直流稳压电源的操作过电压及其防护

本文从理论上深入地分析研究了直流稳压电源操作瞬态过电压的物理过程，以及瞬态过电压对微机ＣＭＯＳ元器件所造成的危害；通过反复实验观察，验证结果与理论分析一致。并设计出了相应有效的防护电路，从根本上克服了直流稳压电源操作瞬态过电压对负载的危害。     

田湾核电站扩建工程土石方爆破安全控制

针对田湾核电站5～8号机组土石方工程中前期土石方爆破发生的安全事件，通过现状调查及原因分析，找出爆破飞石产生的主要原因，分别制定了主动防护对策和被动防护对策并加以实施，取得了很好的效果。     

500kV超高压输电线路电磁环境影响因素分析及其防护对策

电磁环境是制约电网建设和发展的一个重要因素。研究输电线路电磁环境影响因素及其防护对策,可以为输电线路的设计提供技术依据,使人们正确认识输电线路电磁环境并合理选择防护对策。为此,笔者基于等效电荷法,研究了输电线路对地高度、双回路导线相序布置、等效半径、单回路导线布置方式、相间距离等因素对500kV超高压输电电磁环境的影响,并根据研究结论和相关研究成果提出了主动防护和被动防护等具体的防护对策。     

动力电池热扩散防护方法研究与分析

电动汽车安全，是目前整个新能源汽车行业以及相关部门单位十分重视的问题。车用电池系统重要的安全性要求之一是热失控触发后有效阻燃或减缓热蔓延的速度。电动车行业已形成相对完善的标准，对于热扩散发生对司乘保护有明确的时间要求。采用理论研究、结合实验测试(含电池、模组，电池包测试)的研究方法，针对电池在结构上进行优化设计，通过对比测试及拆解分析，验证一种有效的软包电池热扩散的防护方法，为后续开发设计电池系统的热扩散防护方案提供参考依据。     

“断零”解析与对策研究

从"断零"机理分析,证明是故障点在供电端的三相电路故障,法定职责方是供电部门,只能供电端防护,用电端防护是徒劳的,现行标准措施存在错误。研究了"断零"防护新方案,并提出对策与修订建议。     

变电站受导电纤维弹打击的隐患和防护对策

导电纤维弹是近年来出现的专门攻击电力系统的软杀伤武器。文章介绍了导电纤维弹的作战性能、破坏机理以及战斗应用方式，并以南京东善桥500kV变电站为研究对象，详细探讨了在导电纤维弹打击下变电站存在的安全隐患，提出采用重点防护和整体防护相结合的对策，并利用FLUENT软件对防护区域进行了数值模拟。     

500kV输电线路电场强度测量与计算分析

研究输电线路电磁环境影响因素及其防护对策,可以为输电线路的设计提供技术依据,使人们正确认识输电线路电磁环境并合理选择防护对策。笔者首先进行架空输电线路物理模型的建立和电场计算,然后采用电磁分析仪PMM8053B与工频电磁场探头EHP-50C,对焦作500 kV输电线路某段的实际电场强度进行实地测量,通过MATLAB仿真软件验证了理论模型和实验的相符。在此基础上,对影响高压输电线路电场强度的多种因素进行模拟计算,分析指出适当减少相间距以及采用倒三角排列导线可减小输电线路下方的电场强度。     

ECRH负高压脉冲电源系统的电磁兼容性研究

负高压脉冲电源是ECRH系统最重要的组成部分之一，其工作的安全与可靠性直接影响整个系统运行。分析了空间电磁干扰的基本理论，针对空间电磁干扰与其他干扰源，从系统的安全防护、信号传输、制作工艺等方面，提出了几种抗干扰措施。仿真与实验表明，提出的几种抗干扰措施具有较明显的抑制干扰的作用。     

能源互联网环境下分布式能源站的信息安全防护

能源互联网中分布式能源站的建设引入网络信息技术和标准数据传输通信协议，也将导致其面临信息安全威胁和风险。信息安全是保证能源互联网环境下分布式能源站发展的重要基石，建设安全的分布式能源站是能源互联网发展的必然趋势。从能源电力系统面临的信息安全威胁角度出发，设计了能源互联网环境下分布式能源站的体系架构，分析了分布式能源站信息安全防护对策，并通过构建的分布式能源站平台进行信息安全防护配置和应用实施分析，为分布式能源站的信息安全提供保障。     

电磁瞬态多级防护技术研究

对电磁瞬态 (电涌 )的器件防护技术进行了研究。根据电涌多级防护的基本要求 ,利用电路波过程理论 ,推导了两级防护电路的电压和电流波的计算公式。在此基础上 ,对两级防护的动态特性进行计算分析。最后采用 EMTP软件对多级防护的实例进行仿真     

Parameters influencing breakdown characteristics of vacuum gapsduring spark conditioning

Experiments have been made to identify the key parameters in the increase of the breakdown strength of a vacuum gap through repetitive breakdowns. The current-voltage waveforms were observed, the residual stress in electrodes was measured, and the chemical composition of the electrode surfaces and the energy of the valence-band electrons were analyzed. These experiments revealed that prebreakdown currents (field emission currents) were sometimes observed and sometimes not. The residual stress before and after 500 breakdowns changed significantly. X-ray photoelectron spectroscopy analysis before and after 500 breakdowns showed that the spectral lines of oxygen and carbon due to contaminants on the electrode surface were completely removed and the copper ones appeared clearly after 500 breakdowns. The valence-band electron energy spectrum of the anode after 500 breakdowns shifted towards the lower binding energy to almost coincide with the theoretical spectrum, while the energy spectrum for the cathode shifted towards sometimes higher and sometimes lower binding energy     

On priorities of cathode and anode contaminations in triggering the short-pulsed voltage breakdown in vacuum

Modern theoretical notations on electrical breakdown in vacuum consider cathode triggering mechanisms to be most responsible on short-pulsed (<1 /spl mu/s) breakdowns while anode mechanisms to be responsible in a part on DC and long-pulsed breakdowns. Following those notations, we tried to reveal conditions at which either mechanism steps aside to another one. The study involved several experimental techniques including the anode-probe surface scanning, pulsed electron-beam surface melting in vacuum for surface cleaning, and intentional dust particle contamination of electrode surfaces. Breakdown tests were performed using a pulser capable of producing 220 kV quasi-square pulses that were adjustable to /spl sim/30 to 80 ns pulse length. Our experiments showed that cathode emission sites are responsible for breakdowns at relatively low hold-off fields. At higher electric fields of up to 1 MV/cm, the anode share in the mechanism of triggering breakdown becomes probably more significant than the cathode mechanism.     

Dielectric spectroscopy in time and frequency domain for HV power equipment. I. Theoretical considerations

Most dangerous breakdowns are caused by the aging effects of HV insulation systems used within HV components, and there is still a lack of appropriate tools to diagnose such systems non-destructively and reliably in the field. This review introduces the theoretical background of dielectric spectroscopy in the time and frequency domains and provides an overview about the specific measuring methods based on this background. The specific methods treated are used for diagnosing electric insulation materials used in power engineering. It indicates that some of these methods may not be sufficient to gain full information about the actual conditions of a test object and that either measurements of polarization and depolarization currents (PDC in the time domain or measurements of C-tan/spl delta/ values (or complex permittivity) in the frequency domain (FDS) should be preferred to obtain a "dielectric response function" which offers much more information to judge the actual state of an insulation material or system.     

FANUC数控设备的常见故障及排除实例

文章介绍了FANUC数控设备常见故障的几个具体实例及排除方法。     

维护蓄热式加热炉仪表几点经验

通过对蓄热式加热炉仪表的工作原理分析,并从生产实践中总结出1套对加热炉仪表常见故障的判断和排除方法。缩短了仪表维护时间,保证加热炉的正常生产。     

对Windows中输入法问题的处理

计算机使用过程中，多数用户经常遇到输入法设置问题，影响正常文字的输入．通过对Windows 2000／XP／98操作系统下常见输入法故障的分析，介绍了排除输入法故障的简易方法．     

网络计算机的维护与管理

从计算机操作系统及软件故障、计算机到网络的连接失败、安装备份盘、克隆主分区等方面，对计算机故障进行了分析，目的是让使用者了解一般网络计算机故障的解决办法。     

PLC控制系统的故障检测与显示

介绍了可编程控制器控制系统运行中常见故障的产生，检测及显示，对于复杂的控制系统，应对故障进行分级处理，把那些影响重大的故障作为检测的重点。并用PLC控制的加热炉上料系统的故障检测实例加以说明。     

Relation between breakdown mode and location in short-channelnMOSFETs and its impact on reliability specifications

A method to determine the breakdown position in short channel nMOSFETs is introduced. We find that soft breakdown occurs exclusively in the transistor channel, while the hardest circuit-killing breakdowns occur above the source and drain extension regions. Since these breakdowns make up only a small fraction of all breakdowns, a relaxation of the reliability specification is possible     

Change in dielectric strength of vacuum interrupters at reduced service life

The dielectric strengths of two samples of the same type of vacuum interrupter are compared. One vacuum interrupter is a new and has not been tested for switching ability after manufacturing and the other is a vacuum interrupter with a 70% reduced service life. Tests of the dielectric strength are conducted using a standard lighting pulse. Studies have shown that electric breakdowns behind the front of a lighting pulse are caused by electric breakdowns in the screen system of the vacuum interrupter. Possible reasons for the decrease in the dialectric strength of the screen system are discussed.