天然酯绝缘油与矿物绝缘油混油后变压器温升特性的仿真分析

Simulation Analysis on Temperature Rise Characteristics of Transformer After Mixing Mineral Insulating Oil with Natural Ester Insulating Oil

以矿物绝缘油与天然酯绝缘油的混合油作为研究对象,仿真对比研究不同比例混合油应用于变压器中时变压器内部温度场及流体场的分布情况。首先建立了二维变压器绕组简化模型,然后结合混合油的热力学参数及变压器绕组的损耗功率,利用有限容积法计算了变压器的温度场及流体场。仿真计算结果表明:模型内部温度场同时受绕组损耗与散热速率的影响,随着混合油中矿物油比例的逐渐减小,混合油的运动黏度不断增加,促使变压器的散热效率降低,但是混合油的比热容与热导率会不断增加。两者的共同作用导致随着混合油中矿物油比例的不断减少,变压器的绕组温升及油平均温升整体呈上升趋势。

Using the mixed oil of mineral insulating oil and natural ester insulating oil as research object,a simplified two-dimensional transformer winding model was established.Combining with the thermodynamic parameters of mixed oil and the loss power of transformer winding,the temperature field and fluid field of transformer were calculated by finite volume method.The simulation results show that the internal temperature field of model is affected by the winding loss and heat dissipation rate at the same time.With the decrease of the mineral oil percentage in the mixed oil,the kinematic viscosity of the mixed oil increases,and the heat dissipation efficiency of transformer reduces,but the specific heat capacity and thermal conductivity of the mixed oil continue to increase,which makes the temperature rise of transformer winding and average temperature rise of oil increase monotonously with the decrease of mineral oil percentage in the mixed oil.