Results 31 to 40 of about 15,529 (196)

有限面积下的独立接地系统防雷优化设计

open access: yesDianci bileiqi, 2023
针对科研生产厂区独立接地系统难以长期有效降阻的问题,基于有限元理论建立了建筑独立接地系统的雷击暂态接地模型,基于该模型探究了有限面积下建筑独立接地装置的防雷降阻优化方法。研究结果显示,对于有限面积下安装的独立接地系统,采用接地网加装接地模块以及双地网加装垂直接地极的方式均有良好的降阻效果。在考虑造价经济性的前提下,使用双地网配合垂直接地极、且垂直接地极间距为10 m~20 m时有更好的降阻效果。研究结果对有限面积下建筑物独立接地系统的设计与优化具有一定的参考意义。
古维富   +4 more
doaj  

Research and simulation of resonant earthed system Based on IPC [PDF]

open access: yes, 2008
我国中压配电网,绝大多数采用中性点不接地方式。这种接地方式最大的优点是:当发生单相接地时,三相线电压的对称性没有被破坏,所以用户用电不受影响,可维持一定长的时间。但是,当配电网达到一定规模,对地电容电流达到一定数值后,必须采取加装消弧线圈的措施来保证配电网的安全。 配电网中性点采用消弧线圈接地的方式,对于改善电网供电质量、提高供电可靠性和保证整个系统安全运行都有十分重要的意义。本文在此背景下,对谐振接地系统展开研究与仿真。首先介绍了中性点接地方式的发展过程,通过对谐振接地原理和单相接地故障的分析 ...
柯远青
core  

A more‐than‐human political ecology of Indonesian songbird trade

open access: yesConservation Biology, EarlyView.
Abstract Since its inception, conservation science has considered wildlife trade a problem. In focusing on conservation outcomes, conservationists almost completely ignore the welfare of traded animals and plants and the harms they endure. We developed a political ecology approach that incorporates the interconnectedness of people with animals and ...
Sicily Fiennes   +9 more
wiley   +1 more source

直流接地极附近架空光缆拉线的接触电势研究

open access: yesDianci bileiqi, 2020
直流系统单极大地运行时通过接地极注入大地的电流会造成系列负面影响,某直流工程系统调试期间测得临近接地极的一架空光缆线路拉线接触电势高达440 V,安全风险极高。首先分析了架空光缆系统的结构特点,发现架空光缆的吊线与接地拉线构成了一个长距离多点接地系统。对典型架空光缆系统拉线的接触电势进行了理论计算,发现拉线接触电势取决于吊线接地点间的电位差和拉线接地电阻。采用基于边界元法的仿真软件CDEGS研究了土壤、线路走廊、以及拉线参数等对接触电势的影响 ...
陈伟   +6 more
doaj  

Discussion on application of information fusion techniques in electric power system fault detection [PDF]

open access: yes, 2016
2002-2003 > Academic research: refereed > Publication in refereed journalVersion of ...
Chan, WL   +4 more
core  

Making Interview Multilingualism Visible: Transnational Chinese Language Teacher Identity Construction

open access: yesInternational Journal of Applied Linguistics, EarlyView.
ABSTRACT This study examines multilingual practices in research interviews, focusing on English lexical insertions in Chinese‐language research interviews with teachers of Chinese in Australian secondary schools, and treating these code‐switches as analytically meaningful rather than incidental.
Chengwen Yuan, Tianwei Zhang, Gary Bonar
wiley   +1 more source

The underappreciated roles of fog and dew on vegetation and biocrusts

open access: yesNew Phytologist, EarlyView.
Summary Fog and dew represent minor components of ecosystem water budgets in most ecosystems. However, fog and dew can play an essential role in ecosystem dynamics and are particularly important for water‐limited systems. In addition to serving as direct water inputs, fog and dew can influence microclimate and water redistribution, thereby promoting ...
Lixin Wang, Yue Li, Mengyun Sun, Na Qiao
wiley   +1 more source

发变电站接地系统的季节系数分析

open access: yesGaoya dianqi, 2003
季节因素将影响接地系统的安全性能。季节系数随冰冻季节形成的地表高阻层的电阻率及其厚度的增加而增加。在我国北方高寒冰冻地区接地系统的接地电阻季节系数可达3.0,接触电压和跨步电压季节系数可能达到10和5.4。在雨季形成的地表低胆层也有可能导致接触电压的升高。采用垂直接地极能减小接地系统的季节系数,起稳定接地系统安全性能的作用。
何金良   +4 more
doaj  

试析超高层建筑电气工程防雷接地的对策

open access: yes, 2022
常规的防雷电接地系统设计中,由于其避雷区较窄不能适应高层建筑物的雷击要求,所以进行了关于该技术的探讨。在此基础上,采用了防雷接地网和地基接地网的排布,电气工程的避雷接闪装置的选用,从而达到防雷的目的。经比较试验,表明此方案能较好地拓宽电网的防雷区保证电网的正常运营。
王 麒锦
core   +1 more source

Navigating the Algorithmic State: Public Values and Citizens' Preferences of AI‐Driven Public Service Delivery

open access: yesPublic Administration, EarlyView.
ABSTRACT As the public sector increasingly adopts AI‐powered automated decision systems (ADS), understanding how citizens experience and value ADS use in public decision‐making is both normatively and practically important. Therefore, we examine and compare the effects of seven attributes of public values on citizens' support for ADS adoption in two ...
Guimin Zheng   +4 more
wiley   +1 more source

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