Recognition of partial discharge defects in cable terminations

As reported in very researches, the majority failure mechanism in cable terminations is predominantly involving partial discharge deterioration caused by voids, contaminants and protrusion. The partial discharge measurement is an effective way to detect such defects. However, no research shows the relation between the magnitude of partial discharge and remaining life of cable termination. Hence, it is hard to make decision to replace the unqualified cable termination immediately or lately for an in-service cable termination, while the partial discharge activities are measured. Based on authorspsila experiences, different defects have different ageing speed to breakdown. Therefore, recognition of defects is an alternative way to assess the degree of risks. This paper sets up a series test to figure out the properties of partial discharge activities caused by different defects, including wrong position of stress cone, void left, tape left, and needle pricked. Test results show the different properties of different defects, and these characteristics can be used to recognize defects inside cable termination.