Exploring the Flashover Behaviour in Railway Traction Insulators

Lightning stroke causes damaging effect on any electrical system and deters the system reliability. Therefore, it is important to explore the insulator flashover behaviour due to lightning stroke. This paper intends to understand the flashover characteristics across stay arm and bracket insulator of an isolated railway traction mast. The overvoltage characteristics, insulator flashover characteristics along with its dependence on leader propagation and soil ionization is investigated. Using Electro-Magnetic Transient Program (EMTP) software, the modeling and simulation work is carried out. The simulation results have shown that insulator overvoltage and flashover behaviour are greatly influenced by the lightning magnitude and steepness. Also, the flashover characteristics are governed by leader growth across insulator and ionisation of soil. This information can be used to design or implement suitable Lightning Arrester to protect railway traction system.