Improving the Performance of a Wildlife Protection Cap by the Use of Salt Fog Testing

Dielectric caps are used as wildlife protection measures on a new line of switching devices in order to satisfy service continuity needs and environmental requirements. Fog chamber tests were used to check and evaluate the performance of six different wildlife protection caps, positioned on their insulators, and outfitted with the appropriate connecting cables. The length of the test cycle was three weeks. During their performance evaluation, the energized insulators were exposed cyclically to salt fog. The energizing voltage was (27/1.73) = 15.6 kV(rms). Deionized water was used to produce the salt fog, with appropriate amount of salt added, to simulate a "heavy" contamination environment. The six insulators together with their caps were energized continuously for 24 hours a day, 7 days a week. The performance of two dielectric caps satisfied the expectations. The performance of dielectric caps made of various materials, and the design of the caps in terms of their shape and other aspects are described.