Salt fog testing of polymer housed surge arresters

This paper deals with the evaluation of the insulation design of polymer housed surge arresters for distribution lines. Five commercial designs were tested in a salt fog chamber for 9 cycles using a cycle consisting of 120 hours of salt fog that was followed by a 48 hour rest period for a total of 1280 hours of salt fog. In these tests, the specification for the 1000-hour salt fog test in IEC 1109 for composite insulators was used as a guide. The results demonstrate that a comprehensive evaluation of the external and internal insulation design of polymer housed surge arresters can be obtained by performing a salt fog test, and as such, the test can be considered as a useful design test. Suggestions for improvements in the insulation design of all polymer housed surge arresters evaluated are given in the paper.