Expulsion protective gaps on 132 kv lines

During the last few years, the expulsion protective gap, consisting of an arrangement of spark gaps inside of fiber tubes and in series with an external gap, has been applied to a few medium voltage transmission lines for protection against outage due to lightning. The first extensive application of such gaps on 2 typical 132 kv lines during the past 2 lightning seasons are presented herewith. These expulsion protective gaps are shown to be an effective device for preventing lightning flashovers of a line and reducing line outage.