The TSC characteristics of HTV composite insulators

This paper presents the thermally stimulated current (TSC) results obtained from an experiment which was carried out in order to identify the feasibility to evaluate the aging state of field HTV composite insulators by TSC technique. The test samples were prepared from four HTV composite insulators, which were randomly picked in-situ. The TSC experimental results show that the rough TSC shapes of four samples were similar despite different serving time, while the peak at high temperature area was only observed in one sample (insulator C). Further calculated results indicate that insulator C had the deepest trap level in our investigation. The performance difference between insulator C and the other three insulators can be obviously observed from the SEM morphologies, but is difficult to discern from their corresponding HC levels. Based on the above results, we can infer that although there are certain inner relations between the TSC characteristics of HTV composite insulators and their hydrophobicity, comparing to the later, the former is more sensitive to the aging performance under some conditions. Also the aging states of field HTV composite insulators have no direct relations with the servicing time in our investigation, when the TSC characteristics are taken into account