Results 41 to 50 of about 6,941 (128)
Gaoya dianqi, 2015 由于气体绝缘变电站（GIS）隔离开关操作而产生的快速暂态过电压（very fast transient overvoltage,VFTO）,具有高频率、上升时间短、高幅值等特点,对GIS本体及相邻设备有较大危害。文中在隔离开关测量系统的基础上,研究了变压器耦合电容和隔离开关分合闸速度对VFTO和快速暂态电流（very fast transient current,VFTC）的影响。当变压器耦合电容分别取300、800、1 100 p F时,试验结果得出VFTO和VFTC的幅值会随着耦合电容的升高而增大 ...
赵承楠 +4 more
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Digest of Middle East Studies, Volume 34, Issue 3, Summer 2025.ABSTRACT The Arab Spring resulted in an expansion of social and individual freedoms in Tunisian society, but it also brought political instability, negatively impacting what had long been the country's primary source of employment—tourism. This economic crisis forced many to improvise their own sources of income, and it was in this context that a new ...
Camila Ponce Lara
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Effect of uneven tolerance to human disturbance on dominance interactions of top predators
Conservation Biology, Volume 39, Issue 2, April 2025.Abstract Anthropogenic activities may alter felid assemblage structure, facilitating the persistence of tolerant species (commonly mesopredators), excluding ecologically demanding ones (top predators) and, consequently, changing coexistence rules. We aimed to determine how human activities influence intraguild relationships among top predators and ...
Pablo Villalva +2 more
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Gaoya dianqi, 2017 为了解决目前因内部电弧故障影响整套开关柜退出运行的状况,提高供电可靠性,文中设计了一种开关柜内部电弧故障的保护方法。它是利用超快速接地开关快速接地来转移开关柜内部故障电弧电流,同时利用超快速接地开关在300 ms内完成合闸和分闸操作,熄灭电弧并减轻因电弧对柜内绝缘和元件的损坏,这样可以让开关柜母线上的断路器完成重合闸操作,恢复供电。这种设计可以在不改变现有断路器标准操作循环的基础上,极大地提高供电可靠性。
王自立, 李六零
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Essential skills for the training of conservation social scientists
Conservation Biology, Volume 39, Issue 2, April 2025.Abstract Since 2000, the field of biodiversity conservation has been reckoning with the historical lack of effective engagement with the social sciences in parallel with rapid declines in biodiversity and escalating concerns regarding socioecological justice exacerbated by many common conservation practices.
Laura Thomas‐Walters +9 more
wiley +1 more source
Challenges in assessing the effects of environmental governance systems on conservation outcomes
Conservation Biology, Volume 39, Issue 1, February 2025.Abstract Effective governance is crucial for the success of conservation projects aimed at protecting wildlife populations and supporting human well‐being. However, few large‐scale, comprehensive syntheses have been conducted on the effects of different environmental governance types on conservation outcomes (i.e., biological and ecological ...
Raphael A. Ayambire +17 more
wiley +1 more source
Gaoya dianqi, 2017 基于永磁斥力机构的真空快速开关因结构简单、动作迅速、可靠性高、容易实现电子控制和开关智能化等优点,引起了国内外学者的重视和研究。为了进一步提高永磁斥力机构的运动速度,为真空快速开关提供技术支持,文中采用有限元方法对影响永磁斥力机构的因素进行了研究。在用Maxwell建立永磁斥力机构的简化模型后,计算了基于永磁斥力机构的真空快速开关的动作特性,并采用单一变量法研究了包括运动部分质量、金属盘尺寸及直流、外接电路参数对机构运动的影响,并根据计算结果制作了12 kV样机。仿真结果表明,减少运动部分质量 ...
艾绍贵 +6 more
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Gaoya dianqi, 2011 超高压GIS内开关操作引起的快速暂态过电压严重威胁了电力系统运行的安全性。笔者针对某550 kVGIS,建立了仿真模型并确定了相关参数,研究了多种运行方式、隔离开关不同操作条件下GIS内部各节点的快速暂态过电压,得到了操作顺序对过电压的影响规律,同时分析了隔离开关并联电阻对快速暂态过电压的抑制作用。结果表明,隔离开关分闸操作产生的过电压幅值远大于其合闸操作产生的过电压;切换母线操作产生的过电压较严重;被操作开关处的VFTO受操作方式影响最大;隔离开关并联电阻加速了过电压的衰减抑制效果明显 ...
刘青
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Gaoya dianqi, 2022 针对直流电网对快速真空开关分闸要求高的问题，提出了一种基于电磁斥力—永磁保持式机构的快速真空开关。利用有限元方法对永磁保持机构保持力和电磁斥力—永磁保持式机构分闸动作过程多物理场进行仿真分析，得出了永磁体厚度和静铁心内部厚度对永磁保持机构保持力的影响，掌握了变化量对机构分闸动作过程的影响。通过对基于电磁斥力—永磁保持式机构的快速真空开关样机的分闸特性测试，与仿真结果具有高度一致性，证明其正确性，对后续此类机构的优化设计具有指导意义。
张公一 +6 more
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Gaoya dianqi, 2017 随着配电网中越来越多的使用固体绝缘的电缆线路,传统中性点经消弧线圈接地的灭弧措施暴露出诸多问题,已不能满足电网安全稳定运行的要求。文中研究了一种快速开关型消除弧光接地故障（简称消弧）技术,介绍了该技术相对于传统消弧线圈的优点,对其消弧原理以及相应的故障判别、故障选相、故障选线等环节进行研究,提出了快速开关型消弧装置的动作流程,并通过仿真分析验证了快速开关型消弧技术原理的可行性和动作流程的合理性。结果说明快速开关型消弧技术在理论上可以达到快速消除电弧接地故障的目的,有助于提高配电系统的供电可靠性。
艾绍贵 +5 more
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