IS 11182 : Part 3 : Sec 2 : 1996 Guide for evaluation of insulation systems of electrical equipments: Part 3 Electrical endurance test procedures Section 2 evaluation procedure based on extreme value distribution

1. Scope

1.1 This standard describes statistical procedures to analyze data on time-to-breakdown at constant voltage stress (or breakdown voltages under long-term increasing-voltage stress) of groups of individual specimens of electrical insulation systems, or models representinginst&ingsystems. Numericalexamplesare also included.

1.2 This standard assumes that the electrical factors of influence is the dominating ageing factor. If it is known or understood that more than one factor of influence is significant, reference should be made to IS 11182 (Part 7/ Set 1) : 1986 ‘Guide for evaluation of insulation systems of electrical equipment: Part 7 Multi factor functional testing, Section 1 Test procedures’.

1.3 This standard does not apply to data derived from short-time electrical breakdown tests except those used as diagnostic factors from other long-term factors of intluence. When used in this way for diagnosis of factors of influence other than electrical, reference should be made to other appropriate Indiau Standards given in 2 of this standard.