Analysis of Ion Flow Field Characteristics of High-Speed Railway Contact Line

Ion current is generated around the contact line of high-speed railway due to the corona effect. Ion current will increase the space charge density and affect the spatial electric field distribution on the roof, thereby affecting the insulation performance outside the roof, which may cause insulation flashover accidents. In this paper, according to the distribution of ion flow field near the 27.5 kV contact line of high-speed railway, the distribution characteristics of ion flow field around the contact line under the influence of different airflow velocities are analyzed by finite element simulation. The research shows that the electric field intensity around the contact line changes with the increase of airflow velocity, and the peak value of the roof synthetic field intensity decreases under the influence of airflow. Under the influence of high-speed airflow, the distribution range of spatial ion flow density is obviously biased towards the windward side, and the ion flow distribution is concentrated in the upper space of the roof, resulting in an increase in the distribution range of ion flow in the contact line-top space. The research results can provide a scientific basis for the optimization of roof external insulation design and the analysis of roof electromagnetic interference.