油浸变压器常见事故的处理及预防措施

变压器漏油和起火是油浸变压器在运行过程中的常见问题,为此,针对变压器结构设计不合理、制造工艺水平不高、材质选用不当及现场安装操作不规范等几方面因素提出相应的处理方法及预防措施,以解决变压器渗漏油及防火问题,保证电网的安全稳定运行。     

配电变压器防雷保护的研究

由于正、逆变换过电压的作用,配电变压器的雷击损坏率一直很高,低压用电设备因雷击损坏的情况也很严重。对此,进行了更进一步的研究,并提出了一种新的配电变压器防雷保护方法。通过在现场5年的大量运行,证明其防雷效果非常理想。     

银川东750kV变电站避雷器不拆引线直流试验方法

介绍了在银川东750kV变电站330kv和750kV氧化锌避雷器停电高压试验中,不拆除设备引线进行U1mA及0．75U1A下泄漏电流的测试方法。     

山西电网线路雷击跳闸原因分析及防范措施

针对2011年山西电网110 kV及以上输电线路雷击跳闸故障,从地形地貌、保护角、接地电阻等方面分析了故障产生的原因,剖析了防雷工作中存在的问题,并从规划设计、建设施工、生产运维方面提出了相应的防范措施。     

110kV变压器中性点雷击闪络故障分析及防治措施

为获得雷电流冲击下110 k V变压器不接地中性点上的过电压,采用线饼模型对110 k V变压器绕组进行建模,并用PSCAD仿真软件对该模型进行仿真计算。利用该模型对广州地区110 k V变压器中性点击穿事故进行仿真分析,结果表明对变压器中性点仅加装放电间隙不足以防止雷电侵害,并且雷电波入侵变压器时中性点故障率高达到0.686次/年,说明需要结合其他防护措施对这一地区变压器中性点进行保护。根据仿真结果提出采用130 mm的间隙并联Y1.5W-72/186避雷器实施改造措施。     

Distribution arrester outages caused by lightning backflow current flowing from customer's facility into power distribution lines

Direct lightning strokes are considered to be a main cause of damage to surge arresters on power distribution lines. Recently, lightning performance of distribution lines has been observed using still cameras, and lightning‐caused distribution outages on hilltop areas on the coast of the Sea of Japan have been investigated. This research has shown a possibility that lightning backflow current flowing from customer facilities into distribution lines causes damage to surge arresters on the distribution lines. We have investigated the lightning backflow current flowing from customer facilities into distribution lines as a cause of damage to surge arresters. The main results are as follows: (1) The electric charge of the backflow current flowing into distribution lines is more than 60% of that of the lightning stroke current. (2) If the grounding resistance of the customer's facility is not low, the failure rates of a surge arrester caused by backflow current due to winter lightning is more than 90% of that caused by direct lightning strokes. © 1999 Scripta Technica, Electr Eng Jpn, 126(3): 9–20, 1999     

配电线路防雷与接地措施

雷电对电气系统中的配网危害十分严重,因此,采取有效的防雷、接地措施十分重要。就配电系统中线路和变压器的防雷、接地问题进行了分析,并提出了相应的应对措施,为设计和运行维护人员提供一定的参考。     

Relation of insulation resistance and deteriorated ratio ofreference voltage of oil-immersed surge arrester elements enclosed inpole transformers

About ten years have passed since oil immersed surge arrester elements enclosed in 6.6 kV pole transformers were first used. At present, technical developments are being demanded to judge the soundness of these oil immersed surge arrester elements by a simple method, allowing one to judge easily whether these elements can be used or not onsite. The authors empirically investigated the correlation between the insulation resistance and the deteriorated ratio of the reference voltage of these oil-immersed surge arrester elements. It was found that the deterioration of the oil-immersed surge arrester elements can be detected by measuring the insulation resistance     

浅谈油浸配电变压器的安全与环保

从美加大停电事件,关注国内外配电变压器存在的安全隐患与环境保护问题,并分析农网和城网大力改造后仍存在的诸多问题;借鉴国外的解决方法,提出利用新材料、新技术制造新型配变,即杜邦NOMEX 绝缘系统β液浸变压器,此种新型液变,将大大改变目前的配变状况和消除配变安全隐患和环保问题.     

山区高压输电线路雷击跳闸分析和改进措施

针对近年来宁波地区处于山区的输电线路雷雨季节频遭雷击引起跳闸故障,分析跳闸原因,为提高线路耐雷水平减少雷击跳闸故障,提出防雷改进措施,提高了电网供电可靠性。     

Effective lightning protection schemes for distribution line

The causes of lightning outage are subdivided into direct lightning strokes and induced lightning strokes, which are identified by the characteristics of the lightning overvoltage. In the past, lightning protection devices were directed mainly toward the latter, and attention has been focused on the installation of lightning protection devices, ground wires, and reinforcement of insulators. However, lightning outages continue to occur. Thus it is extremely important to clarify the fault characteristics of lightning surges and to study the effectiveness of various lightning protection devices by considering both direct lightning stroke and induced lightning stroke in order to prevent lightning outage in the future. In this research, the electromagnetic transients program (EMTP) has been applied to the direct lightning stroke, and the induced lightning outage analysis program for multiple conductor systems has been applied to the induced lightning stroke to study the effectiveness of lightning protection devices provided by combination of various lightning protection devices. The most effective lightning protection schemes are analyzed and evaluated based on verification tests on the full scale models as well as economic considerations.     

无汞锌粉中氧化锌的测定

使用碘试剂来分离提取无汞锌粉中的氧化锌,采用原子吸收分光光度法对提取液中的锌元素进行测定。并分别比较了氯化铵 氢氧化铵、乙酸铵、碘3种介质溶解提取氧化锌的试验。试验结果表明:碘试剂提取法较好,测定结果较为符合实际情况。此法回收率为92.31%～104.5%之间,相对标准偏差为5.5%。     

Statistical analysis of lightning performance of distribution lines based on observation in fields

Because of the lower insulation level than for transmission lines, in this study on lightning protection design of distribution lines, not only direct lightning strokes but also induced voltages caused by nearby strokes must be taken into account. Thus, it is necessary to grasp the frequency of occurrence of lightning phenomena around distribution lines. For this aim, lightning phenomena on TEPCO's distribution lines in use were continuously observed for 6 years (1996 to 2001). Through this observation, new interesting statistical data that can be a useful basis for rationalization of lightning protection design of distribution lines were obtained. Two hundred and four lightning strokes were observed through the six‐year period. Probability of occurrence of a direct stroke was 22% (45 direct strokes were obtained). The fact that in 47% of direct strokes the electric outage did not occur is very interesting. Moreover, the value of surge discharge current of the arrester in the case of nearby stroke is the basis for conventional theory of grounding system. Therefore, statistical analysis of ZnO discharging current in the case of nearby strokes was carried out. As a result, in the case of nearby strokes, 5% value of cumulative frequency of discharging current is 0.5 kA. This value is half the conventional data. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 8–16, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20180     

广西某地区配电线路雷害事故及防雷措施研究

针对广西某地区近年来配电线路频发雷害事故这一现状,通过实地调查,并结合实验室的试验结果,对该地区配电线路存在的问题进行了分析,认为线路上存在大量的"零值"、"劣值"绝缘子,线路采用不当的防雷措施,配电变压器的低压侧缺少防雷保护措施是造成雷害事故频发的主要原因。研究表明:采用清除线路上的"零值"、"劣值"绝缘子,在线路易被雷击段处装设线路避雷器,拆除线路上不当的防雷设备,降低进线段杆塔接地电阻,完善配电变压器低压侧防雷保护等改造措施,可以降低雷害事故的发生概率,大大提高配电线路运行的安全可靠性。     

Evaluation of surge-transferred overvoltages in distribution transformers

The paper presents an analysis of very fast-transient overvoltages that occur because of the capacitive surge transfer from the high-voltage (HV) transformer winding to the low-voltage (LV) transformer winding.     

基于数字图像技术的锌氧电池正极材料分布模拟

采用数字图像的处理方法模拟了锌氧电池正极内部不同成分的分布情况,直观了解其内部各材料的分布情况及连通性,也可对电极内部所发生的化学催化、导电和电解液浸入等过程进行更详细地解释,同时有利于设计不同优势的正极,并对其催化性、浸液量及导电性等性能进行验证。研究结果表明,当石墨比例增大时,电极的导电性增强,当活性炭的含量增加时,电极的吸液能力增强。当乙炔黑、石墨、二氧化锰、活性炭的质量比为1∶1∶2∶4时,二氧化锰的催化区域最适宜。     

10 kV配变支柱型复合氧化锌避雷器的改进与应用

通过对10 kV普通支柱型避雷器的不断改进,研制出集支柱绝缘子、穿刺线夹、接地环、避雷器四功能为一体的新式配变支柱型复合氧化锌避雷器,简化了配变台区装置形式,提高了施工效率,方便了运行操作,减少了运行与检修中的停电时间和范围,在德清配电网配电台区建设中已推广应用。     

油浸自冷式配电变压器换热特性的数值模拟研究

为得到变压器设计者所关心的变压器内部绝缘油的速度分布和温度分布数据,运用FLU-ENT软件模拟油浸自冷式配电变压器内部换热特性.根据变压器实体数据,建立一个简化模型,采用RNG k-ε模型作为湍流模型,近壁处采用双层模型处理,得到了变压器内部绝缘油的速度和温度的分布情况,并与测量值进行对比分析,验证了数值模拟研究的正确性和可行性.数值模拟结果为油浸式配电变压器结构的优化设计与故障诊断提供了理论依据.     

氧化锌避雷器现状及存在问题分析

介绍了国内外氧化锌（ZnO）非线性电阻片技术的发展过程和改良成果。以及氧化锌避雷器（MOA）的工作原理、结构和特性参数。结合广东电网公司揭阳供电局220kV普宁变电站的MOA故障案例进行分析,指出MOA在过电压防护、密封材料老化、绝缘套污染等方面还存在问题．认为选择MOA主要控制2个方面：必要的过电压保护水平和足够的使用寿命。     

大型油浸式风冷变压器绕组温度场及流场分析

阐述了油浸式风冷变压器绕组的热源和冷却结构,采用热-流耦合方法建立了温度场和绝缘油流场的有限元模型,通过fluent软件对1台180 MVA油浸风冷变压器进行计算,得到了绕组稳态温度分布及油流分布,并分析了挡油板位置及数量对绕组温度场及油流分布的影响.计算结果表明,在绕组辐向加油道和加挡油板均会起到较好的散热效果,在端部设置较少的挡油板会比沿绕组轴向均匀设置挡油板散热效果好.