共查询到19条相似文献,搜索用时 140 毫秒
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一种场击穿型真空触发开关的触发与导通过程 总被引:2,自引:0,他引:2
真空触发开关TVS(Trggered Vacuum Suitch)是高功率脉冲技术领域的重要开关器件之一,它具有结构紧凑、介质恢复迅速、操作无噪声、工作可靠性高、环境适应性强等优点,在中压领域具有广泛的应用前景.针对场击穿型TVS触发比较困难的特点,在触头表面涂敷TiH2材料,利用TiH2的脱氢产生大量的初始等离子体,可以有效地降低触发电压,提高触发可靠性.设计了一套触发系统和LC振荡主回路来测试TVS样品的开通性能.触发系统输出峰值22 kV、350 A的正脉冲源,系统延时40 μs左右.利用高速摄影拍摄了TVS的燃弧过程.试验结果表明,正极性接线的TVS样品经触发后能有效地开通,触发成功率高,延时分散性比较小,燃弧稳定,能够在小电流过零时产生有效的截流. 相似文献
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真空触发开关的起弧稳定性分析 总被引:4,自引:3,他引:1
真空触发开关(triggered vacuum switch,TVS)是大功率脉冲技术领域的重要开关器件之一,它具有结构紧凑、介质恢复迅速、操作无噪声、工作可靠性高、环境适应性强等优点,在中压领域具有广泛的应用前景.TVS的开通过程本质上是电弧燃烧过程.针对TVS的起弧稳定性,搭建了一套场击穿型TVS的触发和实验系统,从电气特性和图像特性两个方面记录其起弧过程.实验和理论分析表明,触发系统的稳定延时大约40μs,起弧过程持续297μs左右;初始等离子体的不同发展决定着TVS的开通.只有充足的初始等离子体,才能产生一定的鞘层电压,从而不断产生新的阴极斑点,保障起弧的稳定性. 相似文献
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刘静鲜 《中国新技术新产品》2015,(5):33-34
有源电子式电流互感器的母线式电源具有感应电压较高、热耗能过大的缺点,容易对运行工况造成不良影响。本文提出了一种通过控制电路开关快速导通与闭合的磁通调制方式获得稳定电压输出的思想,进行母线式电源的设计。电源的电路设计中包括主绕组与控制绕组两个部分,通过控制绕组的通断与占空比,控制电流互感器中的磁通量,实现对感应电压的控制。在电流互感器中固定一次电流情况下,对调节占空比与通断频率的主绕组感应电压进行仿真与实验,结果证明这种设计方法能够稳定主绕组感应电压,获得较为理想的输出电压,是电流互感器电源设计的有效方法。 相似文献
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为解决传统绝缘电阻与开关导通状态测试仪在装甲车车载电器设备检测时效率低、精度差等问题,设计基于单片机、CPLD和触摸屏的绝缘电阻与开关导通测试仪.系统具有准确迅速实现80路绝缘电阻巡回检测与80路开关导通状态判断的功能,利用TOP242构成反激式开关电源产生200 V/50 V直流测试电压,触摸屏作为人机界面,CPLD完成译码工作以控制继电器开关矩阵动作;加入低通滤波器的放大电路有效提高了系统的抗干扰性能.实验结果表明:该测试仪完全满足装甲车车载设备绝缘电阻和开关导通测试的精度要求,提高了测试效率. 相似文献
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工业过程中大量使用的变频器(variable frequency drive,VFD)在采用传统交流供电时易受到电压暂降影响,传统治理方式存在检测延时、控制复杂等问题。为此,该文从敏感负荷变频器在电网扰动工况下的供电需求量化出发,围绕供电拓扑设计、DC/DC变换器的控制策略及储能单元容量配置等方面,构建一种实用化工业用交-直流级联供电方案。该文利用电压暂降过程中直流供电回路与敏感负荷间的压差自感应控制,实现交-直流供电回路无扰动切换,提高电压暂降治理响应的快速性;采用两相交错并联DC/DC变换器接入集中式储能,减少储能系统纹波系数,并给出两相均流控制方法。最后,通过Matlab/Simulink中的建模仿真与样机的实验测试,验证所提方案能够在交流系统发生不同严重程度电压暂降过程中为各类敏感负荷提供稳定的连续供电,为解决工业敏感用户高品质供电问题提供可实用的新思路。 相似文献
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Kupershtokh A.L. Karpov D.I. Medvedev D.A. Stamatelatos C.P. Charalambakos V.P. Pyrgioti E.C. Agoris D.P. 《Science, Measurement & Technology, IET》2007,1(6):303-311
A new model that can reproduce main stochastic features of partial discharge (PD) activity at AC and DC voltages was proposed. The type of PD activity because of microdischarges in small cavities present in dielectric materials was considered. Three different criteria were used to simulate an initiation of partial discharge inside voids. The simplest criterion of threshold type was used also to describe a decay of plasma in voids and subsequent decrease in conductivity to zero. After AC voltage was applied to solid dielectric, the narrow peaks of current in external circuit were observed in our simulations. Every peak corresponds to a moment of PD in a void. The behaviour of cavities in dielectric liquid under DC voltage was also simulated. In this case, PD activity is possible even under DC voltage because of both elongation of microbubbles present in a liquid and diffusion of charge carriers from the surface of a bubble into a liquid. 相似文献
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Converter transformers play an important role in the high-voltage DC power transmission system. The insulation of these transformers is stressed by both AC and DC voltages. Particle contamination is one of the major problems in insulation structures, as they generate partial discharges. A methodical experimental study was carried out to understand the partial discharge formation because of single macroscopic conducting particle movement in transformer oil at different temperatures under DC voltages using ultra-high-frequency (UHF) technique. It is observed that the single particle moves in the vertical electrode gap under the DC voltage, and generates UHF signal in the range of 1-3 GHz. At high electric fields, the levitated particle sometime floats in the oil medium and as and when the applied voltage is removed, the particle slowly drops down. When it comes in contact with ground electrode, it generates UHF signals with the frequency content lying in the range of 1-3 GHz. Oil breakdown tests were carried out (without any particle in the oil electrode gap) under DC voltages and fast Fourier transform (FFT) analysis of the signal generated by the UHF sensor because of breakdown indicates that the frequency content of the UHF sensor signal lies up to 1 GHz. 相似文献
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M. I. Yalandin A. G. Reutova K. A. Sharypov V. G. Shpak S. A. Shunailov G. A. Mesyats 《Technical Physics Letters》2010,36(9):830-833
A simple method is proposed that makes it possible to determine the moment of injection of a bunch of runaway electrons relative
to a subnanosecond leading front of the accelerating high-voltage pulse applied to the cathode in air-filled diode with inhomogeneous
field. The moment of injection is determined by finding a minimum in dispersion of the time delay between the variable point
of oscilloscope sweep triggering on the instable front of the accelerating voltage pulse and the detected front of the electron
current pulse. 相似文献
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随着新能源发电规模越来越大,输送距离越来越远以及大规模分布式发电和直流负荷的接入,现有的交流电力系统越来越难以满足电力系统发展的需求。由于高压直流输电(high voltage direct current,HVDC)的技术优势,交流电力系统面临的这些挑战,却给直流电力系统的发展带来了新的契机。介绍了欧美各国和我国在高压直流输电系统、中压直流配电系统和低压直流供电系统等不同电压等级直流电力技术的发展现状,分别对高压直流输电技术、中压直流配电技术和低压直流供电技术的应用场景进行了说明,并针对现有交流输电技术的不足,分析了直流电力技术在新能源远距离输电和分布式电源接入等方面的优越性。最后介绍了现有技术水平下直流电力系统发展在关键设备研发、控制保护和标准制定等方面所面临的挑战。 相似文献
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S.A. Cherenshchykov 《Vacuum》2004,73(2):285-289
This paper presents new results on the performance of a special cold-cathode gauge. The use of an AC and DC voltage simultaneously as the power source makes it possible to ignite and sustain a discharge at a significantly lower voltage than normal over a wide pressure range (from 5 to 3×10−6 Pa). The Penning discharge voltage can be as low as 20 V at a pressure of 0.3 Pa and 300 V in high vacuum. For low values of pressure, the discharge current has a monotonously increasing dependence on the gas pressure. If a low RF voltage is applied to a high-voltage DC discharge, the discharge current increases in many times. These discharge properties can be used to improve the performance of devices that use the Penning and other magnetic discharges (total and partial pressure gauges, leak detectors, ion pumps, ion sources and hot plasma sources). A vacuum gauge of this type combines the best features of magnetic discharge and hot cathode ionization gauges. 相似文献
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MAPAN - This paper presents an adapted technique to calibrate the AC voltage divider of AC high-voltage measuring systems up to 200 kV at the Egyptian National Institute of Standards. Two... 相似文献