摘要
为研究Nomex绝缘气隙缺陷的局部放电特性,首先从理论上探讨了Nomex绝缘中气隙的电场强度及起始放电电压与气隙类型及其尺寸的关系,然后在COMSOL Multiphysics中对气隙放电发生前后的Nomex绝缘和气隙的电场分布和空间电荷分布进行了仿真,并制作了含有气隙缺陷的Nomex绝缘气隙放电模型,在恒压条件下对气隙放电模型进行了连续的局部放电测试,揭示了气隙放电过程中相关局部放电统计特征参量的发展规律,最后对气隙放电机理进行了分析。结果发现Nomex绝缘中气隙的电场强度与起始放电电压和气隙类型及其尺寸有关,气隙放电与气隙中的电场分布和空间电荷分布有着密切关系。此外,研究表明累积放电量和每秒平均放电量的变化较为稳定,是表征长时间放电对Nomex绝缘介质损伤累积过程和气隙放电发展特性相对较好的指标。这一研究结果为干式变压器Nomex绝缘缺陷类型识别及绝缘寿命评估提供了理论依据。
In order to investigate the characteristics of the partial discharge(PD) defects on the Nomex paper used for mining dry-type transformer insulation with cavity, we theoretically analyzed the relationship between the electric field strength or partial discharge inception voltage of Nomex insulation and the type and dimension of cavity. The electric field and space charge distribution of cavity within Nomex insulation were simulated before and after partial discharge occurred in COMSOL Multiphysics. Then the model with artificial cavity in Nomex insulation was prepared. Based on this model, continuous tests using the constant voltage method were developed. The partial discharge characteristics were measured in the laboratory. Finally, the cavity discharge mechanism was analyzed. The results reveal that the electric field strength distribution of cavity in the Nomex, as well as the inception voltage of partial discharge, depends on the type and dimension of cavity. Moreover, partial discharge in the cavity is closely related to the distribution of both the electric field and the space charge. In addition, It is also concluded that the accumulative total discharge and average discharge energy per second in a stable trend and followed consistent rules are best indicators that are able to characterize the severity of the defects. This results has been applied to the pattern recognition and insulation life assessment of insulation for a 10 kV dry-type transformer in a coal mine and it has great application significance.
作者
宋建成
朱晶晶
田慕琴
张莎
温敏敏
SONG Jiancheng;ZHU Jingjing;TIAN Muqin;ZHANG Sha;WEN Minmin(Shanxi Key Laboratory of Mining Electrical Equipment and Intelligent Control,Taiyuan University of Teehnology,Taiyuan 030024,China;State Grid Xinzhou Power Supply Company,Xinzhou 034000,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2018年第12期4071-4082,共12页
High Voltage Engineering
基金
国家自然科学基金(51577123
51377113)
山西省科技厅重大专项(20131101029)~~
