磁场环境下室温硫化硅橡胶电树枝生长特性  

Electrical Tree Growth Characteristics of RTV Silicone Rubber Under Magnetic Field

作　　者：杜伯学[1] 于洋[2] 殷震[3] 沈浮[3] 李进[1] 韩涛[1] 

机构地区：[1]天津大学电气与自动化工程学院,天津300072 [2]国网天津市电力公司电力科学研究院,天津300384 [3]国网天津市电力公司检修公司,天津300300

出　　处：《高电压技术》2017年第8期2702-2708,共7页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2014CB239506)~~

摘　　要：大电流产生强磁场,从而使电树枝生长过程中承受较大的电磁力。随着电力电缆载流量的不断增加,研究磁场环境下室温硫化(RTV)硅橡胶电树枝生长特性具有重要的理论意义和实用价值。为此,选用自制RTV硅橡胶试样,采用脉冲电源和交流电源对试样加压,分别模拟了试样在脉冲电场、交流电场与磁场的耦合场下的电树枝生长状况,研究了不同电压和磁场条件下的电树枝生长特性。结果表明:随着磁通密度的升高,在脉冲电压和交流电压下电树枝的起始电压会降低;脉冲电压下,电树枝长度会由于外界高磁场的存在而明显增加;交流电压下,磁通密度的升高会使电树枝类型发生变化,当磁通密度为400 m T时,所有电树枝呈丛林状,电树枝生长速度明显降低,400 m T时电树枝分形维数明显高于0 m T时的对应值。该研究结果为进一步研究磁场条件下硅橡胶中电树枝生长机理提供了参考。Electric field, accompanying with the magnetic field produced by high current, can generate eletro-magnetic force in power system, which enormously affects the electrical treeing process. Understanding electrical tree characteris- tics of room temperature vulcanized （RTV） silicone rubber under magnetic field is of great importance for wide application of high power DC cable. Therefore, with specimens made of RTV silicone rubber, repetitive pulse voltage and AC voltage supply, the effect of magnetic field on electrical tree characteristics with different voltage was investigated. Results show that, with the increase of the magnetic flux density, the electrical tree initiation voltage decreases under the pulse power supply and AC voltage supply. The length of electrical tree obviously increases due to the high magnetic field. Typical profiles of electrical tree change with the increase of magnetic flux density under AC voltage. When the magnetic flux reaches 400 mT, all electrical trees are bush tree, and the electrical tree growth rate obviously decreases, but the frac- tal dimension of the electrical tree at 400 mT is significantly higher than that at 0mT. This indicates that magnetic field improves the initial probability of electrical tree under both repetitive pulse voltage and AC high voltage supply. The growth of electrical trees becomes more dense with the increase of magnetic flux density. When the electrical tree grows to a certain degree, the promotion of magnetic field on the growth of electrical tree becomes weaken under AC voltage supply, while it is still strong under repetitive pulse voltage supply. The results provide a reference for further study on the growth mechanism of electric tree in silicone rubber under magnetic field.

关 键 词：硅橡胶 电树枝 磁场 脉冲电压 交流电压 分形维数 电力电缆 

分 类 号：TM215.2[一般工业技术—材料科学与工程]