关键词: 纳米变压器油, 纳米二氧化钛, 热分解动力学, 热重法, 升温速率, 活化能, 线性相关系数

Abstract: Nano-modification technique has shown a great potential in improving breakdown strength and aging property of transformer oil/paper insulation system. The thermal degradation process and property of nanoparticle modified transformer oil(nanofluid) play an important role in its practical applications. Based on thermal degradation kinetics theory, thermal degradation process of TiO2 nanofluid is investigated by using thermogravimetric method (TG) under five heating rates (5, 10, 15, 20 and 25 ℃/min). The main kinetic parameters of nanofluid is obtained respectively by using differential and integral method. The results indicate that mean activation energy of nanofluid is up to 61.38 kJ/mol and the obtained value is affected by the calculation methods. FWO method is more reliable than other methods with a correlation coefficient up to 0.997 80. The activation energy of the TiO2 nanofluid calculated by FWO method is 63.37 kJ/mol. All these results illustrate that nanomaterial-modification can increase the activation energy of transformer oil and improve its thermal decomposition behavior. This method provides a basis for thermal stability evaluation and overall performance of nanofluid.

Key words: transformer oil-based nanofluid, TiO2 nanomaterial, thermal degradation kinetic, thermogravimetric method, heating rate, activation energy, correlation coefficient