单芯电力电缆交流电阻以及复合屏蔽层涡流损耗的计算

发布时间：2018-03-20 09:20

本文选题：单芯电缆　切入点：交流电阻　出处：《华南理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：与架空输电线路相比，电力电缆因具有美观和更高的可靠性而广泛用在城市配电网中。随着城市对电力需求的增加，对电力电缆载流量的要求越来越高。而电缆线芯结构以及电缆护套结构对电缆载流量影响很大。IEC-60287中有实心导体交流电阻以及护套损耗的公式，但是在其它结构和条件下没有相关公式和评估方法。本文研究了单芯电力电缆不分割导体与分割导体交流电阻的计算以及电缆复合屏蔽层涡流损耗的计算。对不分割导体，本文通过参考摩尔根关于架空输电线路钢芯铝绞线的分析方法并经过一定的修正来分析电缆绞线的磁特性，将每层绞线中的电流产生的磁通分为纵向磁通与环形磁通，根据电路理论建立计算电缆交流电阻的电压方程，方程中考虑了绞线绞向以及节距等参数的影响。计算结果表明，各层异向绞合电缆的交流电阻比各层同向绞合电缆的要大几个百分点；节距越大，交流电阻越小。不同绞向方式计算结果的差别虽然不大，但是在大规模工业应用中，较小的交流电阻将节省大量的铜，因此可以作为电缆结构优化设计的参考。对分割导体，本文研究了CIGRE工作组的方法，将每个分割的损耗分为两部分，一部分为分割本身的作用，另一部分为其它分割的作用。文中特别考虑了实心导体电缆与绝缘绞线电缆的情况，对实心导体的仿真计算指出了理论的适用性；分析了分割导体使用绝缘绞线降低交流电阻的基本原理，并将交流电阻的理论计算值与已有的历史数据作对比，验证理论正确性。复合屏蔽层由屏蔽层导线和防水用的金属箔层组成，IEC-60287中有金属箔层涡流损耗的计算公式，但是没有屏蔽层导线涡流损耗的计算公式。本文使用数值仿真软件计算屏蔽层导线内部涡流损耗以及屏蔽层导线在两端分别接合且至少有一端不接地时的线间环流损耗，并与CIGRE工作组的模型计算结果作对比，，验证其模型的正确性。计算结果表明，屏蔽层导线的涡流损耗远小于同截面积的电缆护套。若屏蔽层导线是直导线，则导线之间的环流损耗与相同截面积的电缆护套涡流损耗相同；若屏蔽层导线是绝缘绞合导线，则这些导线之间将没有环流产生，也即没有环流损耗。
[Abstract]:Compared with overhead transmission lines, power cables are widely used in urban distribution networks because of their beautiful appearance and higher reliability. The cable core structure and cable sheath structure have a great influence on the cable carrier current. IEC-60287 has the formula of solid conductor AC resistance and sheath loss. However, there are no relative formulas and evaluation methods under other structures and conditions. In this paper, the calculation of AC resistance of unsplit conductor and split conductor of single core power cable and the calculation of eddy current loss of composite shield layer of cable are studied. For undivided conductors, the magnetic properties of cable strands are analyzed by referring to Morgen's analysis method of steel core aluminum strands of overhead transmission lines and with some modifications. The flux produced by the current in each layer of strands is divided into longitudinal flux and annular flux. According to the circuit theory, the voltage equation is established to calculate the AC resistance of the cable. The influence of the tangential direction and pitch of the cable is considered in the equation. The calculation results show that, The AC resistance of each layer is several percentage points larger than that of the same layer of twisted cable. The larger the pitch, the smaller the AC resistance. Small AC resistance will save a lot of copper, so it can be used as a reference for cable structure optimization design. For the partitioned conductor, this paper studies the method of CIGRE working group. The loss of each partition is divided into two parts, one is the function of the segmentation itself. The other part is the function of other partitioning. In this paper, the case of solid conductor cable and insulated strand cable is specially considered, and the theoretical applicability of the simulation calculation of solid conductor is pointed out. The basic principle of using insulated strand to reduce AC resistance is analyzed, and the theoretical calculation value of AC resistance is compared with existing historical data to verify the correctness of the theory. The composite shielding layer consists of a shield wire and a waterproof metal foil layer. The calculation formula for eddy current loss of the metal foil layer in IEC-60287 is obtained. But there is no formula for the eddy current loss of the shielded conductor. In this paper, the eddy current loss inside the shield conductor and the inter-line circulation loss of the shielded wire joining at both ends and at least one end without grounding are calculated by using the numerical simulation software. The results are compared with those of the CIGRE working group to verify the correctness of the model. The calculation results show that the eddy current loss of the shielded wire is much smaller than that of the cable sheath with the same sectional area, if the shielded wire is a straight conductor, The circulation loss between the conductors is the same as the eddy current loss of the cable sheath with the same cross-sectional area; if the shielded conductor is an insulated twisted conductor, there will be no circulation between these conductors, that is, there will be no circulation loss.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM75

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