摘要
交联聚乙烯绝缘层厚度设计是高压直流电缆研发的关键任务之一。然而,实验室中难以获得厚绝缘样品的直流击穿性能参数,绝缘层厚度设计缺少直接的数据支撑,因此研究交联聚乙烯绝缘直流击穿的厚度效应具有重要意义。该文获得了不同厚度交联聚乙烯绝缘样品在90℃下的直流击穿特性,揭示了交联聚乙烯绝缘威布尔特征击穿场强和形状参数随样品厚度的增加而减小的厚度效应。采用电荷输运和分子链位移调制模型计算了交联聚乙烯的直流击穿过程,结果表明击穿威布尔形状参数受陷阱能级、陷阱密度、载流子迁移率随机变量标准差的影响。在厚试样中,三种电荷陷阱参数的高斯分布更宽、标准差大,导致击穿场强分散性增大,其中电荷陷阱能级随机变量标准差的影响最显著。因此,交联聚乙烯绝缘电荷陷阱参数分布是决定其高温直流击穿厚度效应的关键。该研究可为高压电缆绝缘设计提供理论指导和实验依据。
The design of XLPE insulation thickness is one of the key tasks in the development and manufacturing of HVDC cables.However,it is difficult to obtain the DC breakdown performance parameters of thick insulation samples in the laboratory,and the design of insulation thickness lacks direct data support.Meanwhile,although there are continuous attention and researches on the thickness effect of breakdown field strength and the breakdown Weibull probability distribution of solid dielectric,there are few studies on the DC breakdown field thickness effect based on XLPE at high temperatures,and there are few reports on the dispersion of the DC breakdown field strength.Therefore,it is of great significance to study the effect of thickness on DC breakdown of XLPE insulation.In this paper,the high temperature DC breakdown experiment of XLPE insulation samples with different thicknesses was carried out,and charge transport and molecular displacement modulated model(CTMD)was used to simulate and analyze the breakdown process.Besides,the characteristic breakdown field strength and Weibull distribution shape parameters of XLPE insulation under high temperature DC voltage are studied with sample thickness.In dielectric insulation,the deep trap captures carriers,forming space charges at the interface of the insulating medium,and the continuous aggregation of space charges make the electric field strength distorted.At the same time,by the Coulomb force,the displacement of the molecular chains make the expansion of the free volume,the charge energy increases dramatically.When the charge energy increases to the point where it can leap over the trap barrier,the insulating material breaks down.DC breakdown experiments were carried out on 160,300,400,550 and 650μm XLPE specimens at 90℃.The characteristic DC Weibull breakdown field strengths were 264.1,212.6,185.0,147.7,136.4 kV/mm and the shape parameters of the Weibull distribution were 21.3,20.5,19.9,14.1 and 13.5.The process of carrier transport and energy accumulation in dielectr
作者
朱敏慧
闵道敏
林宋佳
王诗航
Zhu Minhui;Min Daomin;Lin Songjia;Wang Shihang(State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University,Xi’an 710049 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2024年第21期6908-6920,共13页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(52077162,51777162)
中央高校基本科研业务费专项资金(xzy012019022)资助项目。
