充水量,依据回充水量预泄,合理地设计降低设计汛限水位。碧流河水库2012年50年一遇洪水调度过程表明,应用该方法洪水调度关键期设计汛限水位降低0.39m,调洪最高水位降低0.24m,最大泄量减少了190m3/s;同时调洪末水位仍能达到主汛期末允许控制水位68.8m,既提高了该水库防洪能力,又保证了后期兴利效益,亦为其他水库防洪调度提供了借鉴。     

Evaluation of micro‐scale electricity generation cost using biomass‐derived synthetic gas through modeling

A promising renewable energy technology is electricity generated with biomass‐derived synthetic gas (syngas). The economic feasibility of using biomass gasification for generating electrical power is very much dependent on the cost of the power plant and the cost of its operation. A cost model was developed to analyze the Unit Cost (unit‐cost) of electricity generation from micro‐scale power facilities that used biomass gasification as its energy input. The costs considered in the model were capital cost and operating costs. The results from the modeling indicated that operating cost was a major part of the total annual production cost of electricity generation, and that labor was the largest part of the total annual production cost of operation, and it was during the time when the power facilities operated at lower generation capacity levels. One effective way of reducing the unit‐cost was to operate the facility at high capacity level. The study found that when the capacity level increased the total of annual cost was also increased, but the electricity unit‐cost decreased markedly. For a given level of generating capacity, the electricity unit‐cost of the facility operating at a two or three shifts operating mode was significantly lower than that of one shift operating mode. Copyright © 2010 John Wiley & Sons, Ltd.     

Comprehensive methodology for identifying tariff zones of efficiency of hydrogen-thermal accumulation system at the NPP

In countries with developed nuclear energy, there are problems associated with non-uniformity of the daily electricity load, due to the economically justified need to load nuclear power plants with a maximum installed capacity utilization factor. This is due to the cheapness of nuclear fuel compared to organic and, at the same time, high investment compared to thermal power plants, as well as the presence of technological limitations on maneuverability. Most organic fuel thermal power plants are switched to half-peak mode, which negatively affects their efficiency and reliability.In addition, the ever-increasing requires on the level of safety negatively affect the economic competitiveness of nuclear power plants. Improving safety through the introduction of passive heat removal systems of the reactor core is provided for in new NPP projects. These systems have several disadvantages: maintenance costs; a significant increase in capital investment; emergency cooling mode.To solve these problems, the authors developed a system of hydrogen-thermal accumulation, which, when combined with a nuclear power plant, allows one to accumulate cheap energy during the hours of a decrease in load in the power system due to electrolysis of water to produce hydrogen and oxygen, and thermal accumulation of hot water in heat-insulating tanks. Thanks to the use of hot water tanks, investment in the accumulation system is significantly reduced. Thanks to the use of a hydrogen-oxygen steam generator, the opportunity to generate an additional main steam and to use it in the additional steam turbine unit appears, which will allow to avoid costly modernization of the main equipment of the nuclear power plant and reducing its lifetime. The presence of a low-power steam turbine unit as part of the accumulation system ensures uninterrupted autonomous power supply to consumers of the NPP own needs due to the possibility of using the energy of the reactor residual heat, when the station is completely blackout. The method of combining the hydrogen complex with thermal accumulators is completely new and has no analogues.The economic efficiency of the developed energy complex has been investigated. The accumulated net present value was determined depending on the off-peak electricity tariff for the three options of the half-peak electricity tariff, taking into account possibility to refuse expensive heat exchangers of the passive heat removal systems. It is shown that the use of the proposed scheme is advisable in regions with off-peak electricity tariffs in the range 0–0.32 cents/kW·h, 0–0.8 cents/kW·h and 0–1.25 cents/kW·h, respectively, depending on the forecast dynamics of the half-peak electricity tariff. The average payback period of the accumulation system for given conditions is equal to 3–15 years.     

基于气象因子的汛期径流预报模型

针对现有汛期径流预报方法的缺陷,从物理成因出发,采用投影寻踪方法从74项大气环流因子中筛选出影响汛期总径流量的主因子,结合汛期前期降雨量进行相似分析获取相似年份,构建基于气象因子的汛期径流预报模型。以长江流域关键断面汛期来水预报为例开展了模型的实例研究,结果表明,该模型考虑了气象因子对长期径流变化的影响,对汛期总径流量的预报以及汛期月径流预报的精度均高于门限回归模型,是汛期径流预报的一种行之有效的方法。     

Heating Characteristics and Economic Analysis of a Controllable On-Demand Heating System Based on Off-Peak Electricity Energy Storage

The working principle of a controllable on-demand heating system based on off-peak electricity energy storage(COHSBOEES) is as follows: the cheap off-peak electricity energy is converted into heat energy for storage in the evening, and the heat energy can be extracted on demand for heating during daytime peak or flat electricity periods. This technology can promote the smooth operation of the power grid, solve the problem of peak regulation for the electrical network, and promote renewable energy consumption. Based on the controllable on-demand heating strategy, a COHSBOEES for a heating area of 1000 m^2 was designed and built. Variations in the energy consumption and operating cost of the COHSBOEES in different heating situations were analyzed. The results showed that, off-peak electricity energy storage for heating was energy saving in comparison with central heating when the heating intensity of the COHSBOEES was 70 W/m^2 and the on-demand heating rate was less than 73.0%, and the off-peak electricity energy storage for heating was energy saving at any on-demand heating rate when the COHSBOEES had a heating intensity of 50 W/m^2. After the COHSBOEES has been running for three complete heating seasons, when the off-peak electricity price was 0.25 yuan/kW·h, the energy consumption cost of the COHSBOEES can be saved by 77.6% in comparison with central heating.     

ENSO事件影响下长江大通站汛期径流预测建模分析

从环流指数和ENSO事件指数出发,考虑到大尺度环流系统和海温影响的长期性,使用滑动平均方法对预报因子做前期处理,计算了预报因子在2、3、6月尺度的滑动平均值。在此基础上采用BP神经网络建立了长江大通站汛期径流预测模型（BP-Pre）,重点对ENSO事件影响下的径流极值进行预测。为验证模型可行性,采用均生函数模型和利用传统因子建立的BP模型（BP-Ori）作对照分析并进行精度评价。结果表明,部分因子在滑动平均处理下Spearman秩相关系数得到提高;历史平均上,大通站汛期径流与前年发生的ENSO事件关系密切;事件类别不同,对应径流也相对偏大或偏小;BP-Pre模型在率定期拟合效果不及均生函数模型和BP-Ori模型,但从多方法综合评价分析来看其检验期的预测精度更高,对径流极值预测更为精准。