ICS 29.120.70                          ETD 35

Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 127) which is identical with IEC 60255-127 : 2010 ‘Measuring relays and protection equipment — Part 127 Functional requirements for over/under voltage protection’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on the recommendation of the Power Systems Relays Sectional Committee and approval of the Electrotechnical Division Council.

This standard is a part of series of standards based on IEC 60255 series which shall replace IS 3231 series on adoption. Other parts of the series are:

Part 1 Common requirements

Part 5 Insulation coordination for measuring relays and protection equipment — Requirements and tests

Part 8 Thermal electrical relays

Part 11 Voltage dips, short interruptions, variations and ripple on auxiliary power supply port

Part 12 Directional relays and power relays with two input energizing quantities

Part 13 Biased (percentage) differential relays

Part 16 Impedance measuring relays

Part 21 Vibration, shock, bump and seismic tests on measuring relays and protection equipment

Section 1 Vibration tests (sinusoidal)

Section 2 Shock and bump tests

Section 3 Seismic tests

Part 22 Electrical disturbance tests

Section 1 1 MHz burst immunity tests

Section 2 Electrostatic discharge tests

Section 3 Radiated electromagnetic field immunity

Section 4 Electrical fast transient/burst immunity test

Section 5 Surge immunity test

Section 6 Immunity to conducted disturbances induced by radio frequency fields

Section 7 Power frequency immunity tests

Part 24 Common format for transient data exchange (COMTRADE) for power systems

Part 25 Electromagnetic emission tests for measuring relays and protection equipment

Part 26 Electromagnetic compatibility requirements

Part 27 Product safety requirements

Part 151 Functional requirements for over/under current protection

The text of IEC Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminology and 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.