一种基于云边协同的电力业务时延优化方法

随着电力物联网技术的不断发展,新兴的多业务场景不断涌现,对电力大数据量业务的时延提出了新的挑战.文章针对物联网云架构,提出了一种基于软件定义网络的云边协同时延优化方法,以最小化系统平均时延为目标,通过引入一个连续可变的云、边任务分割系数,将时延优化问题转化为凸优化问题,并在此基础上最终得到了优化的任务分割策略.实验结果...     

面向大数据处理的数据中心节能调度策略研究

基于多副本的分布式存储是数据中心的主要数据存储方式,为应用提供可靠、高效的数据读取服务.针对当前日益增多的大数据分析应用,以及频繁数据读取带来的较大能耗等问题,文章分析异构存储系统数据读取能耗的差异,提出面向大数据处理的异构存储节能调度问题(Energy Reduction problem on Heterogeneo...     

电力大数据平台研究与设计

电力大数据平台定位为数据共享平台、数据分析应用平台、大数据应用开发运行平台,从数据采集、存储、预处理、计算、分析、可视化等多个层面为数据分析人员、大数据应用开发人员提供服务。文章分析了电力大数据平台应用需求,详细设计了电力大数据平台的应用架构、技术架构和数据架构,并对电力大数据平台的多源异构数据融合技术、异构数据并行处理技术、基于工作流的任务调度技术等关键技术进行了研究,最后针对电力大数据平台下一步的研究思路、重点和方向提出了建议。     

云边协同体系下水电厂统一数据平台研究与应用

以大型发电集团数字化转型为应用背景,文章提出发电集团云边协同体系架构,并结合数字水电厂智能辅助决策、人机协同等需求,研究和设计云边协同体系下数字水电厂统一数据平台,详细阐述虚拟化、数据中心、基础服务等内容,同时结合具体应用实例探讨了云边协同体系下水电厂统一数据平台与业务应用的关系.所提的统一数据平台技术架构适用于发电集...     

基于PDMiner大数据挖掘平台的电力系统安全评估及故障诊断系统

电力系统中的数据复杂多样,电力大数据的挖掘处理是电力公司面临的难题之一。阐述了电力大数据发展现状,将电力云概念引入到电力系统大数据分析之中,提出了基于云计算理论的大数据挖掘平台PDMiner,介绍了其整体架构和原理,针对电力大数据的平台架构和关键技术,开发了一套基于PDMiner平台的电力系统安全评估与故障诊断系统,该系统配置在SCADA/EMS的数据管理子系统上,提高了数据处理的效率,并且能准确提取到故障类型、风险区域等数据背后的准确信息。     

基于电力物联网的数据智能检测模型研究

为支撑电力物联网数据共享,发挥电网数据价值,文章针对当前电力物联网数据平台中存在的技术组件多样、应用难度大、检索数据困难、数据应用门槛高和数据模型管控机制不完善等问题,优化电力物联网数据平台整体框架,提出基于孤立森林的量测类实时数据质量异常检测及改进算法,通过抢修故障研判和停电故障研判2个场景仿真验证数据质量检测算法的...     

虚拟电厂下基于基因表达式编程的云边协同分布式异常数据检测算法

数据可靠互联对虚拟电厂中各类能源生产、传输以及调度等环节的安全稳定运行至关重要。然而人为失误、采集设备故障、网络恶意攻击等因素导致虚拟电厂各环节业务系统中异常稀疏数据频繁产生。现有基于统计学或机器学习的集中式异常数据检测方法存在依赖数据分布和先验知识、计算复杂度较高、效率低下等缺陷。为了解决上述问题,文章提出一种虚拟电厂下基于基因表达式编程的云边协同分布式异常检测算法。首先,基于云边协同机制,构建虚拟电厂云边协同分布式异常检测体系架构;其次,从算法原理、基于最小二乘的全局异常检测模型生成等方面设计基于基因表达式编程的分布式异常检测算法。基于3个真实数据集和3个开源数据集的仿真实验结果表明,与现有模型相比,提出的算法在异常数据检测的准确率、漏检率、误检率、平均耗时以及加速比方面均具有明显的优势。     

基于效用函数的电力物联网异构网络接入QoS保障方法

随着电力物联网的发展,越来越多的通信接入方式被加入到智能配电网中,网络之间相互覆盖,相互重叠,现有的QoS保障方法已无法满足未来智能电网新业务的多样化需求以及异构网络的切换与统一问题所带来的挑战。提出了一种基于效用函数的电力物联网异构网络接入QoS保障方法。首先构建了效用函数评价模型,设计了评价参数,并给出了参数的效用函数。其次,设计了接入网络映射算法。最后,通过仿真实验,验证了基于效用函数的异构网络接入QoS保障方法在电力物联网背景下的性能与可靠性。     

基于云计算技术的电力大数据分布式检索系统

为了提高电力大数据定位识别和信息融合能力,进行电力大数据检索优化设计,提出一种基于云计算技术的电力大数据检索系统设计方法,采用多元回归分析方法构建电力大数据库存储结构模型,进行电力大数据的分布式存储数据结构特征分析,对混合型的电力大数据在云计算环境下进行信息聚类融合处理,采用模糊特征分组聚类方法对不同属性的电力大数据进行分组检测,提取电力大数据的关联规则特征量,采用云计算技术实现电力大数据分布式检索。在嵌入式环境下进行电力大数据分布式检索系统软件设计。仿真结果表明,采用该方法进行电力大数据检索的特征指向性较好,数据检索的数据召回率较高。     

面向能源互联网智能感知的边缘计算技术研究

随着能源互联网建设的持续推进,大量的传感器接入到系统中,获取的感知数据是海量级的,导致系统传输压力大、主站计算负荷重。传统的传感信息获取处理方式存在数据良莠不齐、数据缺失、格式不统一的问题,引入边缘计算技术定义了智能感知的系统框架,就地实现数据的处理与判决,通过云边协同机制优化系统设计。文章首先给出了多参量智能感知数据优化传输方法,其次提出了面向多参量感知的边缘计算算法的设计方法,涉及数据统一、数据辨识、分布式群智几方面,最后落地在输电线路巡检,在微风振动、舞动分析、增容设计、视频分析、云边升级等方面做了尝试。     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

Contents in Volume 23,2014

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Assessment methods of material ageing using Sdobyrev''s creep rupture model

The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σ_red = σ₁ β + (1 − β)σ_i, where: σ₁-maximal principal stress, σ_i-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures.     

Production of hydrogen from sewage biosolids in a continuously fed bioreactor: Effect of hydraulic retention time and sparging

Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H₂ kg⁻¹ VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min⁻¹ successfully prevented a decline in hydrogen production and resulted in a yield of 27.0  L H₂ kg⁻¹ VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production.     

汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.