CONTAMINATION PERFORMANCE OF SILICONE-RUBBER CABLE TERMINATIONS

This paper describes the results of a systematic study to understand the performance of silicone rubber terminations under contaminated conditions. The terminations evaluated were 15 kV class "cold shrink" type for concentric neutral cables. They were evaluated in a fog chamber where experimental conditions, such as, the electric stress, water conductivity, water flow rate and the deenergization time between subsequent fog chamber exposures were varied in order to alter the test severity. Changes in the surface hydrophobicity were monitored periodically by analyzing the samples using ESCA (Electron Spectroscopy for Chemical Analysis), SEM (Scanning Electron Microscopy) and contact angle measuring techniques. The results indicate that the experimental conditions play a significant role in the outcome of the tests. The dynamic characteristic of the recovery of hydrophobicity exhibited by silicone rubber has an important bearing in the selection of test parameters for accelerated evaluation of these terminations. It has been demonstrated that the recovery of hydrophobicity can be studied using several techniques.