Results 21 to 30 of about 954,672 (163)

谐波电流下油浸式配电变压器负载损耗及绕组热点温度分析

open access: yesGaoya dianqi, 2018
为了研究电流畸变情况下油浸式配电变压器负载损耗和绕组热点温度的变化规律,基于IEEE StdC57.110中的绕组涡流谐波损耗因子和杂散谐波损耗因子,并考虑绕组在谐波电流下的集肤效应会增强,定义了绕组电阻谐波损耗因子,从而建立了变压器在谐波电流下负载损耗计算模型。考虑到绕组涡流损耗密度分布不均对绕组热点温度的影响,利用文中所建立的变压器在谐波电流下负载损耗计算模型修正了IEEE Std C57.110:2008的绕组热点温度计算公式。分析结果表明,谐波电流会引起较大的额外负载损耗,谐波畸变率为40 ...
周卫华   +7 more
doaj  

油浸式变压器热点温升计算中绕组结构简化的误差分析

open access: yesGaoya dianqi, 2021
变压器温度流体场三维仿真是准确计算变压器绕组热点温度的重要方法,然而变压器绕组结构复杂,精确三维建模和网格剖分困难,计算效率低,难以满足实际工程需求。文中针对变压器温度流体场计算过程中绕组结构类型以及撑条、垫块、外包绝缘纸对绕组热点温度的影响进行了讨论,在一定的容许偏差内对绕组结构进行简化分析,得到以下结论:网格控制方法及剖分精度对计算结果有较大影响,采用扫描剖分方法能够在绕组附近区域获得高质量的六面体网格,具有较高剖分效率;对温度、流速等变化较快的区域进行局部加密 ...
晋涛   +7 more
doaj  

A Stretchable Sandwich Composite Film With Ultra‐Broadband Electromagnetic Interference Shielding and High‐Performance Photothermal Conversion Capability

open access: yesRare Metals, Volume 45, Issue 3, March 2026.
ABSTRACT With the rapid growth demand for advanced integrated electronic systems, lightweight flexible electromagnetic interference (EMI) shielding films integrated with functional properties, such as excellent mechanical properties and self‐healing capability, are a research focus in high‐tech functional materials. Herein, a sandwich‐structured aramid
Dan Guo   +9 more
wiley   +1 more source

基于主热流分析的三芯电缆接头热点温度反演辨识方法及试验验证

open access: yesGaoya dianqi
电力电缆由电缆本体和电缆接头组成,电缆接头内部的温升是影响电力电缆线路载流能力的关键因素。针对电缆接头材料参数分散性大和热流扩散规律不明显等问题,文中提出了一种基于主热流分析的电缆接头热点温度反演辨识方法,以准确辨识接头内部的热点温度。首先建立了10 kV三芯电缆及接头的有限元仿真计算模型,得到温度场分布规律。其次通过分析电缆接头的热流扩散规律,建立了电缆本体的热路模型,并采用正交试验法设计训练样本和测试样本,确定了距离接头端部0.1、2.0 m的2个导体特征温度点 ...
侯澳港   +5 more
doaj   +2 more sources

油浸式变压器热路模型的修正及实验验证

open access: yesGaoya dianqi, 2019
变压器绕组的热点温度是限制运行中变压器负载能力和影响变压器寿命的最大因素。快速准确地获取变压器绕组热点温度对变压器安全稳定运行具有重要意义。文中根据变压器不同的冷却方式,对变压器片式散热器的散热热阻进行了修正。并通过变压器温升实测数据与模型仿真计算数据的比较,验证了修正散热热阻后热路模型的有效性和准确性,从而得到了一个快速且较为准确的计算变压器热点温度的方法。
罗汉武   +7 more
doaj  

Ru‐Ag Dual Atom Sites for Methane Detection Enabling Intelligent Thermal Runaway Warning in Lithium‐Ion Batteries

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT Early detection of thermal runaway (TR) is essential for lithium‐ion battery (LIB) safety, as unchecked TR risks catastrophic failures in energy storage systems. Gas‐based sensing offers a faster and more direct approach by detecting decomposition products at the molecular level.
Tianshui Liang   +9 more
wiley   +1 more source

基于DGM的油浸式变压器热点温度计算

open access: yesGaoya dianqi, 2015
为了准确计算油浸式变压器的热点温度,在对比了有限元法(FEM)和有限体积法(FVM)计算变压器热点温度各自特点的基础上,提出了基于间断式伽辽金方法(discontinuous Galerkin method,DGM)的一种计算变压器热点温度的全新计算方法;并以天威合肥变压器厂的一台180 MV·A-220 kV变压器为例,计算了变压器的绕组热点温度。为校验计算方法的准确性,笔者对这台主变进行了变压器绕组温升试验,监测了绕组的热点温度数据,并将利用DGM的计算结果分别与实际监测数据、IEEE导则计算数据 ...
律方成   +5 more
doaj  

Multifunctionality of Magnetic La(Fe, Si/Al)13‐Based Materials: Negative Thermal Expansion and Magnetocaloric Effect

open access: yesRare Metals, Volume 45, Issue 2, February 2026.
ABSTRACT In recent years, the field of magnetic materials has witnessed a paradigm shift from single‐function applications to multifunctional integration, driven by the growing demand for smart materials in advanced technologies. Among various magnetic systems, La(Fe, Si/Al)13‐series materials have emerged as particularly promising candidates due to ...
Irfan Liaquat   +2 more
wiley   +1 more source

The Effects of Working Memory Updating on Chinese Reading Comprehension Among Bilingual Primary School Students

open access: yesNew Directions for Child and Adolescent Development, Volume 2026, Issue 1, 2026.
Background Working memory updating is crucial in bilingual children′s second language (L2) reading comprehension. A robust updating ability is a cognitive key for children to successfully master L2 reading comprehension. Objective This study is aimed at investigating the effect of updating ability on the L2 Chinese reading comprehension among Uyghur ...
Guangxin Li   +3 more
wiley   +1 more source

35kV油浸式变压器绕组热点温度计算分析

open access: yesGaoya dianqi, 2017
为提高变压器的热模型准确性,在35 kV变压器绕组上布置了基于光纤光栅(fiber bragg grating,FBG)温度传感器的测温系统,实时、精确地获取变压器内部的热点温度,充分掌握了变压器绕组温度的分布情况。通过与传统热模型计算结果进行的对比分析,结果表明:绕组热点出现在距顶端1/4处,且理论计算值平均高于测量结果3.29℃。为准确获取变压器绕组热点温度和热路模型,建议将光纤测温技术推广应用至高电压等级变压器上,以实测数据构建变压器绝缘性能及暂态过载能力的评判依据 ...
李鑫   +5 more
doaj  

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