Externally gapped line arresters - First experience with the new IEC 60099-8 standard and Line study analysis

Surge arresters installed on a transmission line are termed Line Surge Arresters (LSA). These arresters are commonly used to address lightning- related phenomena with the intent to improve the overall reliability of transmission lines. In contrast to the purpose of station arrester installation LSAs task is not the protection of local insulation systems, like bushings, cable terminations, electrical machines etc. LSAs must prevent uncontrolled flashovers of transmission line insulators in order to prevent earth faults and short circuits “inside” of the system component “transmission line”. Thus, Line Surge Arresters can substantially improve the system reliability by reducing the earth, multi-phase and multi-circuit line outage rates.