配电变压器过载油纸绝缘老化特性研究

Studies on Aging Characteristics of Oil Paper Insulation System of Overloaded Distribution Transformer

配电变压器在运行过程中由于多种损耗导致发热严重,变压器内部绕组等部位的温度也随之升高,从而导致变压器内部绝缘材料逐渐老化。植物绝缘油由于其具有可再生性、生物降解性和较低的可燃性等优点,逐渐得到广泛应用,可代替矿物油作为变压器的绝缘介质。本文模拟了配电变压器过载情况,对多种类型的油品(矿物油、大豆油、菜籽油)、纸板(A级纸、B级纸)进行组合油纸绝缘系统热老化试验,模拟过载情况对配电变压器油纸绝缘系统的影响,得到不同老化温度下绝缘油老化特性(击穿电压、水分、酸值、介损等)与绝缘纸老化特性(含水量、聚合度、机械强度等)。

The distribution transformer will generate severe heat due to various types of losses during its operating,and the temperature of internal winding of transformer will be raising accordingly,leading to gradual aging of its internal insulation materials.As a substitution of mineral oil in transformer,vegetable insulating oil has been widely used because of its advantages of renewable,biodegradation and low flammability.In this paper,the overload condition of railway distribution transformer is simulated,and the thermal aging test of combined oil paper insulation system of various types of oil products(mineral oil,soybean oil,rapeseed oil)and paperboard(paper of grade A,paper of grade B)is carried out to simulate the influence of overload condition on oil paper insulation system of distribution transformer.The aging characteristics of insulating oil(breakdown voltage,moisture,acid value,dielectric loss,etc.)and insulating paper(moisture content,polymerization degree,mechanical strength,etc.)are obtained at different aging temperatures.