IEC TS 60076-20:2017
(Main)Power transformers - Part 20: Energy efficiency
Power transformers - Part 20: Energy efficiency
IEC TS 60076-20:2017(E) is applicable to transformers in the scope of IEC 60076-1. It proposes two methods of defining an energy efficiency index and introduces three methods of evaluating the energy performance of a transformer. The appropriate method is chosen by agreement between purchasers and manufacturers or according to local regulations.
The contents of the corrigendum of January 2018 have been included in this copy.
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IEC TS 60076-20 ®
Edition 1.0 2017-01
TECHNICAL
SPECIFICATION
colour
inside
Power transformers –
Part 20: Energy efficiency
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IEC TS 60076-20 ®
Edition 1.0 2017-01
TECHNICAL
SPECIFICATION
colour
inside
Power transformers –
Part 20: Energy efficiency
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.180 ISBN 978-2-8322-3870-7
– 2 – IEC TS 60076-20:2017 © IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 8
3 Terms and definitions . 8
4 Efficiency and efficiency index calculation . 9
4.1 General . 9
4.2 Methods of evaluating energy performance . 10
4.3 Method A . 11
4.3.1 Efficiency index general formula . 11
4.3.2 Peak efficiency index . 11
4.4 Method B . 12
4.4.1 Efficiency index general formula (EI ) . 12
B
4.4.2 Efficiency index at 50 % loading (EI ) . 12
B50
5 Specification of energy performance . 13
6 Energy performance levels . 13
6.1 General . 13
6.2 Liquid immersed transformers . 14
6.2.1 Minimum PEI method A . 14
6.2.2 Maximum load losses and maximum no load losses for transformers
with rated frequency equal to 50 Hz . 16
6.2.3 Efficiency index method B . 17
6.3 Dry type transformers . 19
6.3.1 Minimum PEI value method A . 19
6.3.2 Maximum load loss and maximum no load loss for transformers with
rated frequency equal to 50 Hz . 21
6.3.3 Efficiency index method B at 50 % load factor . 22
7 Tolerance . 25
7.1 General . 25
7.2 Losses . 25
7.3 PEI . 25
Annex A (informative) Capitalisation of losses . 26
A.1 General theory, concept of capitalisation . 26
A.2 Impact of capitalisation values . 27
A.3 Capitalisation formula . 27
A.3.1 General . 27
A.3.2 Calculation of factor A. 28
A.3.3 Calculation of factor B. 28
A.3.4 Use of A and B for tender evaluation . 30
A.3.5 Determination of factors A and B . 31
Annex B (informative) Efficiency based on a survey of world practices . 32
B.1 General . 32
B.2 50 Hz efficiency . 32
B.3 60 Hz efficiency . 32
Annex C (informative) Japanese practices . 34
C.1 General . 34
C.2 Scope . 34
C.3 Maximum losses calculation methods . 34
C.4 Maximum losses . 34
Bibliography . 36
Figure A.1 – Load profile. 29
Table 1 – PEI values for single-phase transformers with U ≤ 12 kV and S ≤ 100 kVA . 14
m r
Table 2 – PEI values for transformers with U ≤ 36 kV and S ≤ 3 150 kVA . 15
m r
Table 3 – PEI values for transformers with U > 36 kV or S >3 150 kVA . 16
m r
Table 4 – Maximum load losses and maximum no load losses for transformers with
rated frequency equal to 50 Hz . 17
Table 5 – EI value for liquid-immersed 60 Hz transformers . 18
B50
Table 6 – EI value for liquid-immersed 50 Hz transformers . 19
B50
Table 7 – PEI values for dry type transformers with U ≤ 36 kV and S ≤ 3 150 kVA . 20
m r
Table 8 – PEI values for transformers with U ≤ 36 kV and S > 3 150 kVA . 20
m r
Table 9 – PEI values for transformers with U > 36 kV . 21
m
Table 10 – Maximum load loss and maximum no load loss for transformers with rated
frequency equal to 50 Hz . 22
Table 11 – EI values for single-phase dry type 60 Hz transformers . 23
B50
Table 12 – EI values for three-phase dry type 60 Hz transformers . 24
B50
Table 13 – EI values for dry type 50 Hz transformers . 25
B50
Table B.1 – Efficiency equations for transformers with a primary voltage of 36 kV and
below, from 5 kVA to 1 000 kVA single-phase and 15 kVA to 3 150 kVA three-phase,
50 Hz and 50 % load method A . 32
Table B.2 – Efficiency equations for transformers with a primary voltage of 36 kV and
below, from 5 kVA to 1 000 kVA single-phase and 15 kVA to 3 150 kVA three-phase,
60 Hz and 50 % load method B . 33
Table C.1 – Maximum losses . 35
– 4 – IEC TS 60076-20:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POWER TRANSFORMERS –
Part 20: Energy efficiency
FOREWORD
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