Numerical Simulation of the Lightning Impulse Flashover of 11 kV Polymeric Insulator

The proposed model helps predict the Lightning Impulse Flashover Voltage (LIFOV) of the overhead polymeric line insulators and the process by which the flashover gets established. The two-dimensional axisymmetric model of the 11 kV polymeric insulator is designed in COMSOL Multiphysics. The air surrounding the insulator is considered a mixture of Nitrogen and Oxygen in a ratio of 4:1. The ionization of the air surrounding the insulator is simulated for various voltages above its Basic Insulation Level (BIL) by solving the drift-diffusion equation in the air domain. The initiation and progression of electron streamers from the high voltage and ground electrode at various time instants is observed, eventually resulting in a complete flashover of the system. The predicted LIFOV of the 11 kV polymeric insulator is validated against the experimentally measured LIFOV.