温度对油、纸介电参数及复合电场分布的影响

Influence of Temperature on Dielectric Parameters of Oil & pressboard and the Electric Field Distribution of Oil-paper Insulation Under Compound Voltage

为研究极限运行温度（-40~100℃）内温度对换流变压器油纸复合绝缘电场分布的影响,在不同温度下对浸油纸板和变压器油的电阻率及相对介电常数进行了测试,并通过公式推导来研究复合电场下温度对油纸绝缘电场分布的影响.试验结果表明,温度对浸油纸板和变压器油相对介电常数的影响较小,且两者的比值随温度变化也较小;但温度对浸油纸板和变压器油电阻率的影响较大,虽然两者的电阻率总体上随温度的升高都呈下降趋势,但两者下降的速度不同,从而造成不同温度下两者电阻率比值的差异显著.由计算结果可知,温度对复合电压作用下油和纸电场分布有显著影响,油中的最大场强出现在高温和交流电压作用的条件下,而纸板中的最大场强出现在低温和直流电压作用的条件下.

In order to study the temperature influence on the electric field distribution of oil-paper insulation in converter transformer under compound electric field and extremely operating temperature（-40℃ to 100℃）,the experiment research was carried out to study the influence of temperature on the relative permittivity and resistivity of oil and oil-impregnated pressboard. Then,the characteristics of electric field distribution with temperature were analyzed under compound voltage by equation deduction. The experiment result shows that,temperature has little influence on the relative permittivity of oil and pressboard. But there are great influence on their resistivity and their ratio,because of the difference between their falling speeds. The calculation results show that the max electric strength in oil appears on the condition of high temperature and AC voltage,but there is an opposite trend in pressboard.