Results 41 to 50 of about 12,978 (169)
Gaoya dianqi, 2018 近些年随着电网中直流时间常数的增大,导致短路电流中直流分量衰减速度很慢,超出高压交流断路器在设定时间内开断短路故障的能力。因此,直流时间常数的计算与评估对电网的优化设计和安全运行尤为重要。文中通过构造函数提出了积分法、差分法、组合法3种计算短路电流中直流分量特征参数（初始值I0和时间常数τ）的方法,并应用积分法、差分法、组合法分别对含有三次、五次谐波的3种典型的短路电流波形进行直流分量特征参数计算。研究结果表明:积分法、差分法、组合法对理想的短路电流波形均能够零误差的计算直流分量的初始值和时间常数 ...
王蒙 +4 more
doaj
Fault Characteristic Study Based on FLUX 2D for Large Synchronous Generators With Stator Winding Inter-turn Short Circuits Under Rated Operating Conditions [PDF]
, 2013 该文采用单一绕组分析和有限元分析相结合的方法,研究大型同步发电机在额定运行方式下定子绕组匝间短路故障特性。该方法同样适用于确定故障条件下的电流和转矩。对于内部故障情况的电磁瞬态仿真必须考虑到一些特殊措施,如单一绕组和电网之间正确的连接对于模拟内部故障是相当关键的。以往的结果表明,在内部磁场非对称的情况下,基于等效电路的经典算法是不适用的。该文通过对汽轮发电机匝间短路故障进行系统的研究,表明:其短路电流、相电流、转矩和径向力与短路的位置及匝数紧密相关。在一些短路情况下,发电机将产生很大的局部电流 ...
J.Rosendahl +3 more
core
Clip Voice: Misogyny and the Renegotiation of a Gendered Vocal Style in Chinese Digital Discourse
Journal of Sociolinguistics, Volume 29, Issue 5, Page 348-359, November 2025.ABSTRACT The participatory culture of social media allows women's voices to be heard but also parodied and policed. On Chinese social media platforms, where performers rapidly adopt and transform vocal trends for engagement, discourse on gendered vocal styles has proliferated.
Zichuan Yu, Rebecca Lurie Starr
wiley +1 more source
Gaoya dianqi, 2008 笔者介绍了用于高压直流电流测量的电子式直流电流互感器,针对其中决定测量结果的关键部分-分流器及一次联结导体,重点进行了热效应分析。理论分析得出:分流器自身和一次联结导体在直流大电流下都有热效应,而在高压直流线上谐波和阶跃响应产生的集肤效应还将导致不可忽视的附加热效应;一次联结导体的交、直流热效应共同作用将对分流器的测量产生影响。实验证明鼠笼结构的分流器可有效地抑制谐波电流的热效应,电子式直流电流互感器的热稳定性试验不宜用工频交流等效,只有采用实际直流才能真实可靠的反映其热稳定性能。
徐雁 +6 more
doaj
短路电流直流分量对断路器电弧长度、压气室压力、喷口气体质量流的影响研究
Gaoya dianqi, 2021 随着电网容量的不断增大,电力系统短路电流直流分量的时间常数有很大可能大于其标准时间常数45 ms。目前非对称短路电流直流分量对断路器燃弧阶段关键参数的影响规律尚无研究。因此,文中研究目标是获得短路电流直流分量对断路器燃弧阶段关键参数的影响规律。基于高压断路器内部结构建立电弧物理焓流仿真模型,分别研究气体断路器开断对称电流和非对称电流时,燃弧阶段的关键电弧参数如电弧长度、压气室压力、喷口处气体质量流等参数的变化规律。研究结果显示:相同燃弧时间条件下,相比于对称短路电流,非对称短路电流开断时 ...
马飞越 +7 more
doaj
Integrative Conservation, Volume 4, Issue 3, Page 277-286, September 2025.This study provides an innovation to address the challenge in accessibility to samples and genetic markers in Snow leopard conservation genetic studies. We performed next‐generation sequencing (NGS) on 19 fecal samples obtained from the eastern Qinghai‐Tibet Plateau, and successfully assembled 17 complete mitogenome sequences (~16,720 bp) and ...
Chen Cheng +7 more
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Gaoya dianqi, 2022 为了研究集群电缆敷设方式、回路间距、回路数以及排列方式对交流集群电缆直流载流量的影响，以10 kV交流配电网中广泛使用的三芯交联聚乙烯（XLPE）电缆为例，通过有限元仿真软件建立集群电缆的温度场和流场耦合仿真模型，得到了直埋敷设、排管敷设和沟槽敷设下集群电缆以双极式直流拓扑结构运行时的直流载流量、温度分布和流场分布。结果表明：随着回路间距和回路数的增大，集群电缆载流量的变化速率逐渐减小。直埋敷设下集群电缆之间的热场相互作用最大，而沟槽敷设下集群电缆之间的热场相互作用最小 ...
王启隆 +3 more
doaj
New mechanism of cable anti-theft based on impedance discontinuity measurement methods [PDF]
, 2012 为了解决目前低压电力电缆防盗机制的局限性和缺陷,分析对比了目前各种电缆防盗技术的原理及优点,提出了加载直流电压法和采用交流采样的阻抗测量算法相结合的一种新型综合电缆防盗机制。该机制采用模糊逻辑判断阻抗及电流的特性,根据微机电缆保护的整定值,通过对盗割电缆时电流动态分析,快速给出可靠的报警信号。This paper analyzes the principles and advantages of current cable guard alarm technologies.The limitations
余臻
core
Intrapulse modulation recognition of signals based on statistical test of energy focusing efficiency [PDF]
, 2013 A blind intrapulse modulation recognition based on energy focusing efficiency test was proposed, which can be used to estimate the modulation type under low signal to noise ratio (SNR) conditions.
Guo-bing HU +4 more
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Integrative Conservation, Volume 4, Issue 3, Page 302-309, September 2025.We discussed the key assumptions of Distance sampling that were considered hard to meet in mountainous terrains and potential solutions for them. Our survey yielded comparable estimates from distance sampling and double‐observer survey, although the confidence interval from distance sampling was broader.
Lingyun Xiao +4 more
wiley +1 more source