Nonlinear Corona Models in an Electromagnetic Transients Program (EMTP)

Corona attenuation and distortion of overvoltage waves is an important factor in determining the overvoltage level inside the electrical system due to atmospheric lightning discharges. Simulation of overvoltage wave propagation in electrical network by digital computers is often used in the electric power industry.1,2 This paper describes the implementation of a simple and accurate numerical model representing the non-linear corona phenomenon in a general purpose electromagnetic transients program (EMTP) for lightning overvolttage studies. Single phase representation of multi-phase transmission line for short distance below 2 km are used. Field test measurements on a 600 kV line, are duplicated with the transients program and the developed corona model. Corona loss constants are also obtained empirically under different conductor configuration and wave polarities.