ATP-EMTP modelling of the negative lightning impulse flashover of a 24 kV silicone line pin insulator

Negative lightning impulse flashover of a 24 kV silicone line pin insulator is modeled by implementing the CIGRE leader progression model with appropriately adjusted parameters in ATP-EMTP environment. Flashover characteristics were experimentally obtained via oscillographic monitoring of the applied impulse voltage and discharge current. Flashover initiates through streamer coronas, followed by the inception of a small leader; the latter is required for flash-over to occur. A very good agreement exists between experimental results and simulations on impulse discharge incep-tion and growth characteristics. This is achieved by employing in modeling overvoltage dependent leader inception voltage and charge per unit length, owing to the relatively short length of the evaluated distribution line insulator.