Doc: ET 16(6636) IS 2026(Part 1) IEC 60076-1:2011 …

1 Doc: et 16 ( 6636 ). IS 2026 ( part 1). IEC 60076 -1: 2011 . BUREAU OF INDIAN STANDARDS. DRAFT FOR COMMENTS ONLY. (Not to be reproduced without the permission of BIS or used as a STANDARD). Draft Indian Standard POWER TRANSFORMERS part 1: GENERAL. (Second Revision). Last date for receipt of comments is: 25-07-2013. _____. Power Transformers Sectional Committee, et 16 . NATIONAL FOREWORD. This draft Indian Standard (second revision) which is identical with IEC 60076 -1: 2011 . Power transformers: part 1 General' issued by the International Electrotechnical Commission (IEC) is proposed to be adopted by the Bureau of Indian Standards on the recommendation of the Transformers Sectional Committee and approval of the Electrotechnical Division Council.

2 This standard was first published in 1962 and covered naturally cooled oil-immersed transformers. With subsequent amendments forced cooled transformers were included, use of synthetic liquids as cooling medium was permitted and requirements for aluminium winding were incorporated. First revision was undertaken with a view to bringing it in line with the revision of IEC. 76:1967 Power transformers'. The second revision has been based on IEC 60076 -1:2000. Power 1: General' issued by the International Electrotechnical Commission with following modifications.

3 In this revision the temperature of ambient air and cooling medium oil is as per Indian Environment and tests are conducted accordingly. In this revision it is completely aligned with latest IEC standard. The text of the IEC standard has been approved as suitable for publication as 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'.

4 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. In this adopted standard, references appear to certain International Standards for which Indian Standard also exist. The corresponding Indian Standard, which are to be substituted in their respective places are listed below along with their degree of equivalence for the editions indicated: BISDG NOTE A separate standard on Distribution Transformer (IS 1180) is available for rating upto 2500 kVa (Under revision).

5 These ratings are also covered in IS 2026 -1. Therefore suitable para may be added to exclude DT from the scope of the standard. Moreover, ratings, ambient temperature etc. need to be looked into from Indian perspective members are requested to comment on this. International Standard Corresponding Indian Standard Degree of Equivalence IEC 60076 -2, Power transformers part IS 2026 ( part 2):2010 Power Technically 2: Temperature rise for liquid-immersed Transformers - part 2 Temperature Equivalent transformers rise (first revision).

6 IEC 60076 -3:2000, Power transformers IS 2026 ( part 3):2009 Power Identical part 3: Insulation levels, dielectric tests Transformers - part 3 Insulation and external clearances in air levels, dielectric tests and external clearances in air (third revision). IEC 60076 -5:2006, Power transformers IS 2026 ( part 5): 2011 Power Technically part 5: Ability to withstand short circuit Transformers - part 5 Ability to Equivalent withstand short circuit (first revision). IEC 60076 -10:2001, Power transformers IS 2026 ( part 10):2009 Power Identical part 10: Determination of sound levels Transformers - part 10 Determination of sound levels IEC 60076 -11:2004, Power transformers IS 11171:1098 Dry-Type Power Technically part 11: Dry-type transformers Transformers Equivalent IEC 60137:2008, Insulated bushings for IS 2099 : 1986 Bushings for Identical alternating voltages above 1 000 V alternating voltages above 1000 volts (Second Revision).

7 IEC 60214-1:2003, Tap-changers part IS 8468:1977 On-load Tap Changers Not Equivalent 1: Performance requirements and test methods IEC 60296:2003, Fluids for IS 335:1993 New Insulating Oils Do electrotechnical applications Unused mineral insulating oils for transformers and switchgear ISO 9001:2008, Quality management IS/ISO 9001:2001 Quality Identical systems Requirements Management Systems - Requirements The Technical Committee responsible for the preparation of this standard has reviewed the provisions of the following International Standards referred to in this adopted standard and has decided that they are acceptable for use in conjunction with this standard.

8 International Standard Title IEC 60721-3-4:1995 Classification of environmental conditions part 3: Classification of groups of environmental parameters and their severities Section 4: Stationary use at nonweather protected locations Only English language text has been retained while adopting it in this Indian Standard and as such the page numbers given here are not the same as in the International Standard For the purpose of deciding whether a particular requirement of this standard is complied with the final value, observed or calculated, expressing the result of a test or analysis shall be rounded off in accordance with IS 2:1960 Rules for rounding off numerical values (revised)'.

9 The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. Note: The technical content of the documents is not available on website. For details, please refer the corresponding IEC 60076 -1: 2011 or kindly contact: Head Electrotechnical Department Bureau of Indian Standards 9, B. S. Zafar Marg, New Delhi-110002. Email: Telephone/ fax: 011-23231192.