Contamination performance of silicone rubber cable termination

This paper describes new laboratory test methods employed to evaluate the performance of silicone rubber materials under simulated outdoor contamination conditions. Details of a newly designed chamber also are presented here. The chamber utilizes no moving parts and involves no metallic components. Cold shrink cable termination from three manufacturers (A, B and C) were tested in both Detroit Edison old and new tracking chambers. Two samples from each product were tested in each chamber. All samples tested in the old tracking chamber failed the test within the first 600 hours of testing. Measurement of moisture inside the old tracking chamber during the dry and wet cycle of the test reveals that the chamber does not get completely devoid of moisture vapor during the non-spray cycle. Five samples out of six successfully completed the tracking test performed using the new tracking chamber. Only sample C1 failed the test. Both samples A successfully completed the test with no signs of erosion or tracking. The leakage current measurements of these samples show that the insulators maintained their surface hydrophobicity through out the entire duration of test. Although, both samples B completed the 3,000 hour tracking test, they show signs of material deterioration towards the end of test. This is supported by the sharp increase in the leakage current activities.