Characterisation of power system events on South African transmission power lines

Records of faults occurring on the South African power transmission system over a 16-year period have been collected. Over 12,000 faults were analysed to find statistical relationships between local climate, key design parameters of the overhead lines, and the main causes of power system faults identified as bird streamers, lightning, fire and pollution. The results characterise the performance of the South African transmission system on a probabilistic basis and illustrate differences in fault cause statistics for the summer and winter rainfall areas of South Africa and for different times of the year and day. The analysis illustrates the effectiveness of bird guards on towers.

► The main fault causes of transmission line faults in South Africa are lightning, fire, bird streamers and pollution.
► Over 12,000 faults have been analysed.
► A method is presented relating transmission line faults to the regional climate classified by the dominant rainfall type.
► The statistical significance is established of the differences between mean fault frequencies for fault causes, climate, time of day and season.
► The effectiveness of bird guards is illustrated.