植物绝缘油抑制离子迁移的动力学机制研究

Study on the Dynamic Mechanism of Inhibited Ion Mobility in Vegetable Insulating Oil

油纸界面的离子累积效应对换流变压器的绝缘性能有重要影响,应用低离子迁移率的绝缘油有助于减少离子的界面积累效应。专家学者们发现植物油的离子迁移率显著低于矿物油,具有明显优势,但其低离子迁移率的内在机制仍不清楚。因此,该文开展绝缘油的离子迁移率实验测试,并采用微尺度计算对离子迁移的微观机理进行研究。结果表明,在变压器工作温度下,植物油的离子迁移率低于矿物油一个数量级;微尺度计算分析发现,植物油分子具有高静电势表面,能够吸附油中离子自组装耦合形成团簇,使其具备抑制离子迁移的能力;在低于1.0V·nm^(-1)的场强下,植物油能够有效降低离子的电场响应性,减少离子在油纸界面的积累;超过1.0V·nm^(-1),团簇解耦,离子溢出,植物油的抑制能力减弱。

Ion accumulation at the oil-paper interface is critical in determining the insulation of converter transformers.Using insulating oils with low ion mobility can suppress accumulation.Vegetable oil’s ion mobility is much lower than mineral oil,but the fundamental mechanism is unclear.Reversal polarity experiments and molecular computing are conducted to investigate insulating oils’ion mobility mechanism.Results show vegetable oil's ion mobility is 10-fold lower than mineral oil under converter transformer temperatures.Molecular computing has found self-assembled ion-vegetable oil clusters,where ions adsorb vegetable oil’s high electrostatic potential surface,restrict ion mobility.With weak or moderate electric fields(d1.0V/nm),vegetable oil reduces ion accumulation by decreasing ion mobility.With strong electric fields(>1.0V/nm),vegetable oil’s suppression capability weakens due to cluster decoupling.