电工技术学报2025，Vol.40Issue(13)：4045-4057,13.DOI:10.19595/j.cnki.1000-6753.tces.240904
电热协同老化应力下环氧树脂复合材料沿面闪络特性与数值模拟
Characterization and Numerical Simulation of Epoxy Resin Composites Flashed along the Surface under Electro-Thermal Co-Aging Stresses
摘要
Abstract
Dry-type transformer is to high voltage level,high power density direction,long-term operation in the electro-thermal cooperative multi-stress complex working conditions such as epoxy resin casting insulation is more likely to induce along the surface flashover failure.In order to study the characteristics of epoxy resin along the surface flashover under the stress of electro-thermal cooperative aging,this paper builds a platform for flashover along the surface under AC stress,and it is found that when the aging temperature is 160 ℃,the flashover field strength of the epoxy resin specimen aged for 80 days is 2.11 kV/mm,which is a decrease of 25.7％.The steepest decrease in the field strength along the surface is found from 0 to 40 days,which is related to the rapid increase in the surface roughness of the specimen from 0 to 40 days. A plasma model of epoxy resin flashover along the surface is established by combining the continuity equation of charged particles,the average electron energy equation and the interfacial reaction characterization equation,and the dynamic simulation of flashover along the surface at the working frequency is realized.According to the results of the aging experiment,a random function is introduced to change the surface roughness of the medium,and the dielectric constant after aging is combined to simulate the accurate electro-thermal aging behavior of the epoxy resin,and the temporal and spatial evolution laws of the tangential electric field strength,electron density and surface charge density of the epoxy resin in the process of flashover before and after aging are obtained.The simulation results show that the electron density and surface charge density increase during the flashover development of the aging epoxy resin,and the electric field strength at the head of the flow injection reaches 1.183 kV/mm at 12 ns,an increase of nearly 10.87％.With the aging specimen due to the roughness and dielectric constant increase,its surface charge density will occur surge phenomenon,compared with the aging specimen before the increase of 57.66％,so that the electron density quickly reached the threshold value of the electron collapse to flow injection,resulting in the development of the flashover becomes faster. The mechanism of combined electro-thermal aging on the surface charge of epoxy resin specimens is explained by the trap effect,and the reason for the decrease in the flash field strength of the specimens is clarified.For the specimen aged for 80 days,the deep trap density and energy level increase to 2.56× 1016 eV-1·m-3 and 1.06 eV,respectively,resulting in an increase in the probability of charge entry trapping,which leads to a large amount of surface charge accumulation,and the electric field distortion becomes more serious,thus decreasing the flash-coincidence field strength along the surface.The above findings provide theoretical and methodological basis for the fault operation and maintenance and life prediction of dry-type transformers.关键词
环氧树脂/电热联合老化/沿面闪络/等离子体/表面陷阱Key words
Epoxy resin/electrothermal joint aging/flashover along the surface/plasma/surface traps分类
信息技术与安全科学引用本文复制引用
李思庚,李庆民,王伟,金虎,李锐海..电热协同老化应力下环氧树脂复合材料沿面闪络特性与数值模拟[J].电工技术学报,2025,40(13):4045-4057,13.基金项目
国家自然科学基金(52177147,52127812)、北京市自然科学基金(3232053)、国家重点研发计划(2021YFB2601404)和中央高校基本科研业务费专项资金(2023JC005)资助项目. （52177147,52127812）
