纳米粒子对变压器油中流注发展过程影响的仿真分析

Simulation Analysis of the Effect of Nanoparticles on Streamer Development in Transformer Oil

为进一步了解纳米粒子对变压器绝缘油性能改进的影响机理,根据纳米粒子的作用机制,建立了纳米粒子改性变压器油的场致分子电离流注发展模型。模型中电子、正电荷、负电荷以及负极性纳米粒子的流体力学连续性方程和Poisson方程相互耦合。通过仿真获得并对比了纳米改性变压器油和纯油中流注发展过程中的电场、空间电荷、流注半径、流注发展速率等参数。结果表明:纳米粒子的存在降低了纳米油流注通道中电子的数量,从而增加了流注头部空间电荷密度,流注半径尺寸受到抑制,流注发展速率降低。最后从负极性纳米粒子的电荷分布特征,得出纳米改性变压器油绝缘性能提高的根本原因是纳米粒子对电子的捕获。

To further understand how nanoparticle component improves transformer oil, we established an electric field dependent molecular ionization model of streamer development in transformer oil based on the working mechanism of nanoparticles. In the model, the continuum equations of electrons, positive and negative ions, and negatively charged nanoparticles are coupled with Poisson equations. Through calculations with the model, we obtained and compared the electric field distribution, space charge distribution, streamer radius, streamer velocity, etc. during streamer developments in transformer oil and oil-based nanofluid. The results show that, the appearance of nanoparticles in oil reduces electrons in streamer channels, thereby the space charge in streamer head increases, the radius of streamer is condensed, and the streamer velocity decreases significantly. The distribution of negative charge density indicates that the electron attachment to conductive nanoparticles in oil is the root cause of the oil performance improvement.