Lightning performance improvement of the Swaziland electricity board transmission system (66kV & 132kV lines) - results of the pilot project

The prevalence of high lightning activity in Swaziland negatively affects the quality and reliability of power supply to the SEB Customers. More than 50% of power outages on transmission overhead lines are attributed to lightning. Owing to the good operating characteristics of metal oxide varistors lightning related power outages have been effectively optimized in many parts of the world utilizing zinc oxide transmission line surge arresters. A pilot project was undertaken to install transmission zinc oxide (ZnO) surge arresters in one of the most affected 66 kV lines in the country. Implementation took place in August 2003 (Spring) at the beginning of the lightning season. This paper presents an out line of how the project was conducted and its outcome