电力期货与期权交易对水电商的风险规避作用

针对水电厂受电力市场电价波动与来水量不确定性的影响，设计了简单的水电厂风险管理案例。将期货与期权的交易模式运用于电力市场中，水电商可以利用期货的套期保值功能规避风险，让购电商和投机商分担电价风险；水电商也可以通过购买看涨或看跌期权，保证水电厂合约外的剩余电量在期望价格销售，减少弃水。     

基于用户价格响应和满意度的峰谷分时电价决策模型

峰谷分时电价是电力需求侧管理(DSM)的重要手段之一，合理地制定峰谷电价水平是其实施的关键。在了解用户实行的峰谷电价历史数据的基础上，提出建立用户的电价响应矩阵以反映用户对峰谷分时电价的响应;并建立用户满意度模型，综合考虑用户用电方式的满意度和电费支出的满意度。给出了基于用户价格响应和满意度的峰谷分时电价优化决策模型。最后给出一大工业用户数据验证了文中方法的有效性。     

考虑电力市场参与风险的抽水蓄能电站优化运营策略

随着可再生能源的比例不断增大,新型电力系统对抽水蓄能这类灵活性资源的需求也逐渐增强。为了促进抽水蓄能电站的投资积极性,市场化的价格机制逐渐健全,但是电价的波动也会使市场化收益具有风险性。在考虑电力市场价格波动的情况下,针对抽水蓄能电站提出了一种基于条件风险价值模型的电能量市场与辅助服务市场联合优化运营策略模型。首先对电力市场价格进行预测,通过抽样、聚合形成典型的电价场景。之后,根据所提的运营策略模型得到不同市场的容量分配结果,并结合抽水蓄能电站的实际情况进行算例分析,验证模型规避风险的有效性。最后,分析了不同的风险偏好以及市场价格对电站收益的影响。结果显示：所提策略在不同电价波动场景中的收益波动量相比传统策略减少了17.2%,且能累计获得76.23万元风险规避效益。风险偏好因子取最小与最大时,预期收益仅相差10.08万元。结果表明：考虑电力市场参与风险的抽水蓄能电站优化运营策略能有效规避市场价格波动风险,能获得更为稳定的预期收益。     

电力市场环境下园区分布式能源售电商运营服务设计

随着我国电力体制改革的推进,分布式能源、大型工业园区、大型居民集聚区等都将成立售电公司,并为用户提供售电、能效服务、需求响应等多样化服务。园区售电公司作为需求响应负荷集成商,将具有需求响应能力的不同负荷特性的用户集中,代表用户参与批发市场,获得优惠的用电价格,节约用户交易成本;同时,售电公司为用户订制各类电价套餐,引导用户合理用能,平滑负荷曲线,提高电力设备利用效率。售电公司开展增值业务,向用户提供合同能源管理、综合节能和用能咨询等服务而获得利润。对售电商关键业务进行了分析,为电力市场改革进程中售电商潜在风险提供应对预案,为售电商提供运营服务模式借鉴。     

基于分位数的CVaR方法在水电多风险分析中的应用

提出了一种基于分位数的条件风险价值（CVaR）方法，以各期CVaR的绝对偏差加权和最小为目标函数建立数学模型，针对水电在上网竞价过程中面临的电价、来水、需求等各类营销风险，在蒙特卡罗模拟条件下，给出相应的发电收益率表达式，对模型进行扩展。该模型可同时应用于计及风险的发电量时间分解和空间分配计算，以完全市场模式下水电厂年发电量在各月多个市场中的分解为例，说明该风险度量指标的可行性和实用性。     

计及需求侧价格弹性的电源投资动态仿真

电力商品需求侧的用户响应非常有限,但在市场环境下,即使较小的弹性也有助于缓解供需紧张的局面,对于削减非经济负荷和保障供电可靠性有着重要意义。文中量化分析了电力市场需求侧的价格弹性因素对于供需均衡的影响作用,以及价格弹性与市场实时需求之间的动态关系。进一步在计及需求弹性的基础上,建立了电源投资的动态仿真模型,并通过实际算例对比分析了 2类典型情景下的电源投资发展趋势,证实了模型的有效性。     

竞争电量比例对中长期电力市场价格的影响分析

在单一购买方的发电侧电力市场中，大规模电量在中长期合同交易市场中集中竞价，使得市场可能面临巨大的市场风险。从分析中长期合同交易竞争电量比例参数、年度合同（双边交易）电量比例对价格形成机制的影响入手，深入研究了通过合理配置竞争电量比例参数来保证市场价格竞争性形成机制的方法。利用发电公司必须运行率指标，充分考虑竞争者地位、市场供需形势以及机组实际可用情况等因素来评估发电公司对市场价格形成有效竞争性的影响，提出了一种合理配置中长期合同交易模式下的竞争电量比例的计算模型和分析方法。通过算例验证表明，该模型得到的竞争电量分配比例可以保证在中长期合同交易中任何发电公司不具备对任意申报电量任意定价的能力，从而保证市场价格形成的有效竞争性。     

电力市场中预测问题的新内涵

传统的负荷预测是电力系统规划与运行的基础工作，电力市场化的改革对负荷预测提出了更高的要求，赋予其新的内涵。文中探讨了电力市场中的预测问题，分别针对发电侧竞价和用户侧开放的电力市场，提出了一些新的预测内容和预测思想，包括扩展短期负荷预测、连续多日负荷曲线预测、电力市场价格预测、市场风险预测与评估、考虑需求侧管理影响的电力需求预测、用电需求曲线预测、基于价格弹性的需求预测等，指出了这些预测问题的研究热点和难点,探讨了未来的主要研究方向。     

尖峰电价决策模型分析

尖峰电价（CPP）是电力市场下需求响应的重要手段之一。作为一种灵活的电价机制，制定合理的CPP实施策略并选择合适的尖峰日是其成功的关键。文中在分析CPP费率体系和实施过程的基础上，利用电量电价弹性矩阵来反映用户对CPP的响应，采用复合电价模型来预测电力批发市场电价，由此建立了一种兼顾用户和供电公司利益的CPP决策模型，并利用0-1整数规划进行求解。最后通过算例仿真验证了所述方法的有效性。该方法有利于节省用户的电费支出、降低供电公司的购电费用以及规避批发市场的购电风险，实现多方共赢。     

华东区域市场月度购电决策模型实证比较

华东区域电力市场中，电力公司在月度市场中报价，日前市场中只申报负荷需求，以管制价格对用户售电。各个市场中竞价电量的分配以及报价直接影响到电力公司的收益和市场稳定。文中基于投资组合理论，对电力公司考虑风险的月度购电策略进行了研究。首先对3种风险计量指标的购电决策模型从实际应用角度进行了分析，其中基于半方差的购电模型为首次提出;其次针对购电侧分段报价规则，提出了利用分段降低风险的月度分段报价模型;最后结合实际数据对各种模型进行了实证分析。     

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。     

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.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Desiccation and recolonization of phytobenthos in a regulated desert river: Colorado River at Lees Ferry,Arizona, USA

We tested the recolonization of the phytobenthic community in the tailwaters of Glen Canyon Dam following long- and short-term experimentally induced desiccation. The response of Cladophora glomerata, Oscillatoria spp., miscellaneous phytobenthos species and periphyton was studied over 18 weeks using three treatments: (1) undisturbed control cobbles from the submerged zone; (2) cobbles desiccated and replaced into the submerged zone; and (3) cobbles desiccated and replaced into the varial zone. Periphyton density and compositional response resulting from these treatments were also examined. Desiccation treatments were significantly different in biomass from controls throughout the study. The biomass of desiccated and replaced river cobbles averaged <30% of the controls for C. glomerata and periphyton during the 18-week recolonization period. In contrast, the biomass of the control Oscillatoria and miscellaneous phytobenthos species averaged only 3 and 50% of that in the desiccation treatments, respectively. Cladophora, the dominant alga, comprised 77% of the phytobenthic biomass. A significant positive relationship between discharge, Cladophora and periphyton biomass was present in all treatments, while there was a negative relationship with discharge for Oscillatoria and miscellaneous phytobenthos species. There was a significant inverse correlation, as well as a pattern of separate biomass dominance, between C. glomerata and Oscillatoria. Cladophora was the dominant phytobenthos species on cobbles below the baseflow and Oscillatoria was dominant on cobbles in the varial zone. In general, the Cladophora biomass decreased under intermittent drying conditions, while Oscillatoria declined under permanently wet conditions. Diatom composition was not significantly different between treatments; however, their density was lower on desiccated cobbles. Diatom density on desiccated cobbles in the submerged and varial zones averaged 69 and 42% of that of the controls, respectively. Recovery and maintenance of benthic resources are hindered by fluctuating flow regimes driven by electricity and irrigation requirements. Repeated desiccation of the phytobenthos has major effects on the bottom-up interactions in the Colorado River ecosystem. © 1998 John Wiley & Sons, Ltd.