Power transformers - Additional European requirements: Part 2-1 Medium power transformer - General requirements

The scope of this document is to define the energy performance of Medium Power Transformers in compliance with prEN 50708-1-1:2019.

Leistungstransformatoren - Zusätzliche europäische Anforderungen - Teil 2-1: Mittlere Leistungstransformatoren

Transformateurs de puissance - Exigences européennes supplémentaires : Partie 2-1 Transformateurs de moyenne puissance

Le domaine d'application du présent document doit définir les performances énergétiques des transformateurs de moyenne puissance selon le prEN 50708-1-1:2019.

Močnostni transformatorji - Dodatne evropske zahteve - 2-1. del: Srednji močnostni transformator- Splošne zahteve

General Information

Status
Published
Publication Date
28-May-2020
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
28-May-2020
Due Date
02-Aug-2020
Completion Date
29-May-2020

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SLOVENSKI STANDARD
SIST EN 50708-2-1:2020
01-julij-2020
Nadomešča:
SIST EN 50588-1:2017
Močnostni transformatorji - Dodatne evropske zahteve - 2-1. del: Srednji
močnostni transformator- Splošne zahteve
Power transformers - Additional European requirements: Part 2-1 Medium power
transformer - General requirements

Transformateurs de puissance - Exigences européennes supplémentaires : Partie 2-1

Transformateurs de moyenne puissance
Ta slovenski standard je istoveten z: EN 50708-2-1:2020
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
SIST EN 50708-2-1:2020 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50708-2-1:2020
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SIST EN 50708-2-1:2020
EUROPEAN STANDARD EN 50708-2-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2020
ICS 29.180 Supersedes EN 50588-1:2017 (PART) and all of its
amendments and corrigenda (if any)
English Version
Power transformers - Additional European requirements: Part 2-
1 Medium power transformer - General requirements
Transformateurs de puissance - Exigences européennes To be completed
supplémentaires : Partie 2-1 Transformateurs de moyenne
puissance

This European Standard was approved by CENELEC on 2019-10-09. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 50708-2-1:2020 E
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SIST EN 50708-2-1:2020
EN 50708-2-1:2020 (E)
Contents

European foreword ......................................................................................................... 3

Introduction .................................................................................................................... 4

1 Scope ...................................................................................................................... 5

2 Normative references ............................................................................................... 5

3 Terms and definitions ............................................................................................... 5

4 Service conditions .................................................................................................... 5

5 Rating and general requirements.............................................................................. 5

5.1 General ........................................................................................................... 5

5.1.1 Highest voltages for equipment for winding with U > 1,1 kV .............. 5

5.1.2 Rated voltage for winding with Um ≤ 1,1 kV ......................................... 5

5.1.3 Tapping ............................................................................................... 6

5.1.4 Connection designations for three phase transformers ........................ 6

5.2 Energy Performance ....................................................................................... 6

5.2.1 General ............................................................................................... 6

5.2.2 Transformers with special requirements .............................................. 9

6 Rating plate............................................................................................................ 11

7 Tolerances during factory acceptance tests ............................................................ 11

8 Tests ...................................................................................................................... 11

9 Accessories and fittings ......................................................................................... 11

10 Capitalization losses .............................................................................................. 11

11 Transformers overhaul ........................................................................................... 11

Annex ZZ (informative) Relationship between this European Standard and the ecodesign

requirements of Commission Regulation (EU) No 548/2014 of 21 May 2014 and its
amendment No 2019/1783 of 1 October 2019 on implementing Directive 2009/125/EC

of the European Parliament and of the Council with regard to small, medium and large

power transformers aimed to be covered ................................................................ 12

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SIST EN 50708-2-1:2020
EN 50708-2-1:2020 (E)
European foreword

This document (EN 50708-2-1:2020) has been prepared by CLC/TC 14 “Power transformers”.

The following dates are fixed:
• latest date by which this document has (dop) 2020-11-22
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2023-05-22
standards conflicting with this document
have to be withdrawn

This document supersedes EN 50588-1:2017 and all of its amendments and corrigenda (if any).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

This document has been prepared under a mandate given to CENELEC by the European Commission

and the European Free Trade Association and supports essential requirements of EU Directive(s).

For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this

document.
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SIST EN 50708-2-1:2020
EN 50708-2-1:2020 (E)
Introduction

For the purpose of this document, the requirements of the general EN 50708-1-1:2020 apply.

This document contains particular requirements for specific transformers or transformer applications,

which are based on the requirements of the general EN 50708-1-1:2020.

This document should be considered in conjunction with the requirements of the general parts.

The particular requirements of the different subparts of EN 50708 supplement, modify or replace

certain requirements of the general parts of EN 50708-1 and/or EN 50708-1-X being valid at the time

of publication of this document. The absence of references to the exclusion of a part or a clause of a

general part means that the corresponding clauses of the general part are applicable (undated

reference).

Requirements of other -X parts with X greater than 1 being eventually relevant for cases covered by

this document also apply. This document could therefore also supplement, modify or replace certain

of these requirements valid at the time of publication of this document.

The main clause numbering of each part follows the pattern and corresponding references of

EN 50708-1-1:2020. The numbers following the particular number of this document are those of the

corresponding parts, or clauses of the other parts of the EN 50708 series, valid at the time of

publication of this document, as indicated in the normative references of this document (dated

reference).

In the case where new or amended general parts with modified numbering were published after the

subpart was issued, the clause numbers referring to a general part in subparts might no longer align

with the latest edition of the general part. Dated references should be observed.

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SIST EN 50708-2-1:2020
EN 50708-2-1:2020 (E)
1 Scope

The scope of this document is to define the energy performance of Medium Power Transformers in

compliance with EN 50708-1-1:2020.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments)

applies.

EN 50708-1-1:2020, Power transformers - Additional European requirements: Part 1-1: Common part

- General requirements
EN 60076-1:2011, Power transformers - Part 1: General

EN 60076-3:2013, Power transformers - Part 3: Insulation levels, dielectric tests and external

clearances in air
EN IEC 60076-11:2018, Power transformers - Part 11: Dry-type transformers
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 50708-1-1:2020 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
4 Service conditions
See EN 60076-1:2011.
5 Rating and general requirements
5.1 General
5.1.1 Highest voltages for equipment for winding with U > 1,1 kV

Insulation levels and dielectric test shall be in accordance with the requirements of EN 60076-3:2013

and for dry type transformers in accordance with EN IEC 60076-11:2018.
The values of the highest voltage U for equipment are:
3,6 kV– 7,2 kV – 12 kV – 17,5 kV – 24 kV – 36 kV

NOTE National practices might require the use of highest voltages for equipment up to (but not including)

52 kV, when the rated voltage is less than 36 kV (such as U = 38,5 kV or U = 40,5 kV).

m m
5.1.2 Rated voltage for winding with Um ≤ 1,1 kV

For U ≤ 1,1 kV, the preferred rated voltage value shall be chosen in the hereunder list:

400 V – 410 V – 415 V – 420 V – 433 V – 690 V

This document may be applied either as a whole or in part, to transformers with rated low voltages

below 400 V and above 690 V.
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SIST EN 50708-2-1:2020
EN 50708-2-1:2020 (E)

The values for short duration power frequency withstand and/or for the lightning impulse withstand

test between windings and earth need to be stated by the purchaser.
5.1.3 Tapping

For DETC (De-energized tap changer), the preferred tapping ranges shall be ± 2,5 % with 3 tap

positions and ± 2 × 2,5 % with 5 tap positions. On special request ± 4 × 2,5 % with 9 tap positions can

be provided. Tapping ranges greater than ± 10 % or with more than 9 tap positions are unusual and

subject to specific agreement.

Tapping ranges outside the above definitions for DETC or any ranges for OLTC (On load tap changer)

shall be specified by agreement between manufacturer and purchaser.

The level of losses of this standard shall be compliant whatever the ranges and methods of tapping.

NOTE OLTC means also transformers equipped with tapping connections suitable for operation while

transformer is energised or on load for voltage adaptation purposes.
5.1.4 Connection designations for three phase transformers

Preferred connection designations (IEV [421-10-09]) shall be in accordance with clock notation 5 or

11 with Dyn, unless otherwise agreed between manufacturer and purchaser.
5.2 Energy Performance
5.2.1 General
5.2.1.1 Introduction

The tables below indicate the maximum level of losses for no-load losses and for load losses for

TIER1 and TIER2.

TIER1 has been applied since 1 July 2015 for the values of losses following Commission Regulation

(EU) No 548/2014 of 21 May 2014 and its amendment No 2019/1783 of 1 October 2019.

TIER2 shall be applied from 1 July 2021 for the values of losses following Commission Regulation

(EU) No 548/2014 of 21 May 2014 and its amendment No 2019/1783 of 1 October 2019.

Table 1 and 2 define load losses and no-load losses for one winding with Um ≤ 24 kV and the other

one with Um ≤ 3,6 kV. Additional corrections are defined for highest voltage, dual voltage or special

on load tapping, given in Table 3, 4, 5 and other clauses. Corrections factors in Table 3, 4, 5 are

cumulative.

During factory acceptance tests, the measured values of no-load and load losses shall not exceed

the respective maximum values determined with Table 1 and 2 and 6 and corrected by corrections

factor as stated above.
The reference conditions defined in EN 50708-1-1:2020 applies.

Other values of short-circuit impedance can be specified by the purchaser for particular system

service conditions, e.g. in the case of parallel operations in all tables of this clause.

The sound power levels are given in Tables 1 and 2. Transformers can be requested or offered with

sound power level L other than the listed values.

Unless otherwise agreed between manufacturer and purchaser the sound power level L given in

Tables 1 and 2 are considered for no load condition.

NOTE Loss levels and correction factors defined in 5.2.1.3 and 5.2.1.4 refer to two winding medium power

transformers. Loss levels for three windings medium power transformers are not defined due to lack of data at

the time of the publication of this standard.
EXAMPLE cumulative corrections:

In case of transformers having primary highest voltage for equipment Um = 36kV and secondary highest voltage

for equipment Um ≤ 3,6kV allowing 10 % on Pk and 15 % on P0 according to Table 3, and having dual voltage

on one winding allowing 10 % on Pk and 15 % on P0 according to Table 4.
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SIST EN 50708-2-1:2020
EN 50708-2-1:2020 (E)
The total corrections on Pk is 21 % (1,1x1,1–1) and P0 is 32,25 % (1,15x1,15–1)

5.2.1.2 Load losses and no-load losses for one winding with U ≤ 24 kV and the other one

with U ≤ 3,6 kV

The following tables are defined for step down or step up transformers with one winding with

U ≤ 24 kV and the other one with U ≤ 3,6 kV. Table 1 is for liquid immersed transformers and

m m
Table 2 for dry-type transformers.

Table 1 — Losses, short circuit impedance and sound power level for liquid immersed

transformers
Rated power TIER1 TIER1 TIER2 TIER2 Short-circuit Impedance
P P P
...

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