受潮对油浸式套管电热场的影响

Influence of Moisture on Electric and Thermal Field Distribution of Oil-immersed Bushing

套管受潮后水分在重力作用下积聚于套管尾部,为研究受潮对油浸式套管电场及温度场分布的影响,建立了110kV油纸绝缘套管的仿真模型,仿真了套管在不同受潮程度下套管内电场及温度场分布。结果表明:套管受潮后导致套管内电场强度和温度升高。受潮条件下套管内最大电场强度与套管尾部油浸纸受潮高度呈线性变化,且含水率越高,最大电场强度随油浸纸受潮高度的增大其增幅越大,但整体上受潮后套管内最大电场强度提升幅度并不显著;油浸纸中含水率质量分数低于4%时,套管内最高温度与套管尾端受潮高度呈线性变化,油浸纸中含水率为5%时,套管内最高温度与套管尾端受潮高度呈指数变化。受潮后套管内温升严重,是引发套管尾部放电致使套管损坏的主要原因。

With the action of gravity,moisture accumulates in the tail of the bushing when the bushing is damp.In order to study the influence of moisture on electric field and thermal field distribution of oil-immersed bushing,a simulation model of 110kV oil-immersed bushing was established,and the electric field and temperature field distribution of bushing under different damp conditions were obtained.The results show that the electric field intensity and temperature in the bushing increase when the bushing is damp.The maximum electric field strength increases linearly with wetting height of oil-impregnated paper,and the higher the moisture content is,the greater the increase of the maximum electric field intensity with the wetting height of oil-impregnated paper.On the whole,the maximum electric field strength isn't significantly increased after bushing wetted.When the moisture content in oil-immersed paper is less than 4%,the maximum temperature in the bushing changes linearly with wetting height of insulating paper;when the moisture content is 5%,the maximum temperature in the bushing increases exponentially with wetting height of oil-impregnated paper.The temperature rises seriously under damp conditions,which is the main reason for the discharge and damage of bushing.