Surge arrester faults and their causes at eThekwini electricity

Abstract

Failures in polymeric housed surge arresters have recently increased. This has resulted in a number of studies being done in order to establish the condition of surge arresters whilst in service, the aim being to remove them from service before they failed. This paper utilizes a thermovision technique to predict potential faults allied to a visual inspection of arresters placed in eThekwini outdoor substations. Infrared analysis was valuable in obtaining sufficient information on arrester failures by detecting hotspots within the arresters while still connected to the system and comparing these test results with those performed on failed units. During the visual internal inspection of arresters evidence of punctures, treeing, tracking and moisture masks were noted on ZnO blocks and seals.