平行导线包覆绝缘护套工频击穿特性研究

发布时间：2018-06-28 17:33

本文选题：平行导线 + 绝缘护套　；参考：《武汉大学》2017年硕士论文

【摘要】：近年来,由于输电线路紧张,紧凑型输电技术得以广泛应用,且随着各种灾害性天气的逐渐增多,输电线路空气间隙击穿事故时常发生。空气间隙工频击穿事故是电网正常运行的重大安全隐患,且线路因空气间隙工频击穿跳闸后重合闸不易成功,严重影响了电力系统的安全稳定运行,因而造成重大的经济损失。目前国内对于高压输电线路空气间隙工频击穿的研究涵盖了风偏、覆冰、降雨、山火、浓雾等影响,涉及了杆塔、绝缘子串、导线及跳线的相关击穿理论、模型及试验,但鲜有采用新型导线绝缘涂料及护层防高压输电线路空气间隙工频击穿的相关技术。针对上述情况,本文提出了导线包覆绝缘护套以提升空气间隙工频击穿电压的研究思路,设计了平行导线包覆绝缘护套的试验模型,分别采用了不同绝缘护套和不同包覆方式进行了工频击穿试验,记录了导线包覆绝缘护套时工频击穿现象,对比分析了导线包覆绝缘护套对提升空气间隙工频击穿电压的效果。本文采用了四种不同的绝缘护套材料,为对这四种不同绝缘护套材料的电气特性进行探讨,分别对其进行了电气强度测试。为方便观察导线包覆绝缘护套后击穿电压的提升效果,本文先对裸导线进行了工频击穿试验,研究了裸导线工频击穿电压与导线间距的关系,试验结果表明,其电压随着导线线间最小距离的增大而近乎线性增大,且随着导线间距的不断增大,其平均击穿场强有所减小。本文通过裸导线包覆绝缘护套工频击穿试验,分别研究了单根导线包覆绝缘护套和双根导线包覆绝缘护套,以及导线涂覆绝缘涂料等情况,对线间绝缘特性的提升效果,并从安全距离角度对比分析了导线不同包覆方式对提升导线线间工频击穿电压的效果。本文利用COMSOL软件对短间隙距离情况下导线的工频击穿场强进行了仿真计算,并从场强角度分析了双根导线包覆绝缘护套对裸导线空气间隙击穿电压的提升原因。此外,还结合试验中的滑闪现象,根据导线包覆护套方式及结构,利用链形等值回路表示导线包覆绝缘护套模型,解释了平行导线包覆绝缘护层沿面滑闪原因。
[Abstract]:In recent years, because of the shortage of transmission lines, compact transmission technology has been widely used, and with the increasing of disastrous weather, the breakdown accidents of air gap in transmission lines often occur. The air gap power frequency breakdown accident is a major safety hazard in the normal operation of the power grid. Because of the air gap power frequency breakdown and tripping, the reclosing is not easy to succeed, which seriously affects the safe and stable operation of the power system, resulting in significant economic losses. The current domestic research on the power frequency breakdown of air gap in HV transmission lines covers the effects of wind deviation, icing, rainfall, hill fire, dense fog, and so on. It involves the relevant breakdown theory, model and test of pole tower, insulator string, conductor and jumper. However, there are few related technologies of new conductor insulation coating and protective layer against air gap breakdown of high voltage transmission lines. In view of the above situation, this paper puts forward the research idea of conductor coating insulation sheath to increase the power frequency breakdown voltage of air gap, and designs the test model of parallel conductor coating insulation sheath. The power frequency breakdown test was carried out by using different insulation sheaths and different coating methods respectively. The power frequency breakdown phenomenon of conductor coating insulation sheath was recorded, and the effect of wire coating insulation sheath on increasing the power frequency breakdown voltage of air gap was compared and analyzed. In this paper, four kinds of insulating and sheathed materials are used to study the electrical characteristics of these four kinds of insulating sheathing materials, and the electrical strength of these four kinds of insulating sheathing materials are tested respectively. In order to observe the improvement effect of breakdown voltage after the conductor is coated with insulation and sheath, this paper first carried out the power frequency breakdown test of bare wire, and studied the relationship between the power frequency breakdown voltage and the distance between the bare wire and the wire. The test results show that, The voltage increases linearly with the minimum distance between wires, and decreases with the increase of wire spacing. In this paper, through the power frequency breakdown test of bare wire coated insulation sheath, the effects of single wire coating insulation sheath and double wire coating insulation sheath, and wire coating insulation coating on the improvement of insulation characteristics between wires are studied, respectively. From the angle of safe distance, the effect of different coating methods on the power frequency breakdown voltage between hoisting wires is analyzed. In this paper, the power frequency breakdown field strength of conductors with short gap distance is simulated and calculated by COMSOL software, and the reason for lifting the breakdown voltage of air gap between bare conductors is analyzed from the point of view of field strength. In addition, according to the sheathing mode and structure of conductor coating, the model of conductor coating insulation sheath is represented by chain equivalent circuit, and the reason of parallel wire coating insulation sheath sliding along the surface is explained.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM75;TM21

【参考文献】