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Analysis on running safety of train on the bridge considering sudden change of wind load caused by wind

Tian ZHANG, He XIA, Weiwei GUO

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 558-567 doi: 10.1007/s11709-017-0455-1

摘要: The calculation formulae for change of wind load acting on the car-body are derived when a train moves into or out of the wind barrier structure, the dynamic analysis model of wind-vehicle-bridge system with wind barrier is established, and the influence of sudden change of wind load on the running safety of the train is analyzed. For a 10-span simply-supported U-shaped girder bridge with 100 m long double-side 3.5 m barrier, the response and the running safety indices of the train are calculated. The results are compared with those of the case with wind barrier on the whole bridge. It is shown that the sudden change of wind load caused by wind barrier has significant influence on the lateral acceleration of the car-body, but no distinct on the vertical acceleration. The running safety indices of train vehicle with sectional wind barriers are worse than those with full wind barriers, and the difference increases rapidly with wind velocity.

关键词: wind barrier     sudden change of wind load     dynamic response     running safety     comfort    

Distribution of background equivalent static wind load on high-rise buildings

Jianguo ZHANG , Ming GU ,

《结构与土木工程前沿(英文)》 2009年 第3卷 第3期   页码 241-248 doi: 10.1007/s11709-009-0036-z

摘要: In this paper, the along-wind and cross-wind fluctuating load distributions along the height of high-rise buildings and their correlations are obtained through simultaneous pressure measurements in a wind tunnel. Some typical methods proposed in some relative literatures, i.e., load-response correlation (LRC), and quasi-mean load (QML) and gust load envelope (GLE) methods, are verified in terms of their accuracy in describing the background equivalent static wind load distribution on high-rise buildings. Based on the results, formulae of the distribution of background equivalent static load on high-rise buildings with typical shapes are put forward. It is shown that these formulae are of high accuracy and practical use.

关键词: high-rise buildings     along-wind     cross-wind     background equivalent static wind load     close formulae    

一种针对测试误差、参数误差和负荷突变故障分析的多功能动态状态估计器 Article

Mehdi AHMADI JIRDEHI,Reza HEMMATI,Vahid ABBASI,Hedayat SABOORI

《信息与电子工程前沿(英文)》 2016年 第17卷 第11期   页码 1218-1227 doi: 10.1631/FITEE.1500301

摘要: 本文提出了一种基于卡尔曼滤波理论的动态状态估计新算法,可有效探测、识别并校正电力系统中的测试误差和支路参数误差。同时,该算法亦可成功探测和识别电力系统中的负荷突变。该方法在每段取样时间内,采用三种归一化向量对误差进行处理,包括归一化测量残差,归一化拉格朗日乘子,以及归一化新息向量。在IEEE14节点测试系统上对所提出的算法进行了可行性和效能验证,并通过对数值结果的呈示和讨论,说明了该方法的精确度。

关键词: 动态状态估计器;卡尔曼滤波;测试误差;支路参数误差;负荷突变    

Mean wind load induced incompatibility in nonlinear aeroelastic simulations of bridge spans

Zhitian ZHANG

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 605-617 doi: 10.1007/s11709-018-0499-x

摘要: Mean wind response induced incompatibility and nonlinearity in bridge aerodynamics is discussed, where the mean wind and aeroelastic loads are applied simultaneously in time domain. A kind of incompatibility is found during the simultaneous simulation of the mean wind and aeroelastic loads, which leads to incorrect mean wind structural responses. It is found that the mathematic expectations (or limiting characteristics) of the aeroelastic models are fundamental to this kind of incompatibility. In this paper, two aeroelastic models are presented and discussed, one of indicial-function-denoted (IF-denoted) and another of rational-function-denoted (RF-denoted). It is shown that, in cases of low wind speeds, the IF-denoted model reflects correctly the mean wind load properties, and results in correct mean structural responses; in contrast, the RF-denoted model leads to incorrect mean responses due to its nonphysical mean properties. At very high wind speeds, however, even the IF-denoted model can lead to significant deviation from the correct response due to steady aerodynamic nonlinearity. To solve the incompatibility at high wind speeds, a methodology of subtraction of pseudo-steady effects from the aeroelastic model is put forward in this work. Finally, with the method presented, aeroelastic nonlinearity resulted from the mean wind response is investigated at both moderate and high wind speeds.

关键词: bridge     aerodynamics     nonlinear     aeroelastic model     Pseudo-steady     mean wind loads    

风机捕集能量和降低负荷使用的先进控制方法

Yuan Yuan,Tang Jiong

《工程(英文)》 2017年 第3卷 第4期   页码 494-503 doi: 10.1016/J.ENG.2017.04.023

摘要:

本文报道了风机控制领域最近才出现的一些新方法的调查研究结果。最近数年里,在时变不确定的紊乱风场中优化能量捕集效率和降低各个部件负荷的多元控制方法已经被广泛地研究。我们将相关的研究工作分为三类:风机建模和风机动力学研究、风机的主动控制和风机的被动控制。关于风机动力学研究,我们讨论了物理模型的建立,并且给出了空气弹性变形的分析工具。关于主动控制,我们审查了节距控制、扭矩控制和偏航控制等策略,包括相关的理论建立以及针对不同目的的应用情况。我们的研究主要关注风机叶片节距控制,节距控制被认为是在维持能量捕获性能的同时降低负荷的关键要素。关于被动控制,我们研究了调谐质量阻尼器、智能转子和Microtabs等技术。另外我们也提出了未来的一些研究方向。

关键词: 风机     控制方法     能量优化     降低负荷    

Response in piled raft foundation of tall chimneys under along-wind load incorporating flexibility of

B. R. JAYALEKSHMI,S.V. JISHA,R. SHIVASHANKAR

《结构与土木工程前沿(英文)》 2015年 第9卷 第3期   页码 307-322 doi: 10.1007/s11709-015-0288-8

摘要: The present paper deals with the numerical analysis of tall reinforced concrete chimneys with piled raft foundation subjected to along-wind loads considering the flexibility of soil. The analysis was carried out using finite element method on the basis of direct method of soil-structure interaction (SSI). The linear elastic material behavior was assumed for chimney, piled raft and soil. Four different material properties of soil stratum were selected in order to study the effect of SSI. The chimney elevation and the thickness of raft of piled raft foundation were also varied for the parametric study. The chimneys were assumed to be located in terrain category 2 and subjected to a maximum wind speed of 50 m/s as per IS:875 (Part 3)-1987. The along-wind loads were computed according to IS:4998 (Part 1)-1992. The base moments of chimney evaluated from the SSI analysis were compared with those obtained as per IS:4998 (Part 1)-1992. The tangential and radial bending moments of raft of piled raft foundation were evaluated through SSI analysis and compared with those obtained from conventional analysis as per IS:11089-1984, assuming rigidity at the base of the raft foundation. The settlements of raft of piled raft foundation, deflection of pile and moments of the pile due to interaction with different soil stratum were also evaluated. From the analysis, considerable reduction in the base moment of chimney due to the effect of SSI is observed. Higher radial moments and lower tangential moments were obtained for lower elevation chimneys with piled raft resting on loose sand when compared with conventional analysis results. The effect of SSI in the response of the pile is more significant when the structure-foundation system interacts with loose sand.

关键词: finite element method     piled raft     tall chimney     soil-structure interaction     along-wind load    

Challenge of global climate change: Prospects for a new energy paradigm

Michael B. MCELROY

《环境科学与工程前沿(英文)》 2010年 第4卷 第1期   页码 2-11 doi: 10.1007/s11783-010-0005-8

摘要: Perspectives on the challenge posed by potential future climate change are presented including a discussion of prospects for carbon capture followed either by sequestration or reuse including opportunities for alternatives to the use of oil in the transportation sector. The potential for wind energy as an alternative to fossil fuel energy as a source of electricity is outlined including the related opportunities for cost effective curtailment of future growth in emissions of CO.

关键词: climate change     carbon capture     wind     ethanol     CO2     radiative forcing    

Collapse fragility assessment of steel roof framings with force limiting devices under transient wind

Linjia BAI, Yunfeng ZHANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 199-209 doi: 10.1007/s11709-012-0168-4

摘要: Steel structural frame is a popular structural form to cover large-span roof space and under high winds. Either part of the roof enclosure or the entire roof structure can be lifted off a building, particularly for low sloped roofs subject to wind-induced suction force. Collapse of roof could cause severe economic loss and poses safety risk to residents in the building. The buckling of members in a steel roof frame structure, which may lead to progressive collapse, may be dynamic in nature. This paper presents a fragility analysis of the collapse of steel roof frame structures under combined static and transient wind loading. Uncertainties associated with wind load change rate and member imperfections are taken into account in this study. A numerical example based on a Steel Joist Institute (SJI) K series joist was used to demonstrate the use of force limiting devices for collapse risk mitigation. For the presented fragility assessment of steel roof collapse, a Monte Carlo method combined with response surface approach was adopted, which greatly reduces the computation time and makes the Monte Carlo simulation feasible for probabilistic collapse analysis of steel roof frame structures.

关键词: collapse     dynamic response     fragility analysis     Monte Carlo simulation     wind load    

Load shedding scheme for an interconnected hydro-thermal hybrid system with SMES

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

《能源前沿(英文)》 2012年 第6卷 第3期   页码 227-236 doi: 10.1007/s11708-012-0198-6

摘要: The frequency of the power system varies based on the load pattern of the consumers. With continuous increase in the load, the frequency of the system keeps decreasing and may reach its minimum allowable limits. Further increase in the load will result in more frequency drop leading to the need of load shedding, if excess generation is not available to cater the need. This paper proposed a methodology in a hybrid thermal-hydro system for finding the required amount of load to be shed for setting the frequency of the system within its minimum allowable limits. The load shedding steps were obtained based on the rate of change of frequency with the increase in the load in both areas. The impact of superconducting magnetic energy storage (SMES) was obtained on load shedding scheme. The comparison of the results was presented on the two-area system.

关键词: critical load     frequency response     load shedding     multi-area system     rate of change of frequency     superconducting magnetic energy storage (SMES) device    

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿(英文)》 2012年 第6卷 第2期   页码 184-192 doi: 10.1007/s11708-012-0185-y

摘要: Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.

关键词: doubly fed induction generator (DFIG)     load frequency control     inertial control     wind energy conversion system (WECS)    

Load shedding scheme for the two-area system with linear quadratic regulator

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

《能源前沿(英文)》 2013年 第7卷 第1期   页码 90-102 doi: 10.1007/s11708-012-0224-8

摘要: The power system is prone to many emergency conditions which may lead to emergency state of operation with decay in the system frequency. The dramatic change in the frequency can result in cascaded failure of the system. In order to avoid power system collapse, load shedding (LS) schemes are adopted with the optimal amount of load shed. This paper proposed a methodology in a two-area thermal-thermal system for finding the required amount of load to be shed for setting the frequency of the system within minimum allowable limits. The LS steps have been obtained based on the rate of change of frequency with the increase in load in steps. A systematic study has been conducted for three scenarios: the scheme with a conventional integral controller; the scheme with a linear quadratic regulator (LQR); and the scheme with an LQR and superconducting magnetic energy storage devices (SMES). A comparison of the results has been presented on the two-area system.

关键词: critical load     frequency response     load shedding (LS)     multi-area system     rate of change of frequency     linear quadratic regulator (LQR)     superconducting magnetic energy storage devices (SMES)    

全球气候变化背景下灾害性天气变化及对海上风电的影响

葛珊珊,,张韧

《中国工程科学》 2010年 第12卷 第11期   页码 71-77

摘要:

全面研究了我国灾害性天气状况,并基于已有的研究成果分析了全球气候变化的特点、驱动因子以及变化趋势,进一步探讨了气候变化背景下我国极端天气的响应。随后分析了海上风电场建设的气象和水文影响因素与潜在风险,特别强调了海上风电场应注意的防台风问题。

关键词: 全球气候变化     灾害性天气     海上风电场    

Experimental study of wind loads on gable roofs of low-rise buildings with overhangs

Peng HUANG, Ling TAO, Ming GU, Yong QUAN

《结构与土木工程前沿(英文)》 2018年 第12卷 第3期   页码 300-317 doi: 10.1007/s11709-018-0449-7

摘要:

Gable roofs with overhangs (eaves) are the common constructions of low-rise buildings on the southeastern coast of China, and they were vulnerable to typhoons from experience. The wind pressure distributions on gable roofs of low-rise buildings are investigated by a series of wind tunnel tests which consist of 99 test cases with various roof pitches, height-depth ratios and width-depth ratios. The block pressure coefficients and worst negative (block) pressure coefficients on different roof regions of low-rise buildings are proposed for the main structure and building envelope, respectively. The effects of roof pitch, height-depth ratio, and width-depth ratio on the pressure coefficients of each region are analyzed in detail. In addition, the pressure coefficients on the roofs for the main structure and building envelope are fitted according to roof pitch, height-depth ratio and width-depth ratio of the low-rise building. Meanwhile, the rationality of the fitting formulas is verified by comparing the fitting results with the codes of different countries. Lastly, the block pressure coefficients and worst negative pressure coefficients are recommended to guide the design of low-rise buildings in typhoon area and act as references for the future’s modification of wind load codes.

关键词: low-rise building     gable roof     wind loads     wind tunnel test     block pressure coefficient     load code    

Reactive power compensation of an isolated hybrid power system with load interaction using ANFIS tuned

Nitin SAXENA,Ashwani KUMAR

《能源前沿(英文)》 2014年 第8卷 第2期   页码 261-268 doi: 10.1007/s11708-014-0298-6

摘要: This paper presents an adaptive neuro fuzzy interference system (ANFIS) based approach to tune the parameters of the static synchronous compensator (STATCOM) with frequent disturbances in load model and power input of a wind-diesel based isolated hybrid power system (IHPS). In literature, proportional integral (PI) based controller constants are optimized for voltage stability in hybrid systems due to the interaction of load disturbances and input power disturbances. These conventional controlling techniques use the integral square error (ISE) criterion with an open loop load model. An ANFIS tuned constants of a STATCOM controller for controlling the reactive power requirement to stabilize the voltage variation is proposed in the paper. Moreover, the interaction between the load and the isolated power system is developed in terms of closed loop load interaction with the system. Furthermore, a comparison of transient responses of IHPS is also presented when the system has only the STATCOM and the static compensation requirement of the induction generator is fulfilled by the fixed capacitor, dynamic compensation requirement, meanwhile, is fulfilled by STATCOM. The model is tested for a 1% step increase in reactive power load demand at = 0 s and then a sudden change of 3% from the 1% at = 0.01 s for a 1% step increase in power input at variable wind speed model.

关键词: isolated wind-diesel power system     adaptive neuro fuzzy interference system (ANFIS)     integral square error (ISE) criterion     load interaction    

Load frequency control in deregulated power system with wind integrated system using fuzzy controller

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿(英文)》 2013年 第7卷 第2期   页码 245-254 doi: 10.1007/s11708-012-0218-6

摘要: This paper presents the analysis of load frequency control (LFC) of a deregulated two-area hydro-thermal power system using fuzzy logic controller, with doubly fed induction generators (DFIGs) integrated into both the control areas. The deregulation of power sector has led to the formation of new companies for generation, transmission and distribution of power. The conventional two-area power system is modified to study the effects of the bilateral contracts of companies on the system dynamics. Deregulation creates highly competitive and distributed control environment, and the LFC becomes even more challenging when wind generators are also integrated into the system. The overall inertia of the system reduces, as the wind unit does not provide inertia and isolates from the grid during disturbances. The DFIGs integrated provide inertial support to the system through modified inertial control scheme, and arrests the initial fall in frequency after disturbance. The inertial control responds to frequency deviations, which takes out the kinetic energy of the wind turbine for improving the frequency response of the system. To enhance the participation of the doubly fed induction generator (DFIG) in the frequency control, optimal values of the speed control parameters of the DFIG-based wind turbine have been obtained using integral square error (ISE) technique. The dynamics of the system have been obtained for a small load perturbation, and for contract violation using fuzzy controller.

关键词: frequency regulation     fuzzy controller     de-regulated power system     doubly fed induction generator (DFIG)     bilateral contract    

标题 作者 时间 类型 操作

Analysis on running safety of train on the bridge considering sudden change of wind load caused by wind

Tian ZHANG, He XIA, Weiwei GUO

期刊论文

Distribution of background equivalent static wind load on high-rise buildings

Jianguo ZHANG , Ming GU ,

期刊论文

一种针对测试误差、参数误差和负荷突变故障分析的多功能动态状态估计器

Mehdi AHMADI JIRDEHI,Reza HEMMATI,Vahid ABBASI,Hedayat SABOORI

期刊论文

Mean wind load induced incompatibility in nonlinear aeroelastic simulations of bridge spans

Zhitian ZHANG

期刊论文

风机捕集能量和降低负荷使用的先进控制方法

Yuan Yuan,Tang Jiong

期刊论文

Response in piled raft foundation of tall chimneys under along-wind load incorporating flexibility of

B. R. JAYALEKSHMI,S.V. JISHA,R. SHIVASHANKAR

期刊论文

Challenge of global climate change: Prospects for a new energy paradigm

Michael B. MCELROY

期刊论文

Collapse fragility assessment of steel roof framings with force limiting devices under transient wind

Linjia BAI, Yunfeng ZHANG

期刊论文

Load shedding scheme for an interconnected hydro-thermal hybrid system with SMES

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

期刊论文

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文

Load shedding scheme for the two-area system with linear quadratic regulator

D. TYAGI, Ashwani KUMAR, Saurabh CHANANA

期刊论文

全球气候变化背景下灾害性天气变化及对海上风电的影响

葛珊珊,,张韧

期刊论文

Experimental study of wind loads on gable roofs of low-rise buildings with overhangs

Peng HUANG, Ling TAO, Ming GU, Yong QUAN

期刊论文

Reactive power compensation of an isolated hybrid power system with load interaction using ANFIS tuned

Nitin SAXENA,Ashwani KUMAR

期刊论文

Load frequency control in deregulated power system with wind integrated system using fuzzy controller

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文