摘要
目前随着变压器容量的增大,大部分变压器采用增加流速的方式来加快散热,但是流速的增大对油纸绝缘局部放电也会造成一定影响。为此,本文搭建了油纸绝缘系统的局部放电实验平台,研究流速对油纸绝缘局部放电特性的影响机制。研究结果表明,通过对油流静止下的放电图谱和实验现象分析,将油纸绝缘局部放电的过程划分为5个阶段:起始、缓慢发展、过渡、快速发展和预击穿阶段,并发现从过渡阶段到快速发展阶段存在一个转折电压,标志局部放电发展到绝缘纸板内部。在此基础上开展了不同流速下的局部放电试验,发现油纸绝缘局部放电参数随油流速度呈先减小后增大的趋势,在放电初期,不同流速间对于放电的影响较小,随着放电发展阶段的增加,流速间放电的差异逐渐明显。通过分析发现,电场强度和流速之间存在弱耦合关系,油纸绝缘局部放电水平的提升是电场强度和流速共同作用的结果,其结果导致放电后期的放电参数较前期更易受流速的影响。
At present with the increase of transformer capacity, most transformers speed up heat dissipation by in- creasing the oil flow rate, but which will also have a certain impact on partial discharge of oil-paper insulation. To study the influence mechanism of flow rate on partial discharge characteristics of oil-paper insulation, a partial dis- charge experimental platform is set up. The results show that the process of partial discharge of oil-paper insulation can be divided into five stages: initial phase, slow development, transition, rapid development, and pre-breakdown stage through the analysis of discharge patterns and experimental phenomena of static oil flow. From the stagnation stage to the rapid development stage, there is a turning voltage, which indicates that the partial discharge develops into the interior of the insulation board. On this basis, partial discharge tests at different flow rates are carried out, and it is found that the partial discharge parameters of oil-paper insulation first decrease and then go up with the in- creasing oil flow rate. In the early stage of discharge, the influence of different flow rates on the discharge is slight. With the progress of the discharge development stage, the difference between the flow rates is gradually obvious. By analyzing, there is a weak coupling between the electric field intensity and flow rate, which is the reason of the in- crease of the partial discharge level. Besides, the discharge parameters at the later stage are more affected by the flow rate than the previous period.
作者
粟茂
李春茂
夏国强
吴晋媛
高波
杨雁
SU Mao;LI Chun-mao;XIA Guo-qiang;WU Jin-yuan;GAO Bo;YANG Yan(School of Electrical Engineering, Southwest Jiaotong University, Chengdu 611756, China;Nanjing Nanrui Jibao Electric Co. , Ltd. , Nanjing 211106, China)
出处
《电工电能新技术》
CSCD
北大核心
2019年第7期47-55,共9页
Advanced Technology of Electrical Engineering and Energy
关键词
油流速度
油纸绝缘
油流带电
转折电压
外施电场
oil flow rate
oil-paper insulation
oil flow charged
turning voltage
applied electric field
