基于局放和介损的10kV XLPE电缆绝缘诊断研究

发布时间：2018-03-19 23:07

本文选题：电力电缆　切入点：局部放电　出处：《华中科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着电力基础建设的迅猛发展，，城市配网的不断扩大，XLPE电力电缆在城市配网中低压等级中占据越来越重要的地位，一旦电缆线路发生故障，将造成无法预计的停电损失。如何对10kVXLPE电缆绝缘“健康状况”进行优化诊断，对于及时掌握设备运行状况，制定正确检修策略，减少电缆线路非正常停电事故的发生，确保其运行可靠性意义十分显著。本文通过采用ANSYS对电缆附件复合界面受潮、外半导电断口台阶、主绝缘划伤等典型缺陷的静电场分布进行了计算，定量分析了不同缺陷的危害程度。基于对XLPE电缆的局放脉冲信号传播过程中幅值、频率以及脉宽的变化规律的仿真研究，重点建立了电缆接头复合界面不同程度受潮缺陷的等值电路模型，仿真提出了一种基于TDR法检测其受潮缺陷的方法及典型图谱。同时，通过建立计及松弛极化过程的XLPE电缆绝缘介质损耗数理模型，对不同长度、密度的多形态水树枝，以及电缆附件复合界面受潮等绝缘缺陷进行了数字仿真，提出了采用超低频介损诊断中压电缆绝缘劣化的方法与适用范围。在理论分析和仿真研究的基础上，采用高频局放带电检测、离线OWTS局放检测及定位、超低频介损测试以及基于脉冲信号的时域反射波法对XLPE电缆绝缘状态进行了现场实测，并对疑似缺陷电缆取样二次复测和解剖分析。提出了10kV XLPE电缆线路绝缘诊断综合方法的框架与实施流程，为工程实际应用提供参考依据。
[Abstract]:With the rapid development of power infrastructure, XLPE power cable plays a more and more important role in the low voltage grade of urban distribution network. How to optimize the diagnosis of 10kV XLPE cable insulation "health condition", to grasp the equipment running condition in time, to formulate the correct maintenance strategy, to reduce the cable line abnormal blackout accident, It is very significant to ensure its reliability. In this paper, the electrostatic field distribution of typical defects such as composite interface moisture, outer semi-conductive fracture step, main insulation scratch and so on are calculated by ANSYS. Based on the simulation study of amplitude, frequency and pulse width of partial discharge pulse signal of XLPE cable, the damage degree of different defects is analyzed quantitatively. The equivalent circuit model of different degrees of dampness defects at the composite interface of cable joints is established. A method and typical map of detecting the dampened defects based on TDR method are proposed by simulation. At the same time, by establishing the mathematical model of dielectric loss of XLPE cable considering the process of relaxation polarization, the insulation defects such as different length and density of multi-form water tree, and the composite interface of cable accessories are simulated. The method and application range of medium voltage cable insulation deterioration by using ultra low frequency dielectric loss are put forward. On the basis of theoretical analysis and simulation study, the insulation state of XLPE cable is measured by high frequency PD live detection, off-line OWTS PD detection and location, ultra-low frequency dielectric loss test and time-domain reflection method based on pulse signal. The frame and implementation flow of the comprehensive method for insulation diagnosis of 10 kV XLPE cable line are put forward, which provides a reference for practical application.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM855

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