Results 81 to 90 of about 7,424,509 (170)
Gaoya dianqi, 2015 影响快速暂态过电压（very fast transient overvoltage,VFTO）因素很多,其中气体变电站（GIS）设备模型的选择对VFTO计算结果精确度的影响不可忽略。笔者采用考虑弧道电感特性的电弧电阻模型,结合国外某1 000 k V GIS变电站,详细计算了GIS内部的VFTO,分析了GIS内部关键设备处VFTO的极值。结果表明,用考虑弧道电感特性的电弧电阻模型模拟隔离开关的电弧的物理过程,进而对VFTO研究是适用的。最后还研究了入口电容、静态电感、GIS支路长度对VFTO的影响。
刘德东 +3 more
doaj
Experimental characterization and modelling of a cavitating centrifugal pump operating in fast start-up conditions [PDF]
, 2010 The start-up of rocket engine turbopumps is generally performed only in a few seconds. It implies that these pumps reach their nominal operating conditions after only a few rotations.
Bois, Gérard +4 more
core
Gaoya dianqi, 2016 文中采用电磁暂态分析程序（electro-magnetic transients program,EMTP）,以西山750 kV气体绝缘开关设备（gas insulated switchgear,GIS）电站为工程背景,计算研究了多种运行方式下隔离开关操作引发的快速暂态过电压（very fast transient overvoltage,VFTO）,深入分析了VFTO波形的特点,提取出其特征参量,并对特征参量进行规律统计,为VFTO标准波的归纳提供参考。计算结果表明,西山750 kV ...
朱跃, 周越, 颜湘莲, 王浩
doaj
With the large-scale integration of renewable energy devices into the power grid, the voltage stability of the renewable energy base is becoming increasingly weak, and the problem of transient overvoltage is becoming increasingly severe.
Xindi Liu, Jiawen Cao, Changgang Li
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FAST FREQUENCY MODEL OF OVERVOLTAGE IN ADJUSTABLE SPEED DRIVES: SiC TECHNOLOGY VS. IGBT TECHNOLOGY
, 2018 International audienceThe use of fast semiconductor components such as IGBT and SiC in Adjustable Speed Drives (ASD) increases power density and provides better controllability.
Belinger, Antoine +4 more
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As a predominant issue within line-commutated converters-based high voltage direct current (DC) transmission systems, commutation failure may trigger transient overvoltage problems and the tripping of large-scale renewable generation sets in hybrid AC/DC
Tao Ding +4 more
core +1 more source
Gaoya dianqi, 2017 在特快速瞬态过电压（very fast transient overvoltage,VFTO）的研究进程中,隔离开关操作过程中电弧重燃与熄弧的等效模型的建立,对VFTO计算结果有着重要的影响。采用ATP-EMTP内建MODELS模块,结合Mayr电弧分析理论,并考虑电弧电流过零熄弧的影响,建立了一种动态电弧模型。将该模型应用于某500 kV GIS电站VFTO计算中,并与另两种模型进行比较,详细分析其特性,结果表明,与简单电弧模型相比,动态电弧模型考虑了弧道电阻动态变化过程,使得VFTO最大幅值减小 ...
刘文博 +5 more
doaj
Analysis of Transient Overvoltages within a 345kV Korean Thermal Plant
, 2012 -This paper presents the simulation results for the analysis of a lightning surge, switching transients and very fast transients within a thermal plant. The modeling of gas insulated substations (GIS) makes use of electrical equivalent circuits that are ...
Chul-Hwan Kim, Sang-Min Yeo
core
Gaoya dianqi, 2013 全封闭SF6气体绝缘组合电器（gas insulated switchgear,GIS）中隔离开关操作产生的特快速暂态过电压（very fast transient overvoltage,VFTO）会严重影响电力系统的稳定性及相关设备的安全运行。通过研究GIS隔离开关的击穿过程和电弧的发展变化过程,进而采用合理的电弧模型进行仿真计算,对于得到较为准确的VFTO波形有重要意义。笔者对当前VFTO仿真中GIS隔离开关的传统电弧模型、改进模型及电弧特性的试验研究等进行了详细的介绍 ...
刘教民 +4 more
doaj
Generation mechanism and influencing factors of transient overvoltage on ultra high-voltage direct current transmission [PDF]
The transient overvoltage caused by faults in ultra-high-voltage direct current (UHVDC) transmission lines and alternating current (AC) systems can adversely affect system safety and stability.
Weiwei Yao +6 more
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