Insulation co-ordination of rural distribution lines

Lightning is by far the most frequent cause of power interruptions on rural distribution lines in South Africa's Highveld. Flash density varies between five and twelve flashes per square kilometre per year [1, 2]. Eskom (South Africa's major generation and bulk transmission utility, responsible for most rural distribution) currently operates some 150 000 km of rural distribution lines (11 kV and 22 kV, woodpole construction) throughout the country.