特高压直流避雷器电阻片加速老化试验方法的研究  

Method of Accelerated Ageing Test for ZnO Varistors in UHV DC Arresters

作　　者：赵霞 张搏宇 时卫东 沈海滨 贺子鸣 吕雪斌 ZHAO Xia;ZHANG Boyu;SHI Weidong;SHEN Haibin;HE Ziming;LV Xuebin(China Electric Power Research Institute,Beijing 100192,China)

机构地区：[1]中国电力科学研究院有限公司,北京100192

出　　处：《电瓷避雷器》2022年第2期93-97,共5页Insulators and Surge Arresters

基　　金：国网公司科技项目“特高压直流换流站避雷器保护水平优化研究”(编号:GYB17201700222)。

摘　　要：为满足特高压直流工程需求,避雷器用ZnO电阻片配方及工艺均得到较大调整,表现出与前期不同的老化特性。研究发现,随着老化时间增长,功耗曲线逐渐降低后趋于稳定。通过对比老化前后的两个电气参数(参考电压和冲击残压)后发现,电阻片正方向参考电压增大,反方向降低,严重时变化率可超过5%;正反向残压均增大。根据双Schottky势垒模型分析老化机理认为,非稳态离子锌填隙和晶界氧离子在直流电场下的定向迁移导致势垒畸变,荷电率越高畸变越严重,使得宏观电气性能出现上述变化。依据现行标准此类电阻片能够通过加速老化试验,但是电气参数的变化表明其保护性能降低。为此,本研究对直流ZnO电阻片的老化试验方法提出改进建议。As required by UHV DC project, manufacturers have improved the formulation and craft technology for ZnO varistors, after which their accelerated ageing performances have also changed. The measurement results manifests that as time goes by, the power loss during accelerated ageing test gradually decreases to an approximately steady value. After accelerated ageing test, the reference voltage in the positive direction increases while opposite in the negative direction, where the variation can even get up to 5%. Besides, the residual voltage under 8/20 μs pulse increase in both direction. Based on the double Schottky barrier model, it is deduced that metastable ions, such as zinc interstitial and oxygen ion, migrates under dc electric field, leading to deformation of barrier and changing above electrical parameters. Although the protective performance degrades, those varistors can still pass the test according to present standard. Therefore, some suggestion is put forward for accelerated ageing test in this paper.

关 键 词：避雷器 ZNO电阻片 老化试验 

分 类 号：TM862[电气工程—高电压与绝缘技术]