摘要
为了掌握电缆铝护套至导体热阻随温度变化的规律,提出了电缆铝护套至导体热阻的模型,通过高压单芯电缆阶跃电流温升实验,得到电缆各层在不同稳态下的温度分布,并根据热阻定义,推导电缆各层在不同温度下的热阻值及其随温度变化的规律。结果表明:电缆铝护套至导体热阻随温度的升高而降低,递减速率随温度的升高而变缓,并趋于稳定;单位长度电缆的绝缘层热阻和铝护套至导体热阻分别趋近于0.50 K.m/W和0.55K.m/W,其值比IEC 60287标准计算值分别小0.054 7K.m/W和0.077 1K.m/W;求得铝护套至导体热阻率为3.070K.m/W,比标准值小0.43K.m/W;气隙层热阻值为空气强制对流热阻值和接触热阻值并联之和,其值比标准值小1个数量级。
To obtain the law of thermal resistance between aluminum sheath and conductor of cable（Ts-c） varying with temperature,we proposed and experimentally studied a model of Ts-c.Temperature distribution of cable layers in different steady states was obtained in step current temperature experiments on high-voltage single-core cable.Then,the thermal resistance of cable layers at different temperatures and their varying principles with temperature were deduced based on the definition of thermal resistance.The results show that Ts-c decreases with increasing temperature,at a rate that also decreases with increasing temperature,and tends to be steady at last.The thermal resistance of the insulation layer and Ts-c become to 0.50 K · m/W and 0.55 K · m/W,respectively,which are 0.054 7 K · m/W and 0.077 1 K · m/W less than their calculated values according to Standard IEC 60287,respectively.The experimental value of thermal resistivity between aluminum sheath and conductor is 3.070 K · m/W,0.43 K · m/W less than its standard value.The thermal resistance of air-gap layer is sum of air resistance and contact resistance,of which the order of magnitude is less than its standard value.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2013年第3期712-718,共7页
High Voltage Engineering
基金
国家重点基础研究发展计划(973计划)(2009CB7-24507)~~
关键词
高压单芯电缆
热阻模型
热阻率
材料热阻
接触热阻
动态特性
high-voltage single-core cable
thermal resistance model
thermal resistivity
material thermal resistance
thermal contact resistance
dynamic characteristic
