牵引变压器中运动金属颗粒群的分布状态及影响因素仿真研究

Simulation Study on Distribution and Influence Factors of Metal Particles in Traction Transformer

针对牵引变压器油中金属颗粒群引起的放电问题,以Fluent软件为计算工具,采用固–液两相流理论中的Euler-Lagrange方法模拟牵引变压器内部油道中运动金属颗粒群的分布状态。用标准k-ε(k为湍动能,ε为湍能的耗散率)湍流模型对流动的变压器油进行描述,同时用颗粒轨道模型对油中金属颗粒群进行描述。在对颗粒轨道模型进行定义时,从颗粒受力情况、颗粒湍流扩散以及固–液两相耦合3方面进行设置,从变压器油中金属颗粒尺寸、油流速度和油道电场强度等方面进行精确定义。模拟结果表明:流动状态下金属颗粒群沿牵引变压器油道运动时,其运动分布状态决定了金属颗粒与电极之间的碰撞频次,且颗粒尺寸的增大、油流速度的减小及油道电场强度的增大都会使局部放电更加剧烈。金属颗粒群的分布状态会影响流动变压器油的绝缘性能。

Aiming at the discharge problem caused by metal particles group in traction transformer oil, using the Fluent software as computing tool, we used the Euler-Lagrange method in the theory of solid-liquid two phase flow to simulate the distribution state of metal particles in the oil tract of traction transformer. Mobile transformer oil was described by the standard k-e turbulence model, the metal particles in the oil was described by the particle trajectory model. When defining the particle trajectory model, three aspects of the stress state of particles, the particle turbulent diffusion, and the sol- id-liquid two-phase coupling were set up. A precise definition of the metal particle size, oil flow velocity, and electric field strength was made. Simulation results show that when metal particle group moves along the traction transformer oil tract, the motion distribution state will decide the collision frequency between metal particles and electrodes; meanwhile,the decrease of particle size, the decrease of oil flow velocity, and the increase of electric field strength will intensify the par- tial discharge. The distribution of metal particles group may affect the insulation performance of mobile transformer oil.