共查询到18条相似文献,搜索用时 109 毫秒
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介绍电缆常用的试验方法,指出了交联聚乙烯(XLPE)电缆试验存在的主要问题,提出了0.1Hz超低频(SLF)耐压试验方法,给出了0.1Hz超低频(SLF)耐压试验的标准和规范。 相似文献
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为了研究高温超导电缆在直流和交流载流情况下伏安特性的变化规律,提出基于第二代YBCO高温超导体的冷绝缘超导电缆交直流伏安特性测试方法,搭建了伏安特性测试实验系统,通过对一根0.2m长,110k V/1.5k A高温超导电缆样缆的交直流伏安特性进行测试,获得了超导电缆在直流、30Hz、100Hz和工频载流下伏安特性变化规律。结果表明,超导电缆的直流伏安特性曲线呈现E-J指数关系,且失超变化清楚,而交流下当超导电缆通流值低于直流临界值时,交流伏安特性曲线变化平缓,之后随通流能力增加后该曲线呈逐渐上升趋势,超导电缆没有出现明确的失超变化点。研究结果对于开展超导电缆运行稳定性研究提供了较大的参考价值。 相似文献
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50Hz和400Hz低压阻性小电流电弧对AgMeO触头电弧侵蚀的研究 总被引:2,自引:1,他引:1
利用电光分析天平、扫描电镜与能谱仪测量与分析了CAgCdO与AgSnO2In2O3触头材料在低压交流50Hz和400Hz、纯阻性、小电流通断试验的表面形貌与组份,探讨了50Hz和400Hz下AgMeO触头材料电弧侵蚀机理. 相似文献
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分析了工频电压、0.1 Hz超低频电压、串联谐振条件下现场测量XLPE电缆tanδ的适用性及优缺点。对比发现,工频电压下用电桥测量tanδ能准确反映XLPE电缆的绝缘状况,但电桥容量较小限制了其使用范围;0.1 Hz超低频电压下测量tanδ的方法得到了广泛研究和认同,但tanδ值不能表征XLPE电缆工频电压下的绝缘状况;串联谐振装置测量tanδ能基本反映XLPE电缆的绝缘状况,但配套设备体积制约了其应用。 相似文献
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F.M. GattaAuthor Vitae A. GeriAuthor VitaeS. LauriaAuthor Vitae M. MaccioniAuthor Vitae 《Electric Power Systems Research》2012,83(1):160-169
The paper deals with the operation of very long EHV AC cable lines in a well-developed bulk power system, by simulating two 400 kV-50 Hz single circuit cable lines, 80-100 km long, installed at different locations of the Italian transmission network, both standing alone and in parallel to an existing overhead line. The power transmission limits of the considered cable lines are assessed analytically, as well as the required amount of shunt compensation and its location, at line terminals or also at mid-line; a criterion for sizing mid-line shunt compensation is also proposed. In order to check theoretical analyses carried out by analytical formulas, AC load flow simulations of the transmission network with the hypothetical cable lines in place are evaluated, referring to severe loading conditions in both normal and post-contingency operation. Open-ended cable operation and shunt compensation contingencies are also addressed. Results show that power transmission limits due to cable ampacity and higher active power flows due to low cable reactance do not pose special constraints on the operation of the powerful network under examination. Appropriate shunt compensation minimizes the effects of surplus cable reactive power, allowing to operate long 400 kV-50 Hz cable lines (up to 100 km at least) with reactors at line terminals only. Moreover, if shunt compensation is installed also at mid-line, operating capabilities of the long cable lines are enhanced and losses reduced. 相似文献
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It is noted that the design of 415 Hz power systems for mainframe computer systems requires additional considerations beyond those of conventional 60 Hz systems. The effects of the higher frequency on the wiring, components, and power system design are explored. Voltage drop, line drop compensation, centralized versus distributed power sources, and the special requirements of typical mainframe computer systems are considered. The power quality requirements of 415 Hz computer systems are significantly different from those of 60 Hz computer systems. The steady-state voltage tolerance is generally much tighter while the frequency tolerance is much broader. Because of the effects of the higher frequency on wiring impedance, 415 Hz wiring practices are different from those for a 60 Hz system. Nonmetallic or nonferrous wireways and relatively short wiring runs are recommended. Wire sizes larger than #2/0 are not effective at reducing wiring voltage drop, parallel conductors in parallel conduits are recommended. For best results, multiconductor cable assemblies such as the seven-conductor 400 Hz cable are recommended. Both passive and active line drop compensation techniques are available to help offset wiring voltage drop. Centralized 415 Hz power sources offer the advantages of economies of scale and ease of redundancy, which having the disadvantages of complicated 415 Hz wiring system design, higher installation costs, lack of flexibility, and potential load interactions. Distributed 415 Hz power sources minimize 415 Hz wiring and make it easier to meet the computer system's power requirements 相似文献
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F.M. GattaAuthor Vitae A. GeriAuthor VitaeS. LauriaAuthor Vitae M. MaccioniAuthor Vitae 《Electric Power Systems Research》2011,81(7):1525-1533
In the present paper the authors investigate steady-state capabilities of very long EHVAC underground cable lines, without intermediate compensating stations, installed in meshed networks. Analytical formulas of cable length-loading relationship are presented to this purpose. The study shows that, in optimal operating conditions, most of the ampacity of such long underground cable lines can be exploited for active power transmission. Non-optimal operating envelopes are studied, showing the effect of terminal voltages and line losses on cable utilization and evidencing limited derating under realistic hypotheses. A parametric analysis of loading limits and possible voltage violations along the cable is shown; a simple criterion for optimal utilization of lossy cable lines is also proposed. Line-end shunt compensation requirements for integration of long EHVAC cable lines in transmission networks are then specified. Studies performed for both ideal and real cables and shunt reactors show that active power transmission of 100 km long, 400 kV-50 Hz underground cable lines can attain 90% of their thermal limit, without intermediate compensating stations. Excess reactive power and temporary overvoltages are effectively controlled by line-end compensation around 90%. 相似文献
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Eager G.S. Katz C. Fryszczyn B. Densley J. Bernstein B.S. 《Power Delivery, IEEE Transactions on》1997,12(2):565-570
This publication describes a laboratory test program conducted with the objective to develop a test that would replace the existing DC withstand test. The article describes the methodology used to establish the voltage duration and magnitude of VLF (0.1 Hz) high voltage field tests suitable for crosslinked polyethylene (XLPE) insulated power cable. The results show that the voltage breakdown of laboratory aged XLPE cable at 0.1 Hz is approximately equal to that at 60 Hz, that proof tests at 0.1 Hz cause very little damage to the cable, and that 0.1 Hz testing appears to be a satisfactory alternate to DC testing. Preliminary values are suggested for voltage magnitude and time duration of cable acceptance, maintenance and proof tests at 0.1 Hz for XLPE cable rated up to 35 kV. A program is underway to similarly evaluate samples of service-aged XLPE cable; as well as to demonstrate the use of the preliminary test values at typical utility installations 相似文献
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介绍一种额定电压66 kV抗水树XLPE绝缘轻型海底电缆的研制方法。通过对模型电缆进行工频电压和雷电冲击电压击穿性能测试,按照CIGRE TB 722:2018规范对研制样品进行500 Hz/3000 h、50 Hz/8750 h、50 Hz/17500 h 3种湿式绝缘质量鉴定试验,按照CIGRE TB 490:2012和CIGRE TB 623:2015规范对研制产品进行型式试验,试验结果完全满足设计规范要求。在未来的深远海、大功率海上风机互联阵列海缆选型中,66 kV抗水树XLPE绝缘轻型海底电缆可以完美替代35 kV XLPE绝缘海底电缆。 相似文献
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针对振弦传感器应用中受电缆长度影响的问题,设计利用嵌入CPU的PWM输出功能,产生扫频现地激励传感器振弦,振弦受激励后,谐振的频率在现地经过嵌入的信号调理电路,自动增益检波,精确地检测振弦的谐振频率,实现1个对偶配套的振弦传感器数字化、隔离化、网络化变送器.变送器完成测量频率与对应物理量变化的实时数字转换,并通过隔离RS485通信输出.经过在某金属结构稳定观测系统的应用,证明该变送器的性能达到了预期目标,是一种新型的对偶变送器. 相似文献
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2004年,丹麦电网3条挤压成形的400kV双回电缆正式带电运行.这3条双回电缆采用波纹管,用于从奥尔胡斯到奥尔堡的400kV输电线路(140km)长达14.7km的线段中.文章介绍了400kV电缆系统,电缆的布局和连接、过渡组件以及电缆的补偿;同时也介绍了电缆线路的维护经验,还讨论了电缆的载流量,并与架空输电线路的载流量进行了对比,并将温度分布感应和动态负荷计算应用于控制中心每日的计划、预测工作中;最后,将架空线路与地下电缆线路的成本进行了对比. 相似文献