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电流互感器励磁特性是计量和保护的重要参数,前者涉及电能计量和损耗测试,后者关乎保护装置的灵敏度和电力系统可靠运行.针对CT的常规测试要求,采用对励磁特性的相关测试方法,推出基于等效磁通原理的直流测试,该方法可以省去传统方法的升流升压设备,大幅度有效降低测试电压和设备体积,不仅适用于励磁特性曲线测试,还适用于精确励磁线性参数测试并用于计量误差计算. 相似文献
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《中国测试》2017,(10):97-101
为研究配电网中非线性单相负载混合谐波源的特性,提出单相混合谐波源重要参量的分析方法及计算方法。通过分析单相混合谐波源的电压电流特征,给出包含谐波、间谐波、次谐波成分的混合谐波源电压电流瞬时值、有效值的分解方法和计算方法。依据基础公式推导,提出电压电流总谐波失真的计算方法,提出混合谐波源瞬时功率、有功功率的分解方法和计算方法,得出总有功功率测量理论误差与时间的关系。利用该文提出的系列算法,对配电网中某一非线性负载谐波源测试数据进行仿真分析,结果表明:该系列算法能有效计算电压、电流总谐波失真偏差,能准确表征总有功功率测量理论误差与时间的关系,测量时间越大,由间谐波引起的误差越不显著。 相似文献
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为了实现较高的励磁频率,提高响应速度,同时减少电磁流量计的功耗,提出基于电压电流比值的瞬态测量方法,确定电压电流比值与流量之间的关系。设计了基于DSP的硬件,采集瞬态时的励磁电流和信号电压来验证该处理方法,离线数据分析表明,电压电流比值与流量有良好的线性关系。设计的DSP软件可实时实现瞬态测量方法,并进行水流量标定和功耗测试实验。实验结果表明,流量测量准确度达到0.5级,与普通电磁流量计相同。功耗对比表明,基于瞬态测量原理的电磁流量计的励磁功耗是普通电磁流量计的30%。 相似文献
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本文讨论了脉冲调宽乘法器用于交流测量时交直流变换误差与时分割频率的关系,提出了一咱新的准确计算方法,并对相移误差等因素作了分析,给出了减小误差的措施。最后介绍了基于上述分析而设计研制的标准功率,电压、电流测量仪,其测量功率,电压、电流的镧上于0.01%。 相似文献
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笔者在检测工作中,常遇到非正弦周期电压值测量的问题。在无示波器,只用万用表进行测量的情况下,是无法得到被测量正确的电压有效值的。为此,笔者通过间接的方法,即先从表盘读数算出平均值.再根据被测电压的波形因数Kf和波峰因数Kp计算出有效值和峰值。因此,只要测出电压平均值,问题即基本解决。 相似文献
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本文对基于数字采样技术的真有效值变换器数字多用表在测量低频交流电压时的误差进行了分析 ,并给出了理论计算值及实际测量结果。 相似文献
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本文介绍了一种采用“最急下降法”原理的交流电压、电流真有效值变送器,适用于各种非正弦波和畸变波之电压、电流值的测试。 相似文献
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介绍我们自行研制的一种基于PSoC的宽量程电能计量模块——EPSOC。利用PSoC特有的自调量程技术,能使电压量程宽达46~460V,电流量程宽达0.5-120A。EPSoC可以测量电压有效值、电流有效值、有功功率、无功功率等电力参数,它可以用于单(三)相电能表、电量变送器,也可以用于电力监测装置。 相似文献
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Mating magnetic reeds produces an electrical potential upon excitation. These potentials arise from two causes and have two distinct waveforms. The observation results of the polarities of the potentials are described. 相似文献
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Flexural traveling wave excitation based on shear-shear mode 总被引:1,自引:0,他引:1
Shuxian Dong Jindong Zhang Hyeoung Woo Kim Strauss M.T. Uchino K. Viehland D. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(10):1240-1246
This paper presents a new mechanism for circular flexture traveling wave excitation, which is based on a shear-shear mode in a single piezoelectric disc with a center hole was poled along its radial direction. Its bottom electrode was divided into four parts, and the top electrode acted as common ground. By use of a pair of alternating current (AC) voltage signals (sine and cosine), at the disc's resonance frequency, a flexural traveling wave was generated circumferentially. Both finite element modeling (FEM) analysis of transducers by integration of Laplace equations (ATILA) analysis and experimental results demonstrate the concept. As an application example, a shear-shear mode prototype was constructed and characterized. 相似文献
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主要研究了一种新的电磁超声激发方法.脉冲电磁超声的激发,旨在提高电磁超声换能器的磁声转换效率,解决其灵敏度低以及热效应的不良影响等问题。设计制作了脉冲电磁超声的激发装置。通过实验验证,该方式超声信号强度较强,激发装置发热量小。最后分析了超声波信号的激发强度与初始电压、电容容值等因素的关系,认为线圈中铁芯的加入在一定程度上可以提高磁声转换的效率。但目前产生的超声波信号频率仍在低频范围内,在今后的研究中还将进一步考虑采用信号压缩等方法来提高频率。 相似文献
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在多点激励动力分析中,传统的虚拟激励法将绝对位移分解成拟静力位移和动态相对位移两部分,而且在构造虚拟加速度及位移激励进行求解时须计算结构拟静模态矩阵,所以必须编制专用程序用于求解,这在一定程度上限制了虚拟激励法的应用。本文提出了一种绝对位移直接求解的虚拟激励方法,该方法通过在支座附加一大质量块并对大质量块构造虚拟力激励从而实现对绝对位移直接求解。该方法不需要另外计算拟静模态矩阵,所以新虚拟激励法可应用于任何具有简谐振动分析模块的有限元软件如ANSYS等,这为虚拟激励法工程应用开拓了广泛的前景。 相似文献
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V. G. Nevolin 《Journal of Engineering Physics and Thermophysics》1984,46(3):303-306
It is demonstrated that the thermocapillarity effect can either raise or lower the threshold of surface wave excitation, depending on the conditions of heating.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 46, No. 3, pp. 424–428, March, 1984. 相似文献
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S. C. Athanasiadis A. Chroneos 《Journal of Materials Science: Materials in Electronics》2014,25(10):4273-4277
The investigation of issues involving electromagnetic excitations is motivated by significant applications that include for example radiation from thin wires embedded in layered chiral media and can be extended to many materials issues involving multilayered anisotropic materials with varying conductive and magnetic properties. In this paper we establish relations connecting electromagnetic excitations with multilayered scatterers. In particular we develop a method to describe a multilayered chiral scatterer and apply it to a penetrable chiral sphere. 相似文献
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Assumptions of theoretical laser-induced incandescence (LII) models along with possible effects of high-intensity laser light on soot aggregates and the constituent primary particles are discussed in relation to selection of excitation laser fluence. Ex situ visualization of laser-heated soot by use of transmission electron microscopy reveals significant morphological changes (graphitization) induced by pulsed laser heating. Pulsed laser transmission measurements within a premixed laminar sooting flame suggest that soot vaporization occurs for laser fluences greater than 0.5 J/cm(2) at 1064 nm. Radial LII intensity profiles at different axial heights in a laminar ethylene gas jet diffusion flame reveal a wide range of signal levels depending on the laser fluence that is varied over an eight fold range. Results of double-pulse excitation experiments in which a second laser pulse heats in situ the same soot that was heated by a prior laser pulse are detailed. These two-pulse measurements suggest varying degrees of soot structural change for fluences below and above a vaporization threshold of 0.5 J/cm(2) at 1064 nm. Normalization of the radial-resolved LII signals based on integrated intensities, however, yields self-similar profiles. The self-similarity suggests robustness of LII for accurate relative measurement of soot volume fraction despite the morphological changes induced in the soot, variations in soot aggregate and primary particle size, and local gas temperature. Comparison of LII intensity profiles with soot volume fractions (f(v)) derived by light extinction validates LII for quantitative determination of f(v) upon calibration for laser fluences ranging from 0.09 to 0.73 J/cm(2). 相似文献