植物油-纸绝缘的电老化寿命试验研究

Study on Electrical Aging Lifetime of Vegetable Oil-paper Insulation

植物绝缘油具有高燃点和高闪点,几乎可完全生物降解以及良好的电气性能,是目前国际上重点研究的环保型液体绝缘材料。油纸绝缘结构因其稳定的性能而在电力设备中得到广泛的应用,因此评估植物油–纸绝缘的寿命具有重要意义。采用逐步升压法对植物油–纸绝缘模型进行加速电老化试验,利用双参数Weibull分布对试验数据作统计分析,反幂函数和指数函数拟合试验数据并求得电压耐受系数;同时进行矿物油–纸绝缘模型的加速电老化寿命试验,对比分析了2种油纸绝缘的加速老化性能。试验结果表明,由于植物绝缘油的介电常数比矿物绝缘油的高,使植物油–纸绝缘结构的电场分布比矿物油–纸绝缘结构的均匀,因此植物油-纸绝缘的电老化性能优于矿物油–纸绝缘。

As a new environmental friendly dielectric liquid, vegetable insulating oil has high fire point and flash point, almost fully biodegradable, excellent electric properties. Oil-paper structures are broadly used in electrical equipments because of its steady characteristics. For evaluating the lifetime of vegetable oil-paper model, the step-stress test is used in accelerated electrical stress aging test, and two parameter Weibull distribution is used to statistic analysis for the mean lifetime. This paper uses inverse power and exponential model to fit test data and calculate voltage endurance coefficients. As a contrast sample, the accelerated electrical stress aging test is also used to mineral oil-paper model. It is indicated that the relative permitivity of vegetable insulating oil is higher than that of mineral oil, so the electric field distribution in vegetable oil- paper insulation is more uniform than that in mineral oil-paper insulation. Therefore, the electrical aging behavior of vegetable oil-paper insulation is better than mineral oil-paper insulation.