ICS 29.080.30                          ETD 19

Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 4) (First Revision) which is identical with IEC 60664- 4 : 2005 ‘Insulation coordination for equipment within low-voltage systems — Part 4: Consideration of high-frequency voltage stress’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on the recommendation of the High Voltage Engineering Sectional Committee and approval of the Electrotechnical Division Council.

This standard was earlier published in 2003. This revision has been undertaken to align it with the latest version of IEC 60664-4.

The major changes made during the revision of IEC 60664-4 were the following:

a) Inclusion of more recent information about the withstand characteristics of insulation at high-frequency voltage stress (see Annexes A, B and C).

b) Inclusion of requirements for the dimensioning of clearances at high-frequency voltage stress (see 4).

c) Inclusion of requirements for the dimensioning of creepage distances at high-frequency voltage stress (see 5).

d) Inclusion of requirements for the dimensioning of solid insulation at high-frequency voltage stress (see 6).

e) Inclusion of diagrams to provide guidance on dimensioning with respect to high-frequency voltage stress (see Annex F).

f) Specification of tests with respect to high-frequency voltage stress (see 7).

g) Inclusion of test circuits for high-frequency voltage withstand testing and partial discharge testing (see Annex D.1 and D.2.1).

h) Inclusion of design criteria for partial discharge test circuits at high-frequency voltage (see Annex D.2.2).

j) Inclusion of criteria for dealing with non sinusoidal voltage stress (see 8 and Annex E).

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.