Risk Assessment of Surge Arresters for Efficient Maintenance of Medium-voltage Distribution Lines

In the lightning protection design of medium-voltage distribution lines, the introduction of arcing horns with a zinc-oxide element to protect the insulated cables and insulators and primary cutout with a zinc-oxide element to protect transformers have reduced the damage by direct lightning strikes. However, the failure rate of lightning arrester elements used in these power distribution systems is increasing. In this study, we evaluated the failure risk of lightning arrester elements installed on utility poles based on the probability of lightning strikes exceeding the energy tolerance of each surge arrester element. As a result, when the insulators on a pole are unprotected, the elements of arresters installed on the poles adjacent to it on its either side and supporting the same phase line will have the highest failure risk.