Ice progressive stress method: repeatability during full-scale testing of 400 kV line and apparatus insulators and application of the test results

The ice progressive stress (IPS) method fulfils international requirements and has been included by IEEE in the position paper of accepted ice test procedures Farzanch, M. et al. (2003). The present paper analyses the repeatability of the test results of 400 kV voltage class line cap-and-pin/long rod insulators and circuit breakers. The results of the tests of nine different types of full-scale insulator strings and three different types of full-scale T-formed circuit breakers are analyzed. The analysis of the repeatability showed that the results are repeatable in terms of the variation of the different test parameters. The statistical test results in the form of 50% flashover voltage and standard deviation are completely applicable for the statistical dimensioning (availability calculations) using specially developed computer program. Examples are presented in the paper.