Challenges in developing surge arrester failure detection methodologies in TNB distribution network

“A surge arrestor that looks good is good”. Unfortunately, such statement is not always correct. Surge arrestors are passive and static components in a medium voltage overhead line (MVOH) system. Their main function is to absorb lightning induced energy and route it to ground in order to limit the effect of lightning overvoltage to overhead line equipment such as automatic circuit reclosers, sectionalizers, and load break switches. A surge arrestor has an average service life of between 10 to 15 years. However, the service life of surge arresters cannot be determined just by their chronological age but is also affected by the number of discharges that they have to endure. A surge arrestor that has discharged 15 to 25 full discharges can be considered as nearing its service end-of-life. With Malaysia having an isokeraunic level of 200 thunder days a year, determining the surge arrestor end-of-life is a major concern.