共查询到20条相似文献,搜索用时 15 毫秒
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采用MATLAB仿真的变电站高压进线温度场和载流量数值计算 总被引:1,自引:0,他引:1
随着电力电缆在输配电线路中的广泛应用,准确确定电力电缆及其周围环境温度场的分布和电缆的载流量对于提高电力电缆的使用率、动态调整负荷具有重要的意义。为此,以地下排管敷设的交联聚乙烯电力电缆为研究对象,其实际模型为1个容量为250MVA、额定电压为230kV的变电站的高压进线。根据传热学和有限元法(finite element method,FEM)基本原理,建立了1种基于有限元法的水泥排管敷设电缆温度场计算模型,并对电缆及其周围环境的求解区域进行复合有限三角形单元剖分,即对电缆区域进行较密集的网格划分,而对电缆周围的土壤区域则进行较为稀疏的网格划分,以提高程序的运算精度和运行速度。结果表明:用MATLAB软件仿真,从而得到电缆及其周围环境的温度场分布,迭代计算了排管敷设交联聚乙烯电缆的载流量。证明使用有限元的方法分析地下电缆温度场,为电力工程中电缆载流量确定提供了一个比较可靠的计算方法。 相似文献
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Bow K.E. Snow J.H. Voltz D.A. Wilkens W.D. 《Industry Applications, IEEE Transactions on》1993,29(3):631-638
Medium-voltage power cables for modern petrochemical plants are considered. Test requirements, both at the factory and in the field, are considered to ensure that high-quality cable is manufactured and installed without damage. Cable technology changes and specifications are discussed. A new approach using life-cycle costs, which is making inroads in the petrochemical industry is described. The supplier partnership process for obtaining quality cable is discussed. Economic factors for the selection of power cables are detailed. It is argued that implementation of these programs will increase product performance and reliability, resulting in the lowest evaluated total cost of cable system ownership 相似文献
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预制分支电缆在供配电系统中应用的讨论 总被引:1,自引:0,他引:1
本文介绍了预制分支电缆的优越性,但与封闭式母线槽相比,还存在着不少的局限性与不足,因此目前尚无法完全取代母线槽在供配电系统中的重要位置,需对预制分支电缆的产品结构不断改进,进一步降低产品成本,增加推广力度。 相似文献
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El-Kady M.A. Anders G.A. Motlis J. Horrocks D.J. 《Power Delivery, IEEE Transactions on》1988,3(4):1303-1309
The authors previously described a technique for calculating the geometric factor G b for extended ranges of the height/width ratio of the duct bank or backfill that enabled the Neher-McGrath method to be applied to a wider range of cable configurations. However, the technique was based on the assumption that the duct bank surface represents an isothermal boundary, which can result in some errors in the derived G b-values. A finite-element-based technique is described for calculating modified values of G b on the basis of the actual heat-transfer mechanism (constant total heat flux) around the duct bank surface. The technique was applied to several cable configurations, yielding more accurate values 相似文献
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交联聚乙烯电力电缆的介电损耗机理(英文) 总被引:1,自引:0,他引:1
基于电介质物理学经典理论及其在聚合物绝缘材料上的最新发展,阐述绝缘材料的介质损耗机理以及交联聚乙烯电力电缆介电损耗的最新研究进展。通过大量的试验研究,结合等效电路法和微观理论分析,发现了交联聚乙烯电力电缆绝缘系统中在不同频率时起主要作用的3种不同类型的介电损耗,且这些介电损耗共同造成了50 Hz频率电力电缆系统的介电损耗。这一新发现可以帮助电缆制造商提高生产技术,有助于电气工程师更好地了解电力电缆绝缘系统,从而可能减少电力电缆的介电损耗和增加其寿命。 相似文献
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针对电力工程电缆优化分割下料问题,建立了以电缆原材料总长最小为优化目标,采用Matlab与C#.net混合编程实现该优化的数学模型。在此基础上研制开发了基于B/S模式的电缆优化分割下料系统,包括自动生成可行下料方案、选定最优分割方案和计算原材料利用率等功能。最后通过实例分析与测试,表明该系统能够较好地实现电力电缆优化分割下料,也验证了Matlab和C#.net混合编程的特点和优势。 相似文献
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为实现航天器热试验外热流模拟装置与航天器之间绝缘性能的检测,对加热电缆绝缘自动测试技术进行研究,设计了一套基于PXI的航天器热试验加热电缆绝缘自动测试系统.该系统采用继电器矩阵技术设计了加热电缆输入通道切换装置,基于PXI总线仪器实现了多芯电缆自动扫描以及对地绝缘电阻的测量,并采用VC++ 6.0开发了系统上位软件.测试结果表明,该系统能够在短时间内完成最多8根加热电缆的对地绝缘检测,结果准确、运行可靠,大大提高了加热电缆绝缘电阻测试的自动化水平. 相似文献
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Two time-dependent heat transfer models were developed for calculating cyclic temperature-time profiles for underground power cables with any cyclic load. A fully distributed model allows for temperature variation with radial distance and time in each cable region. A lumped parameter model sets up a thermal circuit and solves for the temperature of each cable region as a function of time. Results from both models are compared with experimental temperature profiles for five cyclic tests for cables in a typical duct bank arrangement. The comparison shows good agreement for cable conductor and jacket temperatures and some error for conduit profiles. 相似文献
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RichardL Provost 《电力设备》2004,5(5):70-72
油浸式电力变压器采用混合绝缘系统,它是在变压器的热绕组区域中采用芳族聚酰胺绝缘,并在线圈外部较冷的区域采用了标准牛皮纸绝缘,这样可以在提高磁通密度的同时提高电流密度。章讨论了这些设计方式对绝缘系统包括固体绝缘和绝缘液体的影响,并且对绕组和油道进行了热分析。这种技术不仅提供较高的功率密度,而且还提高了整个绝缘系统包括液体绝缘的质量和寿命。另外,还评论了这种技术的应用实例,包括修理和更新老化或发生事故的变电站电力变压器。 相似文献
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新型高温潜热储能系统的性能研究 总被引:1,自引:0,他引:1
为了使采用直接蒸汽技术的太阳能热力发电达到商业化应用,须开发与之配套的高效、价低的高温潜热储能系统。提出了采用铝片强化高温潜热储能系统传热性能,并用fluent软件模拟了该系统在释能过程中的瞬态二维传热过程,得到了相界面位置、温度分布、液相率、热流随时间的变化关系,以及总凝固时间;对影响新型高温潜热储能系统性能参数如几何尺寸、边界条件、相变材料的导热系数等进行了研究,得到了这些参数与总凝固时间的关联式。计算结果表明,增加铝片能有效强化高温潜热储能系统传热性能;利用文中提出的关联式,可对新型高温潜热储能系统进行性能优化设计。 相似文献
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This paper presents a new approach to thermal field sensitivities and ampacity computations of underground power cables using a proposed algorithm of perturbed finite-element analysis. The new approach involves the use of derived sensitivity coefficients associated with various cable parameters of interest, and use these coefficients to achieve optimal cable performance. The proposed model provides a quick methodology, based on the finite-element model, to assess the cable thermal performance subject to variations in the cable thermal circuit parameters. The developed algorithm was applied to various practical cable systems. The effect of multilayered thermal conductivities and boundary parameters variations on the actual cable system ampacity was investigated using the proposed methodology. A comparison was made of the obtained results with the conventional finite-element approach in order to show the applicability and usefulness of the developed methodology. Our objective was to assess the effects of operating parameter variations in a straightforward manner, without repeating the thermal field analysis for each parameter change. The thermal field of an underground power cable sample directly buried in the soil was measured in the laboratory using a developed full-size experimental setup. The investigations involve all parts of the thermal circuit parameters representing cable composition, surrounding soil and boundary phenomena. The experimental setup was used to validate the simulation model by comparing the simulation results with the real laboratory measurements. Such experimental verification confirmed the accuracy of the new introduced finite-element sensitivity methodology. 相似文献
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考虑热进口段时管内对流换热过程的热力学分析 总被引:1,自引:0,他引:1
利用热力学第二定律,分别在壁面热流恒定和壁面温度恒定两种情况下,在考虑热进口段时对管内对流换热过程进行了热力学分析。引入了熵产强度和无因次熵产强度两个概念,并给出了有关计算式;讨论了壁面热流、壁面温度及流动阻力对无因次熵产强度的影响。本文的有关结果可为工程上换热器的优化设计提供理论依据 相似文献
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A time-dependent heat transfer model based on the complete Fourier integral was developed for calculating cable temperatures during short-term transient conditions. A cyclic heat transfer calculation is used to obtain the initial temperature-time profile of the cable before the transient loading begins. The short-term transient model uses a lumped parameter formulation for the different cable regions and the Fourier integral to approximate the transient heat loss profile. Calculated conductor, jacket, and conduit temperatures show reasonable agreement with experimental results for a number of short-term transient tests with cables in a typical duct bank arrangement. 相似文献
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为解决三芯电力电缆质量检验过程中内部各相芯线位置难以测定的问题,提出了一种测定三芯电力电缆内各相芯线位置的方法。具体地,通过在三芯电力电缆外表面轴向横截面对称地安装2个磁传感器,在给该电缆内某单相芯线施加电流激励后,用磁传感器测量所在位置处磁感应强度的切向分量;根据2个磁传感器的测得量值,利用安培环路定理以及该单相芯线中心位置与磁传感器位置之间的几何关系,求解该单相芯线中心到三芯电力电缆中心的距离,以及该单相芯线中心和三芯电力电缆中心的连线与y轴之间的夹角,即可求解出该单相芯线的位置;通过给三相芯线分别施加电流激励,便可分别测得三相芯线的位置,从而实现对三芯电力电缆内各相芯线位置的测定。电磁场有限元仿真试验和解析模型计算的结果表明,此方法准确性高,对三芯电力电缆生产工艺水平提高和质量检验具有指导价值。 相似文献