三元混合绝缘油热裂解过程与产气特性  

Microscopic Mechanism of Thermal Cracking and Gas Production Characteristics of Three-element Mixed Insulation Oil

作　　者：徐晴 郝建[1] 叶文郁 高晨煜 张静文 廖瑞金[1] XU Qing;HAO Jian;YE Wenyu;GAO Chenyu;ZHANG Jingwen;LIAO Ruijin(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400044

出　　处：《高电压技术》2023年第3期1026-1037,共12页High Voltage Engineering

基　　金：国家自然科学基金(52077015);国家自然科学基金创新研究群体项目(51321063);国家“111”计划(BP0820005)。

摘　　要：从绝缘油物质成分原子水平研究揭示绝缘油的热裂解产气机制,是科学指导基于油中溶解气体实现变压器故障诊断的关键。基于反应分子动力学对三元混合绝缘油中不同物质成分的单分子、多分子和混合油体系的热裂解动力学过程进行仿真模拟,研究分析了矿物油、天然酯和改性天然酯中不同类型油品分子的热裂解路径及产气行为,以及三元混合绝缘油的热裂解产气特性,并通过油品过热产气试验验证了仿真结果。结果表明:矿物油、天然酯和改性天然酯分子在热应力下会通过解环、脱羧与脱羰等反应转化为链状烃,再逐步裂解为烃类气体小分子;当油品分子体系增大时,分子热裂解方式与油品单分子相同,但其热裂解反应进程会加快。三元混合绝缘油热裂解仿真结果表明,其在低温过热时油中CO_(2)含量最高,中温过热时油中H_(2)和烃类气体含量增加,高温过热时油中C_(2)H_(2)含量增加,C_(2)H_(4)、C_(2)H_(6)含量增加显著,该油品过热产气试验结果与仿真结果一致。该成果可为基于油中特征气体分析实现三元混合绝缘油变压器过热故障诊断提供理论指导。To guide the transformer fault diagnosis based on dissolved gas analysis(DGA),it is necessary to study the thermal cracking mechanism and gas behavior of mixed oil at the atomic level.Based on ReaxFF molecular dynamics(MD),we built models of single molecule,multi-molecule,and three-element mixed insulation oil,and simulated the thermal cracking kinetics process of these models.Moreover,we studied the thermal cracking paths and gas behavior of different types of molecules in mineral oil,natural ester,and modified natural ester,as well as the gas production characteristics of mixed insulation oil.Then,the simulation results were verified by overheating fault tests.The results show that the oil molecules are transformed into chain hydrocarbons through the reactions of decycling,decarboxylation,and decarbonylation under thermal stress,and then gradually cleaved into small hydrocarbon gas molecules.The increase of molecule number in the system does not affect the thermal cracking paths,but it will accelerate the cracking process.The simulation results of thermal cracking of three-element mixed insulation oil indicate that CO_(2) content in the oil is the highest when low-temperature overheating faults happen.H_(2) and hydrocarbon gas contents increase when medium-temperature overheating faults happen.When high-temperature overheating fault happen,the C_(2)H_(2) content increases,and C_(2)H_(4),and C_(2)H_(6) contents increase significantly.At last,the test results of gas behavior in mixed insulation oil are consistent with the simulation results.This paper provides theoretical guidance for the implementation of the three-element mixed insulation oil transformer overheating fault diagnosis based on DGA.

关 键 词：混合绝缘油 热裂解 反应分子动力学 反应路径 产气特性 

分 类 号：TM215.4[一般工业技术—材料科学与工程] TM411[电气工程—电工理论与新技术]