Reaffirmed 2024

NATIONAL FOREWORD

This Indian Standard (Part 300) which is identical with IEC 62271-300 : 2006 ‘High-voltage switchgear and controlgear — Part 300: Seismic qualification of alternating current circuitbreakers’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on the recommendation of the High Voltage Switchgear and Controlgear Sectional Committee and approval of the Electrotechnical Division Council.

This standard specifies seismic severity levels and gives a choice of methods that can be applied to demonstrate the performance of HV circuit-breakers for which seismic qualification is required.

This standard supersedes and replaces IS 14674 : 1999 ‘High-voltage alternating current circuitbreakers — Guide for seismic qualification of high-voltage alternating current circuit-breakers’. IS 14674 is identical with IEC 1166 : 1993 which, has since been withdrawn and replaced by IEC 62271-300 : 2006.

The text of IEC Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are however not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker.