一种亚纳秒高压脉冲源的研制

本文对一种以亚纳秒高压脉冲放电管为主要元件的脉冲产生电路进行了计算和试验研究,给出了电路的结构参数及选取原则.实验表明所研制的高压脉冲发生电路可产生上升时间小于500ps,幅值不低于4kV的亚纳秒高压脉冲信号,并且具有放电稳定、重复性好、频谱范围广的特点,可作为研究GIS和电力变压器中局部放电信号超高频特性用的信号源.     

亚纳秒高压脉冲发生器的研制及仿真

以高压脉冲放电管为开关元件研制了一种亚纳妙高压脉冲发生器,实验和仿真表明该发生器可产生上升时间为360 ps,幅值不低于4 kV的亚纳秒高压脉冲信号,并且具有放电稳定、重复性好的特点,可作为研究GIS和电力变压器中局部放电信号超高频特性用的信号源。     

亚纳秒脉冲用于智能GIS局放IED性能试验的可行性研究

气体绝缘金属封闭开关(GIS)以其占地面积小、可靠性高而在电力系统中得到了广泛的应用,但GIS长期运行过程中不可避免的会产生各种各样的内部绝缘缺陷,并伴随产生局部放电现象,甚至会引起系统故障,因此为保障系统可靠运行,对GIS进行局部放电在线监测具有重要意义。局部放电检测具有电学、声学、化学和光学等多种检测方法,其中电学测量手段主要有脉冲电流法和特高频检测法(ultra-high frequency,UHF)。UHF法测量局部放电辐射出来的电磁波的电场强度,而脉冲电流法测量局部放电引起的视在电荷。UHF法相较于脉冲电流法可提取信号中的特高频成分,具有灵敏度高,可带电监测,智能GIS局放IED(智能电子设备)采用UHF+IED的局放监测方法。文中研究了采用上升沿时间为253.75 ps、半高宽约为1.15 ns、最大峰值电压为532 V(0 dB)的亚纳秒脉冲进行智能GIS进行局放IED性能试验的可行性,结果表明:UHF传感器输出信号稳定;局放IED测量结果与亚纳秒脉冲峰值成正相关关系而非线性关系;当亚纳秒脉冲为30～50dB时,IED测量结果分散性较大;因此亚纳秒脉冲信号可用于进行智能GIS局放IED性能试验。     

一种用于脱硫硝的毫微滗脉冲电源的研制

电晕法烟气脱硫脱硝要求快速窄脉冲供电方式，介绍了一种新颖毫微秒波头脉冲电源，其输出电压波形，前沿上升时间小于２０ｎｓ，脉宽小于１００ｎｓ，基压和脉冲幅值分别可调并且脉冲能量转移率和电源自射的能量效率也分别达到９５％和７０％以上。     

激光触发开关同步特性的研究

利用高压电容放电开关试验平台,对两个氮气气体开关在266nm脉冲激光触发作用下开关的工作特性进行了研究。实验结果表明:两个开关的延时、抖动随激光能量的增加、欠压比的增大而减小。激光能量5.5mJ时,每个开关电压抖动时间达到了亚纳秒量级,但是两个开关的延时时间差大于1ns;当激光能量大于8mJ时,两开关导通的延时时间差达到了亚纳秒量级,可认为两开关同步导通。     

形成高压纳秒脉冲仿真线的设计

本文叙述了高低阻抗线和螺旋带传输线的设计原则，并利用这二种仿真线在同轴５０Ω负载上获得了快前沿的高压纳秒脉冲。实测结果表明，脉冲的上升时间小于０．４ｎｓ，宽度从１．６５～１０．６ｎｓ可变，幅值大于２０００Ｖ。     

汞膜形变对亚ns脉冲放电管击穿电压的影响

为研究电源电压对亚纳秒脉冲放电管输出脉冲幅度的影响,建立了基于汞膜电极放电管和无汞放电管的高压亚纳秒脉冲发生器及其参数测试装置。实验中观测到汞膜电极放电管的输出脉冲幅度随电源电压增加而明显增加的现象,但无汞放电管的输出脉冲幅度与电源电压的关系并不明显;用显微镜观测到汞膜电极放电管汞膜形变的现象。用示波器测量2种放电管动态击穿电压的结果表明,只有汞膜电极放电管的动态击穿电压随电源电压的升高而明显上升,汞膜形变是影响汞膜电极放电管击穿电压的主要原因,而且汞膜形变滞后于充电过程。在此基础上,采用汞膜电极放电管,连续调节电源电压,实现了单独、连续地控制脉冲幅度。     

一种紧凑的高压毫微秒脉冲信号发生器

对一种紧凑的高压毫微秒脉冲信号发生器的整体结构和各部分工作原理作了较详细介绍。并对调试中出现的一系列问题进行了分析，高压毫微秒脉冲发生器由电子元件构成控制部分，采用了北京真空电子技术研究所的新型触发管作为放电开关，高压充电部分利用“反峰充电”原理完成。整机抗干扰能力强，能产生幅值在２５００Ｖ以上的稳定高压毫微秒脉冲，波形指标是脉宽１００ｎｓ，上升沿时间小于１０ｎｓ，平顶下降小于１０％，可以作为方波     

高压GaAs亚纳秒光电导开关的实验研究

报道了用全固态绝缘结构研制的半绝缘GaAs光电导开关产生高压亚纳秒电脉冲的性能和测试结果。分别用ns、ps激光脉冲触发开关的测试表明，开关的暗态维持电场达35KV/CM，输出电流脉冲上升时间约500ps，达亚纳秒量级。测量了高倍增开关的光电阈值曲线，其最小触发电场阈值≥4.1kv/cm。开关输出电磁脉冲无晃动。3mm电极间隙开关2500v偏置下，入射能量为8μj时获得线性波形，在48μj时获得Look-on波形。     

强脉冲技术应用于肾结石体外粉碎机

对ｎｓ级脉冲技术应用于肾结石体外粉碎技术进行了试验研究，分析了压力波陡度、脉宽对碎石及疗效的影响。     

基于绝缘薄膜开关的快前沿高压方波发生器

本文对基于绝缘薄膜开关的方波脉冲发生器的设计及整体结构作了较详细的介绍,并分析了方波发生器放电回路杂散数对方波前沿的影响。整机可产生幅值1．5－8kV、前沿小于1．5ns、脉宽40ns的方波脉冲。     

Compact Subnanosecond Pulse Generator Using Avalanche Transistors for Cell Electroperturbation Studies

Research on the electroperturbation effects of ultrashort high field pulses in cancer cells requires subnanosecond rise time, high voltage pulses delivered to low impedance biological loads. Here we present a compact solid-state pulse generator developed for this application. The pulse is generated by switching a chain of avalanche transistors configured as a tapered transmission line from high voltage to ground. The system features a built in 1400:1 capacitively compensated resistive voltage divider. The divider, with a 3 dB point at 910 MHz, overcomes challenges in the direct measurement of the high frequency components of the output pulse. The generator is capable of producing a 0.8 ns rise time, 1.3 ns wide, 1.1 kV pulse into a 50 Omega load at a maximum repetition rate of 200 kHz. Techniques to implement physical layouting strategies to achieve subnanosecond rise times are outlined. Problems faced in integrating the subnanosecond pulse generator with a biological load are discussed. This pulse generator will be used in experiments aimed at electromanipulation of intracellular biomolecular structures.     

陡前沿纳秒脉冲电源的研制

介绍一种陡脉冲前沿的脉冲电源系统,其脉冲前沿<６０ｎｓ,脉冲半高宽约２５０ｎｓ,重复频率０～２００Ｈｚ可调,工作电压７０～１２０ｋＶ,系统效率＞７０％,累计运行时间已>Ｍ２００ｈ,它是电厂烟气脱硫工程的关键技术。     

Compact, Nanosecond, High Repetition Rate, Pulse Generator for Bioelectric Studies

The high dielectric strength and high permittivity of water allow for its use for energy storage and switching in compact pulse power systems. A 10-Omega pulse generator with flowing water as dielectric and as the switching medium is presented here. It can provide a 10-ns pulse with a risetime of approximately 2 ns and an amplitude of up to 35 kV into a matched load. The system was operated in burst mode with repetition rates of up to 400 Hz, limited by the charging power supply. For a switch with two pin electrodes, strong electrode erosion limits the use of the pulser to less than 1,000 pulses before electrode readjustment is necessary. A considerable reduction of the erosion effect on breakdown voltage was obtained with coaxial electrodes. The pulse generator was used to study the effect of the repetition rate (or the time between successive pulses) on the viability of B16 murine melanoma cells.     

Optimization of a low jitter, 50 kV, 100 Hz triggered spark gap with high pressure gas mixtures

Recent research efforts at Texas Tech University on impulse antenna phased array has needed to develop a reliable high voltage, high repetition rate switch that will operate with ultra low jitter. An ideal jitter of a small fraction of the risetime is required to accurately synchronize the array to steer and preserve the risetime of the radiated pulse. In [1], we showed the initial test system with sub-ns results for operations in different gases and gas mixtures. This paper discusses in detail 50 kV, 100 Hz switch operations with different gases. The effects of gases and gas mixtures have on switch performance which includes recovery rate and in particular jitter will be investigated. Gases tested include, dry air, H², N², and SF₆, as well as H₂-N₂, and N₂-SF₆ gas mixtures. Switch jitter as a result of triggering conditions is discussed, also including a comprehensive evaluation of jitter as a function of formative delay in the various gases. The temperature of gas and its effects on switch jitter is also documented in this paper. A 50 Ω, 1 nF pulse forming line is charged to 50 kV and provides the low inductance voltage source to test the different gases. Triggering is provided by a solid state opening switch voltage source that supplies ~150 kV, 10 ns risetime pulses at a rep rate up to 100 Hz in burst mode. A hermetically sealed spark gap with a Kel-F - PCTFE (PolyChloroTriFluoroEthylene) lining is used to house the switch and high pressure gas.     

The effects of steep-front, short-duration impulses on powerdistribution components

A line-type pulser has been developed to test the effects of steep-front, short-duration (SFSD) pulses on distribution components. The risetime is 50-100 ns and the pulse duration is on the order of 300 ns. Terminators often shattered or punctured rather than flashing over. The insulator flashover voltage is approximately 1.5 times CFO for standard lightning impulses. Arresters exhibit an inductive character, with the SFSD peak voltage at 10 kA approximately 4-5 times the 8-pulse×20-μs 10 kA discharge voltage. Polyethylene insulated cable has a characteristic degradation in which failure voltage decreases with number of SFSD pulses     

Coaxial magnetic pulse compression system to generate fast‐rising pulsed power

A fast‐rising pulsed power generator (PPG) using a coaxial magnetic pulse compression (MPC) system has been developed. Two kinds of magnetic cores, a Co‐based amorphous metal and a nanocrystalline Fe‐based soft magnetic metal, have been used in the coaxial MPC system to evaluate losses of magnetic cores and leakage current of a saturable inductor. The PPG produced a pulsed‐high‐current of 3.7 kA with a risetime of 7 ns (20–80%) at a repetition frequency of 1000 pulses per second. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Dielectric Surface Flashover at Atmospheric Conditions with Unipolar Pulsed Voltage Excitation

Dielectric surface flashover along insulators in atmospheric conditions has only been empirically characterized over the years. The underlying physics involved in atmospheric flashover has yet to be understood, where parameters such as background gas, humidity, surface roughness, and temporal characteristics of the applied voltage play a role. Understanding the fundamental physical mechanisms and the extent to which these parameters influence the discharge behavior is vital to characterizing and modeling surface flashover for various structures and conditions. A solid state high voltage pulser with an adjustable pulse width of ~500 ns at FWHM and amplitudes in excess of 30 kV was developed to replicate the non-standard temporal shape of the transient voltage observed inside a rebar enforced building during a lightning strike. Based on experimental results, the phenomenology of pulsed unipolar surface flashover is discussed, with the emphasis on the influence of external parameters (applied voltage pulse shape/risetime, environment, UV illumination, humidity, etc.) on spatial and temporal discharge channel behavior.     

变压器油中局部放电信号超高频特性的研究

理论分析表明，局部放电信号所激发的电磁波具有很宽的频谱，它以TEM波的形式向外传播。本文通过实验模拟的方法研究了变压器油中的局部放电脉冲电流波形及所辐射的电磁波特性，实验结果表明，变压器油中的局部放电电流脉冲具有极块的上升沿，能激励起1．5GHz以上的超高频电磁波，它可以通过超高频传感器加以耦合接收，这就为进一步研究超高频检测技术在电力变压器中的应用提供了依据。