Contamination performance of silicone rubber cable terminations. II

For pt.1 see IEEE Trans. Power Deliv., vol.6, no.4, p.1366-73 (1991). This study is a follow-up of a previous report describing a systematic study of the contamination performance of silicone rubber cable terminations in a fog chamber. The goal of the study is to aid the development of an artificial contamination laboratory test for evaluating the electrical performance of all types of polymeric terminations in the field. This is achieved by understanding the role played by the various experimental factors on the electrical performance. The effect of varying the test method off-time on the regeneration of the silicon rubber´s hydrophobic or water repellant surface is studied. The effect of load current on dry band arcing, which occurs on a moist and contaminated surface of an energized termination and can result in material degradation or flashover, has also been evaluated. It has been shown for the first time that the surface temperature rise due to the full load current causes a significant reduction in dry band arcing activity and therefore has a beneficial effect on the contamination performance of polymeric terminations