QLY2150型风电起重机电控系统设计

针对中国风能市场的发展需要,研制开发的QLY2150型大型特种专用风电起重机的电控系统均采用总线通讯方式,具有自动化程度高、高效、安全等特性,为起重机提供了良好的电控系统支持,并为以后特种专用起重设备电控系统设计提供借鉴。     

弦弓式预应力柱面网壳结构风洞试验及风致效应研究

弦弓式预应力柱面网壳结构是一种新颖的结构形式,通过对网壳下部拉索施加预应力使结构成为自平衡体系,某火电厂干煤棚为弦弓式预应力柱面网壳结构在干煤棚结构中的首次应用,风荷载是其主要荷载之一,目前规范对该类网壳结构的体型系数未作明确规定,因此需要进行风洞试验来确定其体型系数,试验考虑了网壳周边环境的作用,严格模拟了规范规定的大气边界层风场,分析研究了网壳表面风压分布规律及其影响因素,给出了可供设计采用的体型系数,同时进行了风致效应的研究,研究表明,周边环境对网壳表面风压分布的影响较大而煤堆的影响较小,大气边界层风场中风速脉动导致的风压改变在设计时已不容忽视,风荷载对网壳下部预应力拉索应力起着卸载作用,各索的最大应力减少比例在20％左右。     

浙江天台山风电场设计

介绍了浙江天台山风电场的区位优势,对风力发电机的选型和布置进行了研究,探讨了电气与土建设计方式,研究了风电机组的运输与安装方法,并针对风电场运行出现的问题提出了改进对策,指出经过改进维护,全部风机进入正常运行发电状态。     

Efficient pricing for European electricity networks – The theory of nodal pricing applied to feeding-in wind in Germany

This paper applies nodal pricing as an economic approach to efficient use of electricity networks utilization for the fairly large German grid. We combine a straightforward welfare maximization with the technical specificities of electricity flows on a realistically large network. The nodal pricing model is applied in order to analyze the impact of extended German wind power production on the power grid. The paper shows that economic modeling, taking into account physical and technical constraints, makes important contributions to the assessment and optimization of system configuration and operation.     

Effects of grid curtains on the wind loads of a high‐rise building

The effects of grid curtains on the local and overall wind loads of a high‐rise building are investigated in detail according to a series of wind pressure and wind force tests on rigid model in a wind tunnel. The effects of grid curtains on the mean and fluctuating wind pressures on windward and sideward walls when the wind direction is parallel to the geometrical axes are investigated, along with the effects of the most unfavorable wind pressures for all wind directions. Furthermore, the effects of grid curtains on the mean and fluctuating aerodynamic forces on the entire building are also analyzed for various wind directions, along with the effects of grid curtains on the aerodynamic force spectra when the wind direction is parallel to the geometric axes. The test results indicate that grid curtains affect the mean and fluctuating windward pressure slightly but greatly influence the large sideward negative pressures. Grid curtains increase the mean and fluctuating windward aerodynamic forces and reduce the fluctuating aerodynamic torsions. According to the aerodynamic force spectra, grid curtains can mainly affect the wind forces in the low‐frequency range. Copyright © 2015 John Wiley & Sons, Ltd.     

Ten questions concerning integrating smart buildings into the smart grid

Recent advances in information and communications technology(ICT) have initiated development of a smart electrical grid and smart buildings. Buildings consume a large portion of the total electricity production worldwide, and to fully develop a smart grid they must be integrated with that grid. Buildings can now be"prosumers"on the grid(both producers and consumers), and the continued growth of distributed renewable energy generation is raising new challenges in terms of grid stability over various time scales. Buildings can contribute to grid stability by managing their overall electrical demand in response to current conditions. Facility managers must balance demand response requests by grid operators with energy needed to maintain smooth building operations.For example, maintaining thermal comfort within an occupied building requires energy and, thus an optimized solution balancing energy use with indoor environmental quality(adequate thermal comfort, lighting, etc.) is needed. Successful integration of buildings and their systems with the grid also requires interoperable data exchange. However, the adoption and integration of newer control and communication technologies into buildings can be problematic with older legacy HVAC and building control systems.Public policy and economic structures have not kept up with the technical developments that have given rise to the budding smart grid, and further developments are needed in both technical and non-technical areas.     

曹妃甸煤堆防风网架气弹模型风洞试验

目前复杂网架结构风荷载通常采用刚性模型风洞试验确定,但由于忽略了结构与流体之间的耦合效应,其结果与实际结构存在偏差。气弹模型则可真实反映结构在自然边界层中的响应,但由于网架结构非常复杂,需要适当简化相似准则和选择结构主要响应振型进行设计。基于曹妃甸煤堆防风网架结构,设计1颐50气弹模型。通过应变片测试支架根部内力,得到了B类风场不同风速下网架内力风振系数;通过激光位移计测得顺风向位移响应,求得结构顺风向位移风振系数。最后比较分析了两类风振系数,为同类结构气弹模型设计制作和风振系数计算提供参考。     

Testing of low-voltage ride through capability compliance of wind turbines – a review

The increasing grid integration of wind power has led to the compulsory requirement of low-voltage ride through capability (LVRT) in wind turbines. Grid codes for LVRT capability of wind turbines are proposed in all major wind-energy-producing countries. The testing of LVRT capability compliance of the wind generators as per the specified grid codes during different fault conditions is essential to ensure its reliability. The testing process is generally done by the manufacturers and crucial for certification as per the IEC 61400-21 international standard for measurement of power quality characteristics of wind turbines. This review analyses the various testing tools under the software- and hardware-based categories. The review helps in understanding the present challenges in implementation of wind turbines, to alleviate the difficulty in LVRT testing procedures.     

Davenport风速谱与Kaimal风速谱在通讯塔设计中的比较分析

本文对Davenport风速谱和Kaimal风速谱进行了分析比较,并且以江苏某通讯角钢塔为例,采用两种不同的风速谱计算了结构的风振响应,得出了在通讯角钢塔的工程计算中Kaimal风速谱更加接近实际风速时程的结论。     

风场大涡模拟中网格非匹配算法

计算风工程中对风场进行大涡模拟是从流体角度诠释风压产生、发展、分布的数值方法.风场需分割为多个子块,并根据风活跃程度分别指定不同的网格密度,在各块界面上网格非一一匹配.本文针对:三维子块,提出了一种搜集非匹配信息的算法,用以计算子块间的风流体通量.根据结构网格规律性,将公共界面上两个子块的网格线合并为一套网格,从而将公共界面划分为小面,形成联接信息进行全场联立求解.典型算例表明可在节省计算资源的同时保证精确性,同时实现网格密度平滑过渡,为大跨度结构风场模拟解决了一个基础问题.     

Wind and structural modelling for an accurate fatigue life assessment of tubular structures

Based on the joint probability with regard to wind speed and its main direction, the current paper presents a practical and efficient approach for calculating wind induced fatigue of tubular structures, the effects of the wind direction, across wind and wind grid size on the high cycle fatigue of the structure are addressed. In each time step of the dynamic response calculation, the large deformation effects and the wind induced drag forces due to the updated structural deformations are taken into account. It is found that, the directional wind effects on the fatigue damage mainly depend on the orientation of the structure, the location and the support condition of the selected joints, and the relative probability of occurrence for the high winds speed in each direction, etc. Furthermore, the across wind components are proved to be a significant contributor on the fatigue damage and cannot be ignored. The fatigue damage is also found to be rather sensitive to the wind grid size for generating the wind fields. It is also concluded that vibration of each individual member interacts with the global dynamic response and the wind loading, and a fatigue check should therefore be against both individual member and global response. The wind fatigue calculation procedure presented in the current paper has the merit of reducing uncertainties without degrading a required safety level, this may lead to a positive economic impact with regard to construction and maintenance costs. It has been applied on quite a few industry and research projects and can be widely applied on the similar study of structures.     

Smart imposing of operational limits in optimising the technical and economic indexes of a distribution network in the presence of distributed generation sources

ABSTRACT

Optimal placement of distributed generation sources in order to enhance the technical and economic indexes of the distribution network maximally is one of the problems for which very diverse solutions are competitively developing. Each of these methods tries to reach a more optimum point by choosing a number of objective functions from economic and technical indexes and applying a number of common limits of the electricity grid. Little attention has been paid to the extent of practicality of implementation of these optimum points on a real network with limits imposed by set up condition of distributed generation sources and the common electrical limits. In this paper, depending on the grid's environmental conditions, a method is proposed to smartly impose limits regarding operational conditions in maximally optimising the technical and economic indexes of a distribution network in the presence of distributed generation sources. The firefly nonlinear smart algorithm is utilized for smart optimisation and the impact of operational limits in optimal placement of a wind turbine and the extent of enhancement in economic and technical indexes of the studied grid is investigated graphically.     

Impact on power quality due to large-scale adoption of compact fluorescent lamps – a review

The demand of electrical energy has grown tremendously in the last couple of decades across the globe. The energy conservation and management has attracted the attention of stake holders for efficient utilisation of the resources. One of the major steps taken by the authorities towards conservation of electrical energy is replacement of incandescent lamps (ILs) by compact fluorescent lamps (CFLs). CFL uses electronic circuit for its ignition, making them a non-linear load on utility grid. Large-scale replacement of ILs has enormous effects on utility grid in terms of power quality. This paper reviews the work conducted by several researchers investigating the effect of using CFLs on power quality. Basic terminologies related to power quality is defined. The experimental results elaborate the pollution on the grid in the term of total harmonic distortion in current due to adoption of CFLs. The methodologies of harmonic measurement system are reviewed. Different software used for the analysis is presented. The paper will help the researchers to receive a comprehensive overview of power-quality issues.     

国家博物馆高低压供配电系统组成

本文主要介绍了国家博物馆高低压配电系统的组成,高低压接线方式及电源等级,高、低压开关连锁保证了供电的可靠性。三路市电高压侧分段运行,市电和自备柴油发电机组用于主电源与应急电源之间的自动切换组成了自动应急供电系统。     

Spatiotemporal analysis of the impact of electric vehicle integration on Reykjavik's electrical system at the city and distribution system level

This case study analyses the potential additional electrical load on Reykjavík's electrical grid spatially and temporally (2019–2050) due to the integration of electric vehicles (EVs) according to different pro-EV policies. A cost estimate of the required upgrades is provided. The results of the research show that the electrical system could face strain with a potential peak load increase of 67–114% over the study period. Spatiotemporal analysis can thus aid policymakers and grid planners in understanding where and when the electrical system could be put at risk due to EV charging and plan accordingly.     

风致不均匀积雪的大跨网架结构工作状态分析

为了保证结构服役安全,有必要对不均匀积雪荷载作用下网架结构工作状态进行分析。采用CFD数值模拟技术,基于准动态网格划分方法,以一正放四角锥网架结构为研究背景,分析了网架结构在持续降雪24 h中的屋面不均匀积雪分布变化情况,并详细探讨了不同风向角和不同风速对网架屋面积雪分布变化情况的影响; 最后建立了该网架结构的有限元模型,分析了不同雪荷载工况的结构工作状态。结果表明:与其他有风条件下的工况相比,风速为12 m?s^-1、风向角为90°时的结构屋面平均雪压和积雪沉积区域占比最大,因此它是结构的最不利工况,该工况的平均雪压是无风条件下均布积雪平均雪压的88.9%,但结构杆件的最大应力值及挠度值却较均布积雪作用时有所增加,而且部分杆件从受拉杆变为受压杆; 风致不均匀积雪是网架结构在服役期间的安全隐患,应在工程设计中予以重视。     

通信角钢塔脉动风荷载模拟及风振响应分析

针对作用于通信角钢塔的风荷载特点,将风荷载中脉动风视为平稳的高斯随机过程.从随机理论出发,考虑空间相关性,采用谐波合成法模拟出脉动风荷载的时程曲线.所采用的人工模拟风速时程曲线可应用于一般高耸结构的脉动风荷载模拟,符合风速随机过程的一般统计特征且具有很好的随机性.最后以通信角钢塔为工程背景,建立有限元模型,采用ANSY...     

关于住宅电气设计的几点看法

住宅的功能完善与发展离不开电气,电气也决定了住宅建筑的现代化程度。住宅是重要的民生话题,因此很多专家和学者或多或少都关注了住宅的电气设计问题。本文阐述了住宅电气设计的基本要求,并结合在设计院和甲方的多年工作经验,提出了自己的一些看法,以供交流和探讨。     

Modeling of topographic wind speed effects in Hawaii

Terrain or topographic amplification of wind speed has been a significant contributing factor in the past hurricane loss experiences of Hawaii and various islands in the Pacific region, such as Guam and American Samoa. In Hawaii, where the real terrain is very complex, the actual magnitude and extent of speedup can be quite different from current building code formulas. To address this issue pertinent to both loss estimation and structural design in Hawaii, regional scale models of selected developed portions of the Hawaiian Islands have been constructed and tested in a boundary-layer wind tunnel to determine wind velocity accelerations and decelerations due to topographic influence over a grid of data acquisition locations. Influences of terrain, directionality, channeling, and topographic features have been identified. Wind-tunnel test data were utilized to develop empirical models for peak, and mean wind speed-up based on spatially weighted parameters derived from a Digital Elevation Model raster grid of terrain and relevant categorical landform variables. A geographic information system was then used to provide detailed contouring of the wind flow speed-ups. This provided a micro-zoned mapping of directional wind speed-up factors relative to the speed at a flat open coastal site.     

State-of-the-art research on micro grid stability: a review

The usage of renewable energy resources (RES) in energy is receiving great attention as a solution to the problem of a shortfall in electrical energy. Application of RES in a generation system is done with diverse outlines, amongst others in a micro grid system. Employment of micro grid systems offers numerous benefits both for the consumer as well as for the utility provider. Voluminous micro grid expansions are carried out in more than a few countries, because it offers healthier power quality and furthermore it is ecologically friendly. Even though its adoption is growing steadily, there are still several hurdles to proficiently design, regulate, and operate micro grids when linked to the grid, and as well when in the islanded mode, and wide-ranging investigation activities are on-going to confront the issues. It is essential to consider across-the-board opinions of the micro grid amalgamation in a power system network. This paper presents a review of issues in relation to micro grid stability and offers an account of study in areas related to micro grids.