油纸绝缘介质的空间电荷积聚与消散特性  

Space Charge Phenomena in Oil-Paper Insulation Materials Under High Voltage Direct Current

作　　者：王云杉[1] 周远翔[1] 李光范[2] 王宁华[2] 刘瑛岩[1] 孙清华[1] 李博[2] 李鹏[2] 程焕超[2] 

机构地区：[1]清华大学电机工程与应用电子技术系,电力系统及发电设备安全控制和仿真国家重点实验室,北京100084 [2]中国电力科学研究院,北京100085

出　　处：《高电压技术》2008年第5期873-877,共5页High Voltage Engineering

基　　金：教育部新世纪优秀人才支持计划(NCET-04-0095)~~

摘　　要：油纸材料的绝缘问题在换流变压器、直流套管、直流电缆等高压大型直流设备大量应用的情况下显得十分突出。为探讨高压直流设备绝缘的最主要问题—空间电荷效应,应用电声脉冲法(PEA)对油纸绝缘材料的空间电荷特性进行了研究。有关外加场强对油纸材料中空间电荷积聚情况的影响和在较高场强下油纸材料的击穿破坏与空间电荷关系的研究结果表明:①低场强下油纸材料中空间电荷以电离产生为主;而在较高场强下,先后在阴极和阳极产生了同极性载流子注入。②相对于聚乙烯而言,由于油纸材料的电导率较大,材料内的空间电荷在外加电场撤去后很快消散。③空间电荷的注入和运动会导致油纸材料的劣化和破坏。油纸材料中的空间电荷快速消散现象有利于直流设备在极性反转条件下的运行,为阐释油纸绝缘良好的长期性能提供了有重要意义的试验依据。This paper studied the space charge characteristics of oil-paper insulation materials by the Pulsed Electro- Acoustic （PEA） method. The effects of applied HVDC on space charge accumulation in oil paper was discussed. This paper also discusses the relationship between space charge and breakdown in oil paper. The result shows that the space charge comes from ionization at lower field stress. When the stress is higher, injection of homo carriers occurs at cathode first and anode later. The space charge inside oil-paper sample results in an electrical field distortion up to 40%. The oil-paper insulation material＇s conductivity is much larger compared with polyethylene, so the space charge dissipates fast when the applied field is removed. The experiment showed that most of the space charge in oil paper dissipated in 30 seconds after the source was removed, which is very different from other insulation materials such as low density polyethylene （LDPE）. The fast dissipation of space charge will play the key role in oil-paper material＇s insulating performance in condition of polarity reversal under HVDC. The injection and movement of space charge result in the degradation and breakdown of the oil-paper insulation material. When the applied electrical field rose to 50kV/mm-57kV/mm, the oil-paper material got breakdown in a short time. During this process, an obvious movement of space charge was observed.

关 键 词：空间电荷 油纸绝缘 PEA 场强畸变 劣化 极性反转 

分 类 号：TM21[一般工业技术—材料科学与工程]