Requirements for generating plants to be connected in parallel with distribution networks - Part 1: Connection to a LV distribution network - Generating plants up to and including Type B

These standards provide technical requirements for the connection of generating plants up to and including Type A (-1-1)/ Type B (-1-2) which can be operated in parallel with a public LV distribution network. They are intended to be used as a technical reference for connection agreements between DNOs and electricity producers and to demonstrate compliance with COMMISSION REGULATION (EU) 2016/631 (Requirements for Generators).

Anforderungen für zum Parallelbetrieb mit einem Verteilnetz vorgesehene Erzeugungsanlagen - Teil 1: Anschluss an das Niederspannungsverteilnetz - Erzeugungsanlagen bis einschließlich Typ B

Exigences relatives aux centrales électriques destinées à être raccordées en parallèle à des réseaux de distribution - Partie 1: Raccordement à un réseau de distribution BT - Centrales électriques jusqu’au Type B inclus

Zahteve za vzporedno vezavo generatorskih postrojev z razdelilnim omrežjem - 1. del: Vezava z nizkonapetostnim razdelilnim omrežjem - Generatorski postroji do vključno tipa B

Ti standardi podajajo tehnične zahteve za povezovanje generatorskih postrojev do vključno tipa A (-1-1)/tipa B (-1-2), ki jih je mogoče upravljati vzporedno z javnim nizkonapetostnim razdelilnim omrežjem. Namen njihove uporabe je tehnična referenca za dogovore o priključku med upravljavci razdelilnih omrežij in proizvajalci električne energije ter izkazovanje skladnosti z UREDBO KOMISIJE (EU) 2016/631 (Zahteve za generatorje).

General Information

Status
Published
Publication Date
31-Jan-2019
Current Stage
6060 - Document made available
Due Date
01-Feb-2019
Completion Date
01-Feb-2019

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SLOVENSKI STANDARD
SIST EN 50549-1:2019
01-april-2019
Nadomešča:
SIST EN 50438:2014
SIST EN 50438:2014/IS1:2015
SIST-TS CLC/TS 50549-1:2015
Zahteve za vzporedno vezavo generatorskih postrojev z razdelilnim omrežjem - 1.
del: Vezava z nizkonapetostnim razdelilnim omrežjem - Generatorski postroji do
vključno tipa B

Requirements for generating plants to be connected in parallel with distribution networks

- Part 1: Connection to a LV distribution network - Generating plants up to and including

Type B
Anforderungen für zum Parallelbetrieb mit einem Verteilnetz vorgesehene
Erzeugungsanlagen - Teil 1: Anschluss an das Niederspannungsverteilnetz bis
einschließlich Typ B

Exigences relatives aux centrales électriques destinées à être raccordées en parallèle à

des réseaux de distribution - Partie 1: Raccordement à un réseau de distribution BT -

Centrales électriques jusqu’au Type B inclus
Ta slovenski standard je istoveten z: EN 50549-1:2019
ICS:
29.160.20 Generatorji Generators
29.240.01 Omrežja za prenos in Power transmission and
distribucijo električne energije distribution networks in
na splošno general
SIST EN 50549-1:2019 en,fr

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

---------------------- Page: 1 ----------------------
SIST EN 50549-1:2019
---------------------- Page: 2 ----------------------
SIST EN 50549-1:2019
EUROPEAN STANDARD EN 50549-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2019
ICS 29.160.20 Supersedes CLC/TS 50549-1:2015, EN 50438:2013, EN
50438:2013/IS1:2015
English Version
Requirements for generating plants to be connected in parallel
with distribution networks - Part 1: Connection to a LV
distribution network - Generating plants up to and including Type

Exigences relatives aux centrales électriques destinées à Anforderungen für zum Parallelbetrieb mit einem Verteilnetz

être raccordées en parallèle à des réseaux de distribution - vorgesehene Erzeugungsanlagen - Teil 1: Anschluss an

Partie 1: Raccordement à un réseau de distribution BT - das Niederspannungsverteilnetz bis einschließlich Typ B

Centrales électriques jusqu'au Type B inclus

This European Standard was approved by CENELEC on 2018-08-09. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, 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

© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 50549-1:2019 E
---------------------- Page: 3 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)
Contents Page

European foreword ................................................................................................................. 4

Introduction............................................................................................................................. 5

1 Scope ............................................................................................................................... 8

2 Normative references ....................................................................................................... 9

3 Terms and definitions ....................................................................................................... 9

3.1 General ................................................................................................................... 9

3.2 Plant, module and unit ........................................................................................... 11

3.3 Power .................................................................................................................... 14

3.4 Voltage .................................................................................................................. 15

3.5 Circuit theory ......................................................................................................... 16

3.6 Protection .............................................................................................................. 18

3.7 Control .................................................................................................................. 22

4 Requirements on generating plants ................................................................................ 23

4.1 General ................................................................................................................. 23

4.2 Connection scheme ............................................................................................... 24

4.3 Choice of switchgear ............................................................................................. 24

4.3.1 General ..................................................................................................... 24

4.3.2 Interface switch ......................................................................................... 24

4.4 Normal operating range ......................................................................................... 25

4.4.1 General ..................................................................................................... 25

4.4.2 Operating frequency range ........................................................................ 25

4.4.3 Minimal requirement for active power delivery at underfrequency .............. 26

4.4.4 Continuous operating voltage range .......................................................... 27

4.5 Immunity to disturbances ....................................................................................... 27

4.5.1 General ..................................................................................................... 27

4.5.2 Rate of change of frequency (ROCOF) immunity ....................................... 27

4.5.3 Under-voltage ride through (UVRT) ........................................................... 28

4.5.4 Over-voltage ride through (OVRT) ............................................................. 29

4.6 Active response to frequency deviation ................................................................. 30

4.6.1 Power response to overfrequency .............................................................. 30

4.6.2 Power response to underfrequency............................................................ 33

4.7 Power response to voltage changes ...................................................................... 36

4.7.1 General ..................................................................................................... 36

4.7.2 Voltage support by reactive power ............................................................. 36

4.7.3 Voltage related active power reduction ...................................................... 41

4.7.4 Short circuit current requirements on generating plants ............................. 41

4.8 EMC and power quality ......................................................................................... 42

4.9 Interface protection ............................................................................................... 43

4.9.1 General ..................................................................................................... 43

4.9.2 Void ........................................................................................................... 44

4.9.3 Requirements on voltage and frequency protection .................................... 45

4.9.4 Means to detect island situation ................................................................ 47

---------------------- Page: 4 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)

4.9.5 Digital input to the interface protection ...................................................... 48

4.10 Connection and starting to generate electrical power............................................. 48

4.10.1 General ..................................................................................................... 48

4.10.2 Automatic reconnection after tripping ......................................................... 48

4.10.3 Starting to generate electrical power ......................................................... 48

4.10.4 Synchronization ......................................................................................... 49

4.11 Ceasing and reduction of active power on set point ............................................... 49

4.11.1 Ceasing active power ................................................................................ 49

4.11.2 Reduction of active power on set point ...................................................... 49

4.12 Remote information exchange ............................................................................... 49

4.13 Requirements regarding single fault tolerance of interface protection system

and interface switch .............................................................................................. 50

Annex A (informative) Interconnection guidance ................................................................. 51

A.1 General .......................................................................................................................... 51

A.2 Network integration ........................................................................................................ 51

A.3 Clusters of single-phase generating units ....................................................................... 52

Annex B (informative) Void .................................................................................................. 53

Annex C (informative) Parameter Table .............................................................................. 54

Annex D (informative) List of national requirements applicable for generating plants ........... 59

Annex E (informative) Loss of Mains and overall power system security .............................. 61

Annex F (informative) Examples of protection strategies ...................................................... 62

F.1 Introduction .................................................................................................................... 62

F.1.1 General ................................................................................................................. 62

F.1.2 Generalities ........................................................................................................... 62

F.1.3 Detection of unwanted islands ............................................................................... 62

F.1.4 Problems with uncontrolled islanding in MV networks ............................................ 63

F.1.4.1 Safety ................................................................................................................... 63

F.1.4.2 Grid parameters .................................................................................................... 63

F.1.4.3 Reclosing operations ............................................................................................. 63

F.1.4.4 Protection of islands against overcurrents ............................................................. 63

F.1.4.5 Protection against phase to earth faults ................................................................. 63

F.2 Example strategy 1 ......................................................................................................... 64

F.3 Example strategy 2 ......................................................................................................... 67

Annex G (normative) Abbreviations ...................................................................................... 69

Annex H (informative) Relationship between this European standard and the

COMMISSION REGULATION (EU) 2016/631 ................................................................. 70

Bibliography .......................................................................................................................... 71

---------------------- Page: 5 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)
European foreword

This document (EN 50549-1:2019) has been prepared by CLC/TC 8X “System aspects of electrical

energy supply”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2019-08-01
implemented at national level by publication
of an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2022-02-01
conflicting with this document have to
be withdrawn
This document supersedes EN 50438:2013 and CLC/TS 50549-1:2015.

This European Standard relates to both the RfG European Network Code and current technical market

needs. Its purpose is to give detailed description of functions to be implemented in products.

This European Standard is also intended to serve as a technical reference for the definition of national

requirements where the RfG European Network Code requirements allow flexible implementation. The

specified requirements are solely technical requirements; economic issues regarding, e.g. the bearing

of cost are not in the scope of this document.

CLC/TC 8X plans future standardization work in order to ensure the compatibility of this European

Standard (EN) with the evolution of the legal framework.

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.

---------------------- Page: 6 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)
Introduction
Rationale for the content and structure of this document.
1. Foreword

This Explanatory Note explains the rationale behind the content and structure of prEN 50549-1 and

prEN 50549-2. Due to the unique relationship between COMMISSION REGULATION 2016/631 (RfG)

and the EN 50549 Series, and based on the comments received at the enquiry stage of prEN 50549-1

and prEN 50549-2, TC8X WG03 decided to draft this explanatory note in order to provide national

committees and the wider public with an understanding of these rationale.
2. Increased Scope of EN 50549 in relation to RfG

In the tradition of EN 50438, TC8X WG03 intended, in writing of prEN50549, to include all capabilities

of generating plants that are needed to operate these in parallel to distribution networks. This includes

issues necessary for a stable distribution network management as well as the management of the

interconnected system. As RfG is focused on the interconnected system, it is logical that, taking into

account further needs for distribution network management, further aspects are included.

3. Introduction of “Responsible party”

During the national implementation process of COMMISSION REGULATION (EU) 2016/631, different

types of responsible parties play a role in the refinement of the non-exhaustive requirements. In each

member country, the National Regulatory Authority approves this national implementation. Depending

on the national regulatory framework, this might result in a variety of documents: national laws,

decrees or regulations, technical specifications, or requirements of transmission and distribution

system operators. Therefore, as explained in the scope, EN 50549-1 and EN 50549-2 refer to the

“responsible party” where requirements have to be defined by an actor other than the DSO. However

when a generating plant is built and connected to the distribution network, typically the distribution

system operator provides the plant developer all the technical requirements to be fulfilled.

4. Use of terms

Terms and definitions are selected to achieve consistency with EN 60050, IEV (cf.

www.electropedia.org) and CENELEC terminology, recognizing that terms in COMMISSION

REGULATION (EU) 2016/631 may deviate.
5. Additional requirements for distribution system management

The following requirements are stated in EN 50549 for distribution system management reasons,

which might not be required in RfG or if required in RfG, are not required for type A. As Directive

714/2009 8(7) limits the scope of RfG to issues effecting the cross border trade of electricity,

requirements included solely for the need of distribution system management are considered beyond

the scope of RfG.
– Connection scheme and Coordination of switch gear,
– Voltage operating range,
– Reactive power capability and control modes,
– Voltage related active power reduction,
– Interface protection including the detection of island situations,
– Connection and reconnection to the grid,
– Generation curtailment,
– Remote information exchange,
---------------------- Page: 7 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)
6. Additional requirements for stability of the interconnected system

Additionally, requirements relevant for the stability of the interconnected systems are included in case

of over voltage ride through (OVRT) as this is not dealt with in RfG. Due to the long duration of RfG

development and the fast development of decentralised generation in Europe robustness to voltage

swells is considered to be of high importance, but apparently could not be included into RfG.

As electrical energy storage system (EESS), are excluded from the scope of RfG, but are included in

the scope of the EN 50549 Series, EN 50549 also includes the further requirement of active power

frequency response to under frequency (LFSM-U) to electrical energy storage systems. This

requirement is considered of great importance in view of the expected fast increase of electrical

energy storage for the next years and is considered not to affect the cost of electrical energy storage

systems if considered during their design.
7. Details on the operation of the LFSM-O

During the enquiry stage, some comments reported that certain details in the chapter regarding the

operation of the LFSM-O (e.g. intentional delay, operation with deactivation threshold) were violating

the RfG. These topics have been further evaluated consulting the European Stakeholder Committee

(ESC-GC) and TC8X WG03 could not conclude in the same way. The fact that these operations are

not foreseen in the RfG is considered not sufficient to state any violation. Therefore these details are

kept with additional information on their use.
8. Implementation of UVRT and LFSM-U to avoid legal conflict with RfG

Under Voltage Ride Through (UVRT) requirements are defined in RfG for modules type B, type C and

type D. There is no mentioning of this topic for type A modules.

Nevertheless UVRT is seen as an important requirement in some member states even for small

generation modules like type A.

From a legal point of view there are two contradicting opinions on whether it is allowed or forbidden to

require UVRT for type A modules.

– Opinion 1: It can be required because the topic is not dealt with for type A modules.

– Option 2: It cannot be required because the topic UVRT is dealt within the RfG. Not mentioning

UVRT for type A in RfG therefore means that it cannot be required for type A modules.

As long as there is no clarification on this legal issue Cenelec does not have the possibility to require

UVRT for type A modules. This is the reason why in EN 50549-1 and 50549-2 the UVRT

functionalities for type A generating plants are not defined as requirements (shall) but as a

recommendation (should).

This same explanation can be applied to the requirements regarding Limited Frequency Sensitive

Mode - Underfrequency (LFSM-U). In RfG, this LFSM-U is solely defined for type C and type D

modules. In EN50549 , LFSM-U is defined as a recommendation (should) for generating modules of

type A and type B. The sole exception is electrical energy storage systems having a requirement

(shall) but these systems are not within the scope of the RfG.
9. Annex H - Relationship between this European standard and the COMMISSION
REGULATION (EU) 2016/631.

Manufacturers of generating units and plants shall comply with all relevant EU Directives and

Regulations. For the specific function of connecting the generating plant with the electric system the

reference regulation is COMMISSION REGULATION (EU) 2016/631 (NC RfG).

Since the EN 50549-1 and -2 are covering all technical requirements for type A and type B generating

units, modules and plants, it is considered helpful to provide the information which clause of the

standard supports which article of the RfG in a structured informative annex within the standard.

For other EU Directives and Regulations (e.g. LVD, MD or GAR) it is a formal task given to CCMC to

include such an informative Annex ZZ based on a standardization request from the EU. It is finally

reviewed by the new approach consultant (NAC) for the relevant Directive or Regulation, prior to the

listing of the standard in the official journal of the EU (OJEU) providing then “presumption of

---------------------- Page: 8 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)

conformity”. This means that if a product is compliant with the standard, the Directive or Regulations is

fulfilled too.

CLC TC 8X is fully aware, that this official procedure is not included in the RfG. Therefore CLC TC 8X

WG3 drafted Annex H. In Annex H the relationship between the clauses and the articles is shown. It is

considered, that generating plants compliant with the clauses of the standards are also compliant with

the articles in the RfG. Of course, this does not provide “presumption of conformity” as a listed

standard in the OJEU would provide. Nevertheless it will be helpful for the industry when performing

the conformity assessment against RfG.
---------------------- Page: 9 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)
1 Scope

This document specifies the technical requirements for the protection functions and the operational

capabilities for generating plants, intended to operate in parallel with LV distribution networks.

For practical reasons this document refers to the responsible party where requirements have to be

defined by an actor other than the DSO e.g. TSO, member state, regulatory authorities according to

the legal framework. Typically the DSO will inform the producer about these requirements.

NOTE 1 This includes European network codes and their national implementation, as well as additional

national regulations.

NOTE 2 Additional national requirements especially for the connection to the distribution network and the

operation of the generating plant may apply.

The requirements of this European Standard apply, irrespective of the kind of energy source and

irrespective of the presence of loads in the producer’s network, to generating plants, generating

modules, electrical machinery and electronic equipment that meet all of the following conditions:

— converting any energy source into AC electricity;

— generating modules capacity of type B or smaller according to COMMISSION REGULATION (EU)

2016/631 while considering national implementation for the decision regarding power limits

between A and B types and B and C types;
— connected to and operated in parallel with an AC LV distribution network.

NOTE 3 Generating plants connected to a MV distribution network fall into the scope of EN 50549–2.

NOTE 4 Electrical energy storage systems (EESS) in meeting the conditions above are included

If generating modules of different type (A or B) are combined in one plant, different requirements apply

for the different modules based on the type of each module.

EXAMPLE: If a generating plant consists of multiple generating modules (see 3.2.1), according to

COMMISSION REGLUATION (EU) 2016/631 the situation might occur, that some generating modules

are of type A and some are of type B.

Unless specified otherwise by the DSO and the responsible party, generating plants connected to a

medium voltage distribution network with a maximum apparent power up to 150 kVA can comply with

this European Standard as alternative to the requirements of EN 50549-2. A different threshold may

be defined by the DSO and the responsible party.

This document recognizes the existence of specific technical requirements (e.g. grid codes) of the

DSO or another responsible party within a member state and these must be complied with.

Excluded from the scope are:
• the selection and evaluation of the point of connection;

• power system impact assessment e.g. assessment of effects on power quality, local voltage

increase, impact on line protections operation;

• connection assessment, the set of technical verifications made as part of the planning of the

connection;

• island operation of generating plants, both intentional and unintentional, where no part of the

distribution network is involved;

• four-quadrant rectifier of drives feeding breaking energy back into the distribution network for

limited duration with no internal source of primary energy;

• uninterruptible power supply with duration of parallel operation limited to 100 ms;

---------------------- Page: 10 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)

NOTE 5 Parallel operation due to maintenance of uninterruptible power supply units is not seen as part of

normal UPS operation and therefore not considered in this document.

• requirements for the safety of personnel as they are already adequately covered by existing

European Standards.
• the connection of a generating unit, module or plant into a DC network
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 50549-2, Requirements for generating plants to be connected in parallel with distribution networks

- Part 2: Connection to a MV distribution network - Generating plants up to and including Type B

EN 60255-127, Measuring relays and protection equipment — Part 127: Functional requirements for

over/under voltage protection (IEC 60255-127)

EN 61000-4-30, Electromagnetic compatibility (EMC) — Part 4-30: Testing and measurement

techniques — Power quality measurement methods (IEC 61000-4-30)

HD 60364-1, Low-voltage electrical installations — Part 1: Fundamental principles, assessment of

general characteristics, definitions (IEC 60364-1)

HD 60364-5-551, Low-voltage electrical installations — Part 5-55: Selection and erection of electrical

equipment — Other equipment — Clause 551: Low-voltage generating sets (IEC 60364-5-551)

3 Terms and definitions
For the purposes of this document, the following terms and definitions 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

Note Terms and definitions are selected to achieve consistency with IEV (cf. www.electropedia.org) and

CENELEC terminology, recognizing that terms in COMMISSION REGULATION (EU) 2016/631 may deviate.

3.1 General
3.1.1
distribution network

AC electrical network, including closed distribution networks, for the distribution of electrical power

from and to third parties connected to it, to and from a transmission or another distribution network, for

which a DSO is responsible
Note 1 to entry: A distribution network does not include the producer’s network.
---------------------- Page: 11 ----------------------
SIST EN 50549-1:2019
EN 50549-1:2019 (E)
3.1.2
closed distribution network

system which distributes electricity within an industrial, commercial or shared services site, that is

geographically confined, and does not supply households customers (without excluding the option of a

small number of households served by the system that have an employment or similar associations

with the owner of the system)

Note 1 to entry: A closed distribution network will either be used to integrate the production processes of the

network users for specific or technical reasons or distribute electricity primarily to the operator of the closed

distribution network or his related undertakings.
[SOURCE: Directive 2009/72/EC, article 28, modified]
3.1.3
distribution system operator
DSO

natural or legal person responsible for the distribution of electrical power to final customers and for

operati
...

SLOVENSKI STANDARD
SIST EN 50549-1:2019
01-april-2019
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SIST EN 50438:2014
SIST EN 50438:2014/IS1:2015
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Requirements for generating plants to be connected in parallel with distribution networks

- Part 1-1: Connection to a LV distribution network – Generating plants up to and

including Type A
Anforderungen für zum Parallelbetrieb mit einem Verteilnetz vorgesehene
Erzeugungsanlagen - Teil 1: Anschluss an das Niederspannungsverteilnetz bis
einschließlich Typ B

Exigences relatives aux centrales électriques destinées à être raccordées en parallèle à

des réseaux de distribution - Partie 1: Raccordement à un réseau de distribution BT -

Centrales électriques jusqu’au Type B inclus
Ta slovenski standard je istoveten z: EN 50549-1:2019
ICS:
29.160.20 Generatorji Generators
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
SIST EN 50549-1:2019 en,fr

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

---------------------- Page: 1 ----------------------
SIST EN 50549-1:2019
---------------------- Page: 2 ----------------------
SIST EN 50549-1:2019
EUROPEAN STANDARD EN 50549-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2019
ICS 29.160.20 Supersedes CLC/TS 50549-1:2015, EN 50438:2013, EN
50438:2013/IS1:2015
English Version
Requirements for generating plants to be connected in parallel
with distribution networks - Part 1: Connection to a LV
distribution network - Generating plants up to and including Type

Exigences relatives aux centrales électriques destinées à Anforderungen für zum Parallelbetrieb mit einem Verteilnetz

être raccordées en parallèle à des réseaux de distribution - vorgesehene Erzeugungsanlagen - Teil 1: Anschluss an

Partie 1: Raccordement à un réseau de distribution BT - das Niederspannungsverteilnetz bis einschließlich Typ B

Centrales électriques jusqu'au Type B inclus

This European Standard was approved by CENELEC on 2018-08-09. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, 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
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© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 50549-1:2019 E
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SIST EN 50549-1:2019
EN 50549-1:2019 (E)
Contents Page

European foreword ................................................................................................................. 4

Introduction............................................................................................................................. 5

1 Scope ............................................................................................................................... 8

2 Normative references ....................................................................................................... 9

3 Terms and definitions ....................................................................................................... 9

3.1 General ................................................................................................................... 9

3.2 Plant, module and unit ........................................................................................... 11

3.3 Power .................................................................................................................... 14

3.4 Voltage .................................................................................................................. 15

3.5 Circuit theory ......................................................................................................... 16

3.6 Protection .............................................................................................................. 18

3.7 Control .................................................................................................................. 22

4 Requirements on generating plants ................................................................................ 23

4.1 General ................................................................................................................. 23

4.2 Connection scheme ............................................................................................... 24

4.3 Choice of switchgear ............................................................................................. 24

4.3.1 General ..................................................................................................... 24

4.3.2 Interface switch ......................................................................................... 24

4.4 Normal operating range ......................................................................................... 25

4.4.1 General ..................................................................................................... 25

4.4.2 Operating frequency range ........................................................................ 25

4.4.3 Minimal requirement for active power delivery at underfrequency .............. 26

4.4.4 Continuous operating voltage range .......................................................... 27

4.5 Immunity to disturbances ....................................................................................... 27

4.5.1 General ..................................................................................................... 27

4.5.2 Rate of change of frequency (ROCOF) immunity ....................................... 27

4.5.3 Under-voltage ride through (UVRT) ........................................................... 28

4.5.4 Over-voltage ride through (OVRT) ............................................................. 29

4.6 Active response to frequency deviation ................................................................. 30

4.6.1 Power response to overfrequency .............................................................. 30

4.6.2 Power response to underfrequency............................................................ 33

4.7 Power response to voltage changes ...................................................................... 36

4.7.1 General ..................................................................................................... 36

4.7.2 Voltage support by reactive power ............................................................. 36

4.7.3 Voltage related active power reduction ...................................................... 41

4.7.4 Short circuit current requirements on generating plants ............................. 41

4.8 EMC and power quality ......................................................................................... 42

4.9 Interface protection ............................................................................................... 43

4.9.1 General ..................................................................................................... 43

4.9.2 Void ........................................................................................................... 44

4.9.3 Requirements on voltage and frequency protection .................................... 45

4.9.4 Means to detect island situation ................................................................ 47

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4.9.5 Digital input to the interface protection ...................................................... 48

4.10 Connection and starting to generate electrical power............................................. 48

4.10.1 General ..................................................................................................... 48

4.10.2 Automatic reconnection after tripping ......................................................... 48

4.10.3 Starting to generate electrical power ......................................................... 48

4.10.4 Synchronization ......................................................................................... 49

4.11 Ceasing and reduction of active power on set point ............................................... 49

4.11.1 Ceasing active power ................................................................................ 49

4.11.2 Reduction of active power on set point ...................................................... 49

4.12 Remote information exchange ............................................................................... 49

4.13 Requirements regarding single fault tolerance of interface protection system

and interface switch .............................................................................................. 50

Annex A (informative) Interconnection guidance ................................................................. 51

A.1 General .......................................................................................................................... 51

A.2 Network integration ........................................................................................................ 51

A.3 Clusters of single-phase generating units ....................................................................... 52

Annex B (informative) Void .................................................................................................. 53

Annex C (informative) Parameter Table .............................................................................. 54

Annex D (informative) List of national requirements applicable for generating plants ........... 59

Annex E (informative) Loss of Mains and overall power system security .............................. 61

Annex F (informative) Examples of protection strategies ...................................................... 62

F.1 Introduction .................................................................................................................... 62

F.1.1 General ................................................................................................................. 62

F.1.2 Generalities ........................................................................................................... 62

F.1.3 Detection of unwanted islands ............................................................................... 62

F.1.4 Problems with uncontrolled islanding in MV networks ............................................ 63

F.1.4.1 Safety ................................................................................................................... 63

F.1.4.2 Grid parameters .................................................................................................... 63

F.1.4.3 Reclosing operations ............................................................................................. 63

F.1.4.4 Protection of islands against overcurrents ............................................................. 63

F.1.4.5 Protection against phase to earth faults ................................................................. 63

F.2 Example strategy 1 ......................................................................................................... 64

F.3 Example strategy 2 ......................................................................................................... 67

Annex G (normative) Abbreviations ...................................................................................... 69

Annex H (informative) Relationship between this European standard and the

COMMISSION REGULATION (EU) 2016/631 ................................................................. 70

Bibliography .......................................................................................................................... 71

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European foreword

This document (EN 50549-1:2019) has been prepared by CLC/TC 8X “System aspects of electrical

energy supply”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2019-08-01
implemented at national level by publication
of an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2022-02-01
conflicting with this document have to
be withdrawn
This document supersedes EN 50438:2013 and CLC/TS 50549-1:2015.

This European Standard relates to both the RfG European Network Code and current technical market

needs. Its purpose is to give detailed description of functions to be implemented in products.

This European Standard is also intended to serve as a technical reference for the definition of national

requirements where the RfG European Network Code requirements allow flexible implementation. The

specified requirements are solely technical requirements; economic issues regarding, e.g. the bearing

of cost are not in the scope of this document.

CLC/TC 8X plans future standardization work in order to ensure the compatibility of this European

Standard (EN) with the evolution of the legal framework.

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.

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Introduction
Rationale for the content and structure of this document.
1. Foreword

This Explanatory Note explains the rationale behind the content and structure of prEN 50549-1 and

prEN 50549-2. Due to the unique relationship between COMMISSION REGULATION 2016/631 (RfG)

and the EN 50549 Series, and based on the comments received at the enquiry stage of prEN 50549-1

and prEN 50549-2, TC8X WG03 decided to draft this explanatory note in order to provide national

committees and the wider public with an understanding of these rationale.
2. Increased Scope of EN 50549 in relation to RfG

In the tradition of EN 50438, TC8X WG03 intended, in writing of prEN50549, to include all capabilities

of generating plants that are needed to operate these in parallel to distribution networks. This includes

issues necessary for a stable distribution network management as well as the management of the

interconnected system. As RfG is focused on the interconnected system, it is logical that, taking into

account further needs for distribution network management, further aspects are included.

3. Introduction of “Responsible party”

During the national implementation process of COMMISSION REGULATION (EU) 2016/631, different

types of responsible parties play a role in the refinement of the non-exhaustive requirements. In each

member country, the National Regulatory Authority approves this national implementation. Depending

on the national regulatory framework, this might result in a variety of documents: national laws,

decrees or regulations, technical specifications, or requirements of transmission and distribution

system operators. Therefore, as explained in the scope, EN 50549-1 and EN 50549-2 refer to the

“responsible party” where requirements have to be defined by an actor other than the DSO. However

when a generating plant is built and connected to the distribution network, typically the distribution

system operator provides the plant developer all the technical requirements to be fulfilled.

4. Use of terms

Terms and definitions are selected to achieve consistency with EN 60050, IEV (cf.

www.electropedia.org) and CENELEC terminology, recognizing that terms in COMMISSION

REGULATION (EU) 2016/631 may deviate.
5. Additional requirements for distribution system management

The following requirements are stated in EN 50549 for distribution system management reasons,

which might not be required in RfG or if required in RfG, are not required for type A. As Directive

714/2009 8(7) limits the scope of RfG to issues effecting the cross border trade of electricity,

requirements included solely for the need of distribution system management are considered beyond

the scope of RfG.
– Connection scheme and Coordination of switch gear,
– Voltage operating range,
– Reactive power capability and control modes,
– Voltage related active power reduction,
– Interface protection including the detection of island situations,
– Connection and reconnection to the grid,
– Generation curtailment,
– Remote information exchange,
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6. Additional requirements for stability of the interconnected system

Additionally, requirements relevant for the stability of the interconnected systems are included in case

of over voltage ride through (OVRT) as this is not dealt with in RfG. Due to the long duration of RfG

development and the fast development of decentralised generation in Europe robustness to voltage

swells is considered to be of high importance, but apparently could not be included into RfG.

As electrical energy storage system (EESS), are excluded from the scope of RfG, but are included in

the scope of the EN 50549 Series, EN 50549 also includes the further requirement of active power

frequency response to under frequency (LFSM-U) to electrical energy storage systems. This

requirement is considered of great importance in view of the expected fast increase of electrical

energy storage for the next years and is considered not to affect the cost of electrical energy storage

systems if considered during their design.
7. Details on the operation of the LFSM-O

During the enquiry stage, some comments reported that certain details in the chapter regarding the

operation of the LFSM-O (e.g. intentional delay, operation with deactivation threshold) were violating

the RfG. These topics have been further evaluated consulting the European Stakeholder Committee

(ESC-GC) and TC8X WG03 could not conclude in the same way. The fact that these operations are

not foreseen in the RfG is considered not sufficient to state any violation. Therefore these details are

kept with additional information on their use.
8. Implementation of UVRT and LFSM-U to avoid legal conflict with RfG

Under Voltage Ride Through (UVRT) requirements are defined in RfG for modules type B, type C and

type D. There is no mentioning of this topic for type A modules.

Nevertheless UVRT is seen as an important requirement in some member states even for small

generation modules like type A.

From a legal point of view there are two contradicting opinions on whether it is allowed or forbidden to

require UVRT for type A modules.

– Opinion 1: It can be required because the topic is not dealt with for type A modules.

– Option 2: It cannot be required because the topic UVRT is dealt within the RfG. Not mentioning

UVRT for type A in RfG therefore means that it cannot be required for type A modules.

As long as there is no clarification on this legal issue Cenelec does not have the possibility to require

UVRT for type A modules. This is the reason why in EN 50549-1 and 50549-2 the UVRT

functionalities for type A generating plants are not defined as requirements (shall) but as a

recommendation (should).

This same explanation can be applied to the requirements regarding Limited Frequency Sensitive

Mode - Underfrequency (LFSM-U). In RfG, this LFSM-U is solely defined for type C and type D

modules. In EN50549 , LFSM-U is defined as a recommendation (should) for generating modules of

type A and type B. The sole exception is electrical energy storage systems having a requirement

(shall) but these systems are not within the scope of the RfG.
9. Annex H - Relationship between this European standard and the COMMISSION
REGULATION (EU) 2016/631.

Manufacturers of generating units and plants shall comply with all relevant EU Directives and

Regulations. For the specific function of connecting the generating plant with the electric system the

reference regulation is COMMISSION REGULATION (EU) 2016/631 (NC RfG).

Since the EN 50549-1 and -2 are covering all technical requirements for type A and type B generating

units, modules and plants, it is considered helpful to provide the information which clause of the

standard supports which article of the RfG in a structured informative annex within the standard.

For other EU Directives and Regulations (e.g. LVD, MD or GAR) it is a formal task given to CCMC to

include such an informative Annex ZZ based on a standardization request from the EU. It is finally

reviewed by the new approach consultant (NAC) for the relevant Directive or Regulation, prior to the

listing of the standard in the official journal of the EU (OJEU) providing then “presumption of

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conformity”. This means that if a product is compliant with the standard, the Directive or Regulations is

fulfilled too.

CLC TC 8X is fully aware, that this official procedure is not included in the RfG. Therefore CLC TC 8X

WG3 drafted Annex H. In Annex H the relationship between the clauses and the articles is shown. It is

considered, that generating plants compliant with the clauses of the standards are also compliant with

the articles in the RfG. Of course, this does not provide “presumption of conformity” as a listed

standard in the OJEU would provide. Nevertheless it will be helpful for the industry when performing

the conformity assessment against RfG.
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1 Scope

This document specifies the technical requirements for the protection functions and the operational

capabilities for generating plants, intended to operate in parallel with LV distribution networks.

For practical reasons this document refers to the responsible party where requirements have to be

defined by an actor other than the DSO e.g. TSO, member state, regulatory authorities according to

the legal framework. Typically the DSO will inform the producer about these requirements.

NOTE 1 This includes European network codes and their national implementation, as well as additional

national regulations.

NOTE 2 Additional national requirements especially for the connection to the distribution network and the

operation of the generating plant may apply.

The requirements of this European Standard apply, irrespective of the kind of energy source and

irrespective of the presence of loads in the producer’s network, to generating plants, generating

modules, electrical machinery and electronic equipment that meet all of the following conditions:

— converting any energy source into AC electricity;

— generating modules capacity of type B or smaller according to COMMISSION REGULATION (EU)

2016/631 while considering national implementation for the decision regarding power limits

between A and B types and B and C types;
— connected to and operated in parallel with an AC LV distribution network.

NOTE 3 Generating plants connected to a MV distribution network fall into the scope of EN 50549–2.

NOTE 4 Electrical energy storage systems (EESS) in meeting the conditions above are included

If generating modules of different type (A or B) are combined in one plant, different requirements apply

for the different modules based on the type of each module.

EXAMPLE: If a generating plant consists of multiple generating modules (see 3.2.1), according to

COMMISSION REGLUATION (EU) 2016/631 the situation might occur, that some generating modules

are of type A and some are of type B.

Unless specified otherwise by the DSO and the responsible party, generating plants connected to a

medium voltage distribution network with a maximum apparent power up to 150 kVA can comply with

this European Standard as alternative to the requirements of EN 50549-2. A different threshold may

be defined by the DSO and the responsible party.

This document recognizes the existence of specific technical requirements (e.g. grid codes) of the

DSO or another responsible party within a member state and these must be complied with.

Excluded from the scope are:
• the selection and evaluation of the point of connection;

• power system impact assessment e.g. assessment of effects on power quality, local voltage

increase, impact on line protections operation;

• connection assessment, the set of technical verifications made as part of the planning of the

connection;

• island operation of generating plants, both intentional and unintentional, where no part of the

distribution network is involved;

• four-quadrant rectifier of drives feeding breaking energy back into the distribution network for

limited duration with no internal source of primary energy;

• uninterruptible power supply with duration of parallel operation limited to 100 ms;

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NOTE 5 Parallel operation due to maintenance of uninterruptible power supply units is not seen as part of

normal UPS operation and therefore not considered in this document.

• requirements for the safety of personnel as they are already adequately covered by existing

European Standards.
• the connection of a generating unit, module or plant into a DC network
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 50549-2, Requirements for generating plants to be connected in parallel with distribution networks

- Part 2: Connection to a MV distribution network - Generating plants up to and including Type B

EN 60255-127, Measuring relays and protection equipment — Part 127: Functional requirements for

over/under voltage protection (IEC 60255-127)

EN 61000-4-30, Electromagnetic compatibility (EMC) — Part 4-30: Testing and measurement

techniques — Power quality measurement methods (IEC 61000-4-30)

HD 60364-1, Low-voltage electrical installations — Part 1: Fundamental principles, assessment of

general characteristics, definitions (IEC 60364-1)

HD 60364-5-551, Low-voltage electrical installations — Part 5-55: Selection and erection of electrical

equipment — Other equipment — Clause 551: Low-voltage generating sets (IEC 60364-5-551)

3 Terms and definitions
For the purposes of this document, the following terms and definitions 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

Note Terms and definitions are selected to achieve consistency with IEV (cf. www.electropedia.org) and

CENELEC terminology, recognizing that terms in COMMISSION REGULATION (EU) 2016/631 may deviate.

3.1 General
3.1.1
distribution network

AC electrical network, including closed distribution networks, for the distribution of electrical power

from and to third parties connected to it, to and from a transmission or another distribution network, for

which a DSO is responsible
Note 1 to entry: A distribution network does not include the producer’s network.
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3.1.2
closed distribution network

system which distributes electricity within an industrial, commercial or shared services site, that is

geographically confined, and does not supply households customers (without excluding the option of a

small number of households served by the system that have an employment or similar associations

with the owner of the system)

Note 1 to entry: A closed distribution network will either be used to integrate the production processes of the

network users for specific or technical reasons or distribute electricity primarily to the operator of the closed

distribution network or his related undertakings.
[SOURCE: Directive 2009/72/EC, article 28, modified]
3.1.3
distribution system operator
DSO

natural or legal person responsible for the distribution of electrical power to final cust

...

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