HVDC电缆终端电场分布特性及试验终端的设计

发布时间：2018-03-30 02:02

本文选题：高压直流电缆　切入点：电缆终端　出处：《哈尔滨理工大学》2017年硕士论文

【摘要】：高压直流输电在长距离、大容量输电方面具有明显优势,是实现我国“西电东送,南北互供,全国联网”的电力资源优化配置目标的优良技术手段。在引起电力电缆系统故障的诸多因素中,电缆终端作为电力电缆系统的基本结构出现故障所占的比例最大。当对电缆终端施加直流叠加冲击电压时,本体绝缘与增强绝缘界面处易于聚集空间电荷,导致局部电场发生畸变,严重时会使绝缘发生击穿,在一定程度上限制了直流电缆系统的发展。在直流电缆出厂前要对其进行不同试验的检测,如果试验时使用不合适的终端很容易造成错误的结果,在以往的试验中通常采用商品终端进行检测,然而其不可反复使用,造价高,因而需要一类性能可靠、安装方便、经济实用的试验终端对直流电缆进行检测。综上所述,研制合理的直流电缆终端和试验终端具有重要的现实意义。利用COMSOL Multiphysics仿真软件计算了以不同硅橡胶为增强绝缘,不同XLPE绝缘为电缆本体绝缘时电缆终端内的电场分布,选择出最优增强绝缘和本体绝缘组合,发现以普通硅橡胶作为增强绝缘,SiO2/XLPE复合绝缘作为电缆本体绝缘时,电缆终端内的电场分布较合理,并计算了其在稳态电场和暂态电场下的电场分布。其结果表明在负荷循环试验电压、雷电冲击电压、操作过电压作用下电缆终端内的电场分布合理。继而,对该电缆终端进行负荷循环试验以及冲击电压试验,试验过程中电缆终端未出现击穿以及闪络现象,表明该种绝缘配合的电缆终端具有优异的长期可靠性,满足使用要求。设计了均压环型、充油型、应力锥型HVDC电缆试验终端,并以此分别建立仿真模型,利用COMSOL Multiphysics软件计算了稳态电场和暂态电场下HVDC电缆试验终端内的电场分布,仿真结果表明:试验终端可明显改善电缆外屏蔽端部的电场分布,试验终端内和电缆端部的电场分布合理。
[Abstract]:HVDC transmission has obvious advantages in long distance and large capacity transmission. It is to realize the "power transmission from west to east, and from north to south to supply each other" in our country. Excellent technical means for the goal of optimizing the allocation of power resources based on national interconnection. Among the many factors causing power cable system failures, As the basic structure of power cable system, cable terminal has the largest proportion of faults. When the DC superimposed impulse voltage is applied to the cable terminal, the space charge is easily accumulated at the interface of body insulation and reinforced insulation. The local electric field will be distorted and the insulation will break down seriously, which limits the development of DC cable system to a certain extent. Different tests should be carried out before the DC cable leaves the factory. If the use of an inappropriate terminal in the test is likely to lead to wrong results, the commodity terminal is usually used for testing in previous tests, but it is not reusable and costly, so it requires a class of reliable performance and easy installation. The economical and practical test terminal detects DC cable. In conclusion, it is of great practical significance to develop a reasonable DC cable terminal and test terminal. Using COMSOL Multiphysics simulation software, the insulation of different silicone rubber is calculated. When different XLPE insulation is the electric field distribution in the cable terminal, the optimum combination of enhanced insulation and bulk insulation is selected. It is found that when the ordinary silicone rubber is used as the reinforced insulation, SiO2 / XLPE composite insulation is used as the cable body insulation. The electric field distribution in the terminal of the cable is reasonable, and the electric field distribution under the steady and transient electric field is calculated. The results show that the electric field distribution in the load cycle test voltage, the lightning impulse voltage, The electric field distribution in the cable terminal is reasonable under the action of operating overvoltage. Then, the load cycle test and impulse voltage test are carried out on the cable terminal. During the test, no breakdown or flashover occurs at the cable terminal. It is shown that this kind of cable terminal with insulation coordination has excellent long-term reliability and meets the requirements of application. The test terminals of HVDC cable with uniform voltage ring type, oil-filled type and stress cone type are designed, and the simulation models are established respectively. The electric field distribution in the test terminal of HVDC cable under steady and transient electric field is calculated by using COMSOL Multiphysics software. The simulation results show that the electric field distribution in the outside shield end of the cable can be improved obviously by the test terminal. The distribution of electric field in the test terminal and at the end of the cable is reasonable.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM75

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