Results 41 to 50 of about 14,233 (144)
The Application of Residual Current Protection Device in The Electrical Fire Prevention [PDF]
, 2014 剩余电流动作保护装置是防范电气火灾的有效方法之一。本文结合规范要求及系统原理对剩余电流动作保护装置在防范火灾中的应用做了几点阐述和总结。The residual current protection device is one of the effective methods to prevent electrical fires.This paper introduces some points and summarizes the application of residual current ...
张晓山
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, 2020 从本质上介绍了不接地系统到电阻或消弧线圈接地系统的演变过程；引出了接地变和接地变兼站用变的概念，解释了接地变、接地变兼站用变的构造和原理；遵照国家标准，并借鉴项目经验，总结了通过接地变兼站用变铭牌参数确定短路阻抗选取基准侧的方法，并且结合实例给出了详细的解释推导，奠定了接地变兼站用变的短路电流计算，继电保护整定计算的计算基础；基于确定基准侧后的短路电流计算，分析了接地变兼站用变与普通接地变的速断保护整定计算的差异，分别从躲过变压器低压侧出口三相短路 ...
志磊 辛
core +1 more source
Ultrasound in Obstetrics &Gynecology, Volume 64, Issue 4, Page 470-479, October 2024.ABSTRACT Objectives Our aim was to examine the prenatal profiles of pregnancies affected by an atypical chromosomal aberration, focusing on pathogenic copy‐number variants (pCNVs). We also wanted to quantify the performance of combined first‐trimester screening (cFTS) and a second‐trimester anomaly scan in detecting these aberrations. Finally, we aimed
K. Gadsbøll +6 more
wiley +1 more source
Analysis on the Current Phase Compensation in Differential Protection for Transformer [PDF]
, 2013 分析了接线双绕组变压器微机差动保护相位补偿采用角接与算法相位补偿关系,变压器差动保护内部两相短路故障灵敏度与相位补偿关系,得出无论变压器中性点是否接地,相位补偿选择低压侧的方案对差动保护灵敏度有利。This paper analyzes the relationship between angle-connection phase compensation and the algorithm phase compensation using in the current phase ...
朱文强, 谢珍贵, 黄兴平
core
An integrated historical study on human–tiger interactions in China 中国人虎互动关系的综合性历史研究
Integrative Conservation, Volume 3, Issue 3, Page 183-195, September 2024.Tigers are important for maintaining a variety of life in the world as they are the top predators in the food chain. Human–wildlife conflict, including conflicts between humans and tigers, has been a global issue throughout history. This article focuses on human–tiger interactions in China, discussing various types of conflicts and measures for ...
Zhihong Cao +4 more
wiley +1 more source
Gaoya dianqi, 1992 【问】什么是异相接地故障?电力部门为什么要求在非有效接地系统中应选用通过异相接地故障开断试验的断路器? 【答】在中性点非有效接地系统中,在一相断路器的内侧和另一相断路器的外侧各产生一个单相接地的故障,称为异相接地故障。异相接地故障实际是一种特定的两相接地故障。在开断异相接地时,断路器首开相上将出现1.73倍相电压工频过电压 ...
林立生
doaj
Dianci bileiqi, 2023 我国城市中低压配电网电容电流急剧上升且消弧线圈补偿效果欠佳，单相接地故障电弧难以自熄易产生弧光接地过电压及扩大事故，探究弧光接地故障的快速有效熄弧方法是保障配网稳定安全运行的基础。首先根据主动转移型消弧技术的工作原理，建立熄弧过程的等效电路，利用叠加定理推导熄弧时故障点电流计算公式，分析其与故障点位置、接地点过渡电阻、线路负荷电流等因素的关系；然后采用Matlab/Simulink搭建10 kV小电流接地系统单相接地故障模型，其中采用控制论电弧模型模拟单相弧光接地故障；最后通过设置典型的故障点位置 ...
李景丽, 任俊跃, 赵子敬
doaj
Topical and transdermal botanical formulations of the Chinese pharmacopoeia—A review
Phytotherapy Research, Volume 38, Issue 9, Page 4716-4735, September 2024.Abstract In pharmaceutics, ingredients are classified as active ingredients and excipients. In topical/transdermal phytomedicines, an ingredient may serve both functions. Published information on these dual‐purpose ingredients and their pharmacological relevance is limited.
Jingyi Gu +3 more
wiley +1 more source
Research and Implementation on New Embedded Extra High Voltage Distance Protection System [PDF]
, 2009 近年来，随着我国国民经济的快速发展，国家加大了电力基础设施的建设，输电网络也越来越复杂，国家对电力系统的安全运行提出了更高的要求，而传统的嵌入式微机保护装置，由于其在硬件平台设计和软件原理、算法的局限性，越来越不适应电力系统日益复杂的网络构架和运行方式，不能准确识别系统故障或运行异常等情况，保护误动、拒动时有发生，给国民经济造成了重大损失，所以，开发新一代的微机保护已经成为电力系统专业的科研院所、生产厂家近几年研发方向的重点。 本课题研究的目的正是力求开发一种新型的嵌入式微机保护 ...
赵长兵
core
Ultrasound in Obstetrics &Gynecology, Volume 64, Issue 1, Page 71-78, July 2024.ABSTRACT Objective To validate externally the QUiPP App v.2 algorithms in an independent cohort of high‐risk asymptomatic women attending a preterm birth (PTB) surveillance clinic in Ireland. Methods This was a retrospective, single‐center, observational study assessing discrimination and calibration of the QUiPP App v.2 at six predetermined clinical ...
L. Creswell +4 more
wiley +1 more source