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M. Ishida Y. Ikeda N. Naohara H. Mitsui R. Kumazawa T. Kuroki 《Electrical Engineering in Japan》1996,116(3):14-28
Development of sodium-immersed-type Electromagnetic Pumps (EMP) is expected to improve reliability, safety, maintainability, and construction cost of the Fast Breeder Reactor (FBR) compared with the conventional mechanical pumps. To realize the EMP, establishment of a high-temperature-resistant electrical insulating system is indispensable. A mica-alumina combination is selected for the insulating system at temperatures higher than 500°C. Using this insulating system, an aging pretest was performed. The aging condition was to apply 1.5-kV ac voltage in the nitrogen atmosphere at 550°C for 4000 hours. The dielectric properties before and after the aging were measured to understand the tendency of temporal change in the aging. In this result, the dielectric performance after aging was improved compared with the initial performance. The curious phenomenon was clarified to be caused by a decrease of organic component in the insulation, which remained due to incomplete burning. Also, the possibility of thermal runaway was considered to be higher as a dielectric breakdown mechanism. 相似文献
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在实践经验的基础上,分析了我国匝间绝缘短路的主要原因,提出在匝间绝缘的设计,制造工艺及耐压试验等工序采取合理措施,以提高匝间绝缘的可靠性。 相似文献
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针对高压电机定子主绝缘减薄后电场的分布问题,本文以YKK400 -6(690 kW)中型高压异步电机为例,建立定子绕组静电场的计算模型.在边界条件不变的基础上,通过对场强最大值及电场集中系数分析计算,对定子绕组主绝缘进行减薄处理,并结合设计要求给出了主绝缘角部合理的圆角半径.在电场计算的基础上对主绝缘减薄前后的线圈进行介质损耗角正切与瞬时工频击穿电压试验.结果表明,新的绝缘结构满足要求.本文可为电机定子主绝缘的减薄及绝缘结构设计提供理论依据.同时也可达到提高电机效率的目的. 相似文献
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高压交联聚乙烯(XLPE)电力电缆的绝缘老化状态关系到供电可靠性,故电缆绝缘老化状态检测及评价方法的研究意义重大。对于高压电缆的绝缘老化状态检测及评价,国内外已有相关研究成果,文中总结了目前常用的高压电缆绝缘状态离线、在线检测及评价方法。离线检测手段准确性高,但不适于对在役电缆进行大面积取样检测;在线监测的环境干扰因素太多,存在的干扰会对监测结果产生影响,有一定检测局限性,且缺乏大量的实验数据支撑;而对于电缆绝缘老化状态评价方法,尚未有广泛认可的评价标准和体系。文中在总结概述现有方法的基础上,提出了目前电缆老化绝缘状态综合评价方法存在的难点及未来电缆绝缘老化评价研究可提升的方向。 相似文献
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一般来说,托卡马克(EAST)装置中的NBI加热系统都是利用Snubber来实现保护的。为了优化Snubber的结构,通常都给其添加一个偏置直流源,将Snubber的性能维持在BH曲线的负饱和点附近,这样能使Snubber的质量减小一半。而目前普遍使用的偏置直流源是将50/60 Hz的交流电经过高压隔离变压器变压后整流直接得到。50/60 Hz的高压隔离变压器体积大、质量重,将带来移动不便和占用大量空间等缺点,如将50/60 Hz变为高频后经高频高压隔离变压器处理,这一问题就能得到解决。基于高频高压技术进行了EAST Snubber高压隔离偏置电源的设计与实验研究。 相似文献
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Optimization criterion is found for insulators under conditions of pollution and moistening to achieve maximal electrical strength for a working voltage of 50 V. Transition to the strong overvoltage limitation (the necessary R and D and economic premises are now available to implement this limitation) will make it possible to significantly reduce the dimensions of the superhigh (SHV) and ultrahigh voltage (HHV) devices at the natural insulation level. 相似文献
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Koichiro Nakanishi Shigeto Fujita Hiroshi Kurita Akio Kishi Taketoshi Hasegawa Yoshikazu Shibuya 《Electrical Engineering in Japan》2000,132(4):45-52
Switching operations in gas insulated switchgear (GIS) can generate very fast transient overvoltages (VFTO) which propagate in the GIS with little attenuation. When a transformer is directly connected to the GIS through a gas/oil bushing, the VFTO can enter the transformer and excite the voltage oscillation in the windings. In the paper, we firstly show a resonance phenomenon due to the superposition of the traveling waves which was found in the experiments using the coil windings of a 500 kV transformer. The fundamental resonance frequency ranged at about 2 MHz, and its voltage at the interturn (turn‐to‐turn) of the coil could reach 0.25 times of the applied voltage in the worst case. Secondly, the electrical breakdown properties of interturn insulation in oil were studied, applying the unipolar and bipolar voltages with 2 MHz oscillatory frequency. The breakdown voltages at the unipolar and bipolar VFT oscillatory stresses were about 1.25 and 1.40 times higher than that at the standard lighting impulse, respectively. We discuss the experimental breakdown stresses with the ones estimated from the analysis of VFTO in the transformer windings and also show the methods to cope with the VFTO. © 2000 Scripta Technica, Electr Eng Jpn, 132(4): 45–52, 2000 相似文献
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在电网中,高压并联电抗器的主要作用是大量补偿线路充电无功,起平衡系统无功潮流分布、改善功率因数和调压的作用。借助PUM装置的高精度同步采集和动态过程记录功能,对宁夏电网第一次对高压并联电抗器投退的动态全过程进行测试分析。全面了解和掌握330kV安固线加装高抗后投退时对宁安变330kV母线电压的影响,并对330kV安固线上安装60Mvar高压并联电抗器的补偿度问题进行了计算验证。 相似文献
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对供电企业高压电气试验中所碰到的一些问题进行了归纳、分类与分析,并探讨如何避免和解决这些问题提出了相应的措施 相似文献
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回复电压法能有效诊断变压器油纸绝缘的状态,但测量时间过长,由此提出通过单次加压建立的极化在不同去极化时间段内的电压响应特性进行绝缘诊断的方法,省去多次加压的过程,节省了测量时间;实验研究了不同受潮状态的变压器油纸绝缘介质在不同去极化时间段的电压响应特性,结果表明,充电2000s后首次放电0.1s的电压响应初始斜率随绝缘受潮程度的增加而增大,可作为评估其受潮状态的特征量;同时通过频域分析仪测得介质的直流电导率,将其与根据首次放电初始斜率计算获得的极化电导率进行对比分析,进一步验证了该特征量的有效性。本文提出的测量方法为应用电压响应法现场快速诊断变压器油纸绝缘的受潮状态提供了一种新的研究思路。 相似文献
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在气体绝缘金属封闭输电线路(GIL)条件下的电磁式电压互感器误差校验中,谐振电源系统的选配、组合是比较关键的问题。介绍了使用组合可调电抗器解决长距离GIL升压的电源系统,分析了该系统的数学模型,提出了工频谐振下相对失谐度的概念,并对制约电压增益的因素进行了分析。提出使用二次压降测试仪进行误差校验,给出了重点参数的测量方法及试验步骤。最后,以澜沧江糯扎渡水电站GIL出线互感器误差现场检测试验为例,进一步验证了该方法解决长距离GIL中电磁式电压互感器误差校验的可行性和有效性。 相似文献
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GIS设备串联谐振耐压试验在现场的应用 总被引:1,自引:0,他引:1
SF6金属全封闭组合电器(GIS)是变电站的主要设备,检验GIS设备的制造质量和现场安装质量对确保电网安全可靠运行有重要意义,介绍了芜湖供电公司应用串联谐振装置对吉和变电站110 kV GIS设备进行安装后的现场耐压试验的实践过程,分析和讨论了试验注意事项、容升现象和结束判断,可供同类现场试验参考。 相似文献