共查询到20条相似文献,搜索用时 140 毫秒
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针对500kV罗洞变电站同时受天广、贵广、云广、江城、兴安等直流输电系统的影响,主变压器中性点直流问题相对突出,为确保罗洞站主变压器的安全运行,减少损耗,提出了在主变压器中性点回路串接电容隔直装置,用于隔绝大地系统中直流电流分量对主变压器的影响,并介绍该装置的构成原理和功能. 相似文献
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特变电工衡阳变压器有限公司近两年来,坚持以市场为导向,用现代经营理念,推动企业的快速发展。仅用两年时间取得了中国输变电行业中令人瞩目的骄人成绩。公司自行研制的我国第一台500kV自然油循环变压器,通过国家鉴定,其产品技术性能达到国内先进水平;公司自行设计、制造的220kV级10型三绕组有载调压12万kVA特大型变压器通过 相似文献
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运用变压器油色谱分析方法,成功地诊断出一台6 kV/0.4 kV油变因铁心接地联片绝缘烧损引起的中温发热伴随固体绝缘故障,从而有效提高了电力变压器故障检修效率,并采取有效措施排除变压器故障。 相似文献
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介绍了《南方电网500kV变压器保护及并联电抗器保护技术规范》出台后,大朝山水电站500kV联络变压器保护改造中采用PCS-978NC型变压器保护的选型、设计、安装、调试过程。云南电网内首次应用此型号变压器保护,通过改造,水电站变压器保护性能得到整体提升,对其他电站设计选型具有参考意义。 相似文献
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S. V. Korotkov Yu. V. Aristov A. L. Zhmodikov A. K. Kozlov D. A. Korotkov 《Instruments and Experimental Techniques》2018,61(1):38-43
The results of comparative investigations of assemblies of series-connected IGBT transistors (IRGPS60B120KD) with control circuits that are based on pulse transformers and ADuM21N microcircuits, which have a high insulation strength, are presented. The conditions for efficient switching of high-power current pulses with a submicrosecond rise time are determined. A small switch with an operating voltage of 12 kV that consists of two parallel-connected transistor assemblies is described. It provides switching of microsecond current pulses with an amplitude of 500 A and a rise time of 200 ns at a frequency of 100 Hz under natural cooling. The possibility of scaling the results is shown. 相似文献
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A device intended for testing the electric strength (ES) of insulating oil in electrical-engineering (electrophysical) equipment
is described. The probe is a system of many identical electrode elements mounted with alternate polarities with a gap of 0.5
cm between them, so that all elements with the same polarity are connected in parallel. The total area of elements of the
same polarity is >7000 cm2. Before measurements of the ES, the experimental relationship between the current through an oil layer between electrodes
and the liquid-breakdown voltage, which changed from 15 to 90 kV, was preliminarily determined at a potential difference U = 500 V between electrodes. Subsequently, the change in the current through oil at U = 500 V allowed evaluation of the breakdown voltage from the calibration curve. The promptness (several seconds) of remote
ES measurements with the possibility of automating them according to a chosen program has been confirmed. 相似文献
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智能变电站数字化保护是将变电站信息采集、传输、处理、输出过程全部数字化,通过分层、分布式通信网络传输,实现全站信息共享。由于超高压变电站动态电磁环境、温度等因素影响,采集电路易受干扰,严重影响采样过程和数据同步。解决这一难题,需要一次设备智能化,二次设备网络化,通过直接采样或网络采样方式,将电子式互感器、合并单元、智能终端、对时技术等有机结合,提高采样精度和信号传输的可靠性。 相似文献
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For better performances, electronic instrument transformers are used to replace conventional electro-magnetic inductive current or potential transformers based on ferrous cores and windings to measure heavy current and high voltage in power system. But unpredictable stability, high price and unsatisfactory life hold back their industrializations. Employing the simple but reliable insulation structure of conventional transformer and the unconventional sensing methods of electronic transformers at the same time, an innovative combined electronic instrument transformer is presented in this paper. Performances of the prototype are estimated through relative tests, and the novel design has low price, high accuracy, satisfactory stability, very wide frequency response and long operation life, and therefore is well adapted to any voltage level up to 750 kV. 相似文献
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唐开勇 《现代制造技术与装备》2006,(6):68-70,79
机床液压系统中油温过高会严重地影响液压机构工作的灵敏性、准确性和稳定性,影响机床的加工精度;系统设计不合理、容积损耗、机械摩擦和油液选用不当是造成液压系统油温升高的主要因素;合理地设计液压系统、防止泄漏以减少容积损耗、提高零件的加工精度和改进设备安装质量以减少机械摩擦、选用合适的油液等是防止油温过高的基本措施。 相似文献
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稳定溴同位素可用来识别和评价地下水的来源、成因及其形成的水文地球化学与物理过程。由于热电离质谱仪Triton的加速电压是固定10 kV不可调节的,因此,其最大的测定质量数为310 u。为了测定质量数更高的Cs2Br+(m/z 345,347)离子,本研究通过对热电离质谱仪Triton加速电压单元的改造,成功地将加速电压由10 kV降低到8 kV,使可测定的离子质量数从310 u扩展到350 u。在此基础上,建立了在8 kV加速电压下相应的质量校正曲线,进行了基于133Cs279Br+(m/z 345)和133Cs281Br+(m/z 347)离子的稳定溴同位素静态多接收测量。结果表明:当溴含量低于10 μg时,测定结果偏低;当溴含量高于10 μg时,测定结果正常。该方法测定溴同位素具有涂样量少(10~20 μg Br),测定外精度高(0.09‰~0.18‰)和采集数据时间短(8 min可采集100 个数据)等优点,可为地质样品中溴同位素地球化学的研究提供参考。 相似文献