John Tarilanyo Afa

The Lightning Performance of High Voltage Transmission Line John Tarilanyo Afa

Technical Report from the year 2011 in the subject Engineering - Power Engineering, grade: A, Atlantic International University (Niger Delta University), course: LPH 657, language: English, abstract: Lightning is a major source of danger to H. V transmission lines resulting in serious overvoltage which may cause flashover, puncture and sometimes loss of transmission line up to few hours or complete destruction of lines. The study is focused on Bayelsa State whose coastal areas occupy about eighty percent of the state. Due to its geographical location (Mangrove swamp forest) especially the coastal areas, these are areas of high thunderstorm and lightning days per year. This will pose significant influence on transmission line performance. From the present load with the proposed projects when completed may demand bulk power supply. The need of using high voltage transmission lines is there. Presently, it is expected that 132kv line may run from Yenagoa to Brass through Ogbia. It is therefore necessary to study the line performance in these areas of high Isokeraunic level. Lightning faults may be single or multi-phase and their elimination causes reclosing cycles, voltage dips and outages. Therefore the outage rate of a line and the quality of the delivered voltage depends on the lightning performance of the line. No transmission line design can be considered lightning proof, nor designers aimed at this goal. An acceptable design is to allow a certain number of outage per 100km of line or other line durations (Razevig 2003, Uglesic 2009). The probability of an outage depends on many factors which are statistical in nature that a worst case design is neither practical nor economical.