EN IEC 62933-1:2024
(Main)Electrical energy storage (EES) systems - Part 1: Vocabulary
Electrical energy storage (EES) systems - Part 1: Vocabulary
IEC 62933-1:2024 defines terms applicable to electrical energy storage (EES) systems including terms necessary for the definition of unit parameters, test methods, planning, installation, operation, environmental and safety issues. This terminology document is applicable to grid-connected systems able to extract electrical energy from an electric power system, store energy internally, and provide electrical energy to an electric power system. The step for charging and discharging an EES system can comprise an energy conversion. This second edition cancels and replaces the first edition published in 2018. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) addition (with revision) of the entries developed during the edition 1 stability period and, therefore, included only in other IEC 62933 parts; b) addition of the entries developed during the edition 1 stability period and published in this document for the first time; c) complete revision of the entries already present in edition 1.
Elektrische Energiespeichersysteme (EES-Systeme) - Teil 1: Terminologie
Systèmes de stockage de l'énergie électrique (EES) - Partie 1 : Vocabulaire
L’IEC 62933-1:2024 définit les termes applicables aux systèmes de stockage de l’énergie électrique (EES - electrical energy storage), y compris les termes nécessaires à la définition des paramètres unitaires, des méthodes d’essai, de la planification, de l’installation, du fonctionnement et des problèmes environnementaux et de sécurité. Le présent document terminologique est applicable aux systèmes connectés au réseau capables d’extraire l’énergie électrique d’un réseau d’alimentation électrique, de stocker l’énergie en interne et de fournir de l’énergie électrique à un réseau d’alimentation électrique. La phase de charge et de décharge d’un système EES peut inclure une conversion d’énergie. Cette seconde édition annule et remplace la première édition parue en 2018. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) ajout (avec révision) des articles élaborés pendant la période de stabilité de l’édition 1 et, par conséquent, inclus seulement dans d’autres parties de l’IEC 62933; b) ajout des articles élaborés pendant la période de stabilité de l’édition 1 et publiés dans le présent document pour la première fois; c) révision complète des articles déjà présents dans l’édition 1.
Električne naprave za shranjevanje energije (EES) - 1. del: Slovar (IEC 62933-1:2024)
V standardu IEC 62933-1:2024 so opredeljeni izrazi, ki se uporabljajo za električne naprave za shranjevanje energije (EES), vključno z izrazi, potrebnimi za opredelitev parametrov enote, preskusnih metod, načrtovanja, namestitve, delovanja ter okoljskih in varnostnih vidikov.
Ta terminološki dokument se uporablja za sisteme z omrežnim napajanjem, ki lahko pridobivajo električno energijo iz sistema električnega napajanja, jo shranjujejo v notranjosti in dovajajo sistemu električnega napajanja. Polnjenje in praznjenje električne naprave za shranjevanje energije lahko vključuje tudi pretvorbo energije.
Druga izdaja razveljavlja in nadomešča prvo izdajo, objavljeno leta 2018. Ta izdaja je tehnično popravljena izdaja.
Ta izdaja v primerjavi s prejšnjo vključuje naslednje pomembne tehnične spremembe:
a) dodani (in pregledani) so bili vnosi, ustvarjeni v obdobju stabilnosti prve izdaje in vključeni le v drugih delih standarda IEC 62933;
b) dodani so bili vnosi, ustvarjeni v obdobju stabilnosti prve izdaje, ki so v tem dokumentu prvič objavljeni;
c) vnosi, ki so že bili objavljeni v prvi izdaji, so bili v celoti pregledani.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2024
Električne naprave za shranjevanje energije (EES) - 1. del: Slovar (IEC 62933-
1:2024)
Electrical energy storage (EES) systems - Part 1: Vocabulary (IEC 62933-1:2024)
Elektrische Energiespeichersysteme (EES-Systeme) - Teil 1: Terminologie (IEC 62933-
1:2024)
Systèmes de stockage de l'énergie électrique (EES) - Partie 1: Vocabulaire (IEC 62933-
1:2024)
Ta slovenski standard je istoveten z: EN IEC 62933-1:2024
ICS:
01.040.27 Prenos energije in toplote Energy and heat transfer
(Slovarji) engineering (Vocabularies)
27.010 Prenos energije in toplote na Energy and heat transfer
splošno engineering in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 62933-1
NORME EUROPÉENNE
EUROPÄISCHE NORM June 2024
ICS 01.040.17 Supersedes EN IEC 62933-1:2018
English Version
Electrical energy storage (EES) systems - Part 1: Vocabulary
(IEC 62933-1:2024)
Systèmes de stockage de l'énergie électrique (EES) - Partie Elektrische Energiespeichersysteme (EES-Systeme) - Teil
1 : Vocabulaire 1: Terminologie
(IEC 62933-1:2024) (IEC 62933-1:2024)
This European Standard was approved by CENELEC on 2024-06-19. 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,
Türkiye 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
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62933-1:2024 E
European foreword
The text of document 120/358/FDIS, future edition 2 of IEC 62933-1, prepared by IEC/TC 120
"Electrical Energy Storage (EES) systems" was submitted to the IEC-CENELEC parallel vote and
approved by CENELEC as EN IEC 62933-1:2024.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-03-19
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-06-19
document have to be withdrawn
This document supersedes EN IEC 62933-1:2018 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.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62933-1:2024 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60027 series NOTE Approved as EN 60027 series
IEC 61165:2006 NOTE Approved as EN 61165:2006 (not modified)
IEC 61427-2:2015 NOTE Approved as EN 61427-2:2015 (not modified)
IEC 61850-4:2011 NOTE Approved as EN 61850-4:2011 (not modified)
IEC 61850-4:2011/A1:2020 NOTE Approved as EN 61850-4:2011/A1:2020 (not modified)
IEC 61987-1:2006 NOTE Approved as EN 61987-1:2007 (not modified)
IEC 62381:2012 NOTE Approved as EN 62381:2012 (not modified)
IEC 62443-3-3:2013 NOTE Approved as EN IEC 62443-3-3:2019 (not modified)
IEC 62477-1:2012 NOTE Approved as EN 62477-1:2012 (not modified) +A11:2014
IEC 62668-1:2019 NOTE Approved as EN IEC 62668-1:2019 (not modified)
IEC 62680 series NOTE Approved as EN IEC 62680 series
IEC 62928:2017 NOTE Approved as EN IEC 62928:2018 (not modified)
IEC 62932-1:2020 NOTE Approved as EN IEC 62932-1:2020 (not modified)
IEC 62934:2021 NOTE Approved as EN IEC 62934:2021 (not modified)
ISO 14050:2020 NOTE Approved as EN ISO 14050:2020 (not modified)
IEC 62933-1 ®
Edition 2.0 2024-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical energy storage (EES) systems –
Part 1: Vocabulary
Systèmes de stockage de l'énergie électrique (EES) –
Partie 1 : Vocabulaire
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 01.040.17 ISBN 978-2-8322-8797-2
– 2 – IEC 62933-1:2024 © IEC 2024
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions for EES systems classification . 6
3.1 Fundamental concepts for EES systems classification . 6
3.2 EES systems classification . 7
3.3 EES systems long-duration application . 9
3.4 EES systems short-duration application . 10
3.5 EES systems hybrid and emergency application . 12
4 Terms and definitions for EES systems specification . 12
4.1 Fundamental concepts for EES systems specification . 12
4.2 EES system duty cycles . 15
4.3 EES system primary POC . 17
4.4 EES system auxiliary POC . 24
4.5 EES system service life . 25
4.6 EES system energy efficiency . 27
4.7 EES system step response performances . 29
5 Terms and definitions for EES systems planning and installation . 32
5.1 Fundamental concepts for EES systems planning and installation . 32
5.2 EES system primary subsystem . 33
5.3 EES system auxiliary subsystem . 34
5.4 EES system control subsystem . 35
6 Terms and definitions for EES systems operation . 36
6.1 EES system operating state . 36
6.2 EES system operating signals . 37
6.3 EES system operating procedure . 40
6.4 EES system operating mode . 40
7 Terms and definitions for EES systems' environmental and safety issues . 41
7.1 EES system environmental issues . 41
7.2 EES system safety . 42
Annex A (informative) Index . 45
A.1 Terms index . 45
A.2 Abbreviated terms index . 45
Bibliography . 51
Figure 1 – Illustrative example of EES system energy storage capacities relation . 14
Figure 2 – Illustrative example of EES system charging-discharging cycle . 16
Figure 3 – Illustrative example of EES system power capability chart . 17
Figure 4 – Illustrative example of EES system response performances . 30
Figure 5 – EES system architecture with one POC type . 33
Figure 6 – EES system architecture with two POC types . 34
Figure 7 – Illustrative example of EES system available energies relation . 38
Table 1 – Illustrative example of EES system efficiency chart . 27
IEC 62933-1:2024 © IEC 2024 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL ENERGY STORAGE (EES) SYSTEMS –
Part 1: Vocabulary
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 62933-1 has been prepared by IEC technical committee 120: Electrical Energy Storage
(EES) systems. It is an International Standard.
This second edition cancels and replaces the first edition published in 2018. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition (with revision) of the entries developed during the edition 1 stability period and,
therefore, included only in other IEC 62933 parts;
b) addition of the entries developed during the edition 1 stability period and published in this
document for the first time;
c) complete revision of the entries already present in edition 1.
– 4 – IEC 62933-1:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
120/358/FDIS 120/367/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62933 series, published under the general title Electrical energy
storage (EES) systems, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.
IEC 62933-1:2024 © IEC 2024 – 5 –
INTRODUCTION
The purpose of this terminology document is to provide terms and definitions for all the
publications under the responsibility of TC 120, that standardize electrical energy storage
systems (EES systems) including unit parameters, test methods, planning, installation,
operation, safety and environmental issues. An EES system includes any type of grid-connected
energy storages which can both store electrical energy and provide electrical energy (from
electricity to electricity).
All TC 120 normative documents are subject to revision; this part of IEC 62933 will be revised
together with other TC 120 publications in order to avoid mismatches.
From the technical point of view, an EES system can be a complex multi-stage system with
several possible energy conversions. Each stage is made by well standardized components
(e.g. transformers, power conversion systems) or innovative components (e.g. new types of
batteries). Several IEC product standards give definitions necessary for the understanding of
certain terms used for these components. The International Electrotechnical Vocabulary (IEV,
http://www.electropedia.org), the IEC Glossary (http://std.iec.ch/glossary) and the ISO Online
Browsing Platform (OBP, http://www.iso.org/obp) allow online access to this information. This
document completes the need for precise terminology by giving definitions necessary at the
system level.
Without a strong standardization of EES system terminology, focal terms can have a different
meaning in EES systems related to different storage technologies. This aspect is critical also
from the market point of view. It impacts economics and this can become a barrier for tender
processes. The correct comparison among different options is fundamental, therefore basic
terms and definitions impact economic decisions.
Terms and definitions have been harmonized with the IEV, the OBP, the IEC Glossary and
relevant IEC documents as far as possible. Definitions not included in this terminology
document can be found elsewhere in other IEC documents.
The use of abbreviated terms has been optimized: on the one hand to avoid tedious repetition
and on the other hand to avoid confusion. A minimum set of abbreviated terms was identified
and used in the definitions, the other terms are written out in full spelling when needed. The
widely accepted abbreviated terms are:
EESS – EES system – Electrical energy storage system
EES – Electrical energy storage
POC – Point of connection
In order to facilitate document usage, Clause A.1 offers a term index and Clause A.2 offers an
abbreviated term index.
– 6 – IEC 62933-1:2024 © IEC 2024
ELECTRICAL ENERGY STORAGE (EES) SYSTEMS –
Part 1: Vocabulary
1 Scope
This part of IEC 62933 defines terms applicable to electrical energy storage (EES) systems
including terms necessary for the definition of unit parameters, test methods, planning,
installation, operation, environmental and safety issues.
This terminology document is applicable to grid-connected systems able to extract electrical
energy from an electric power system, store energy internally, and provide electrical energy to
an electric power system. The step for charging and discharging an EES system can comprise
an energy conversion.
2 Normative references
There are no normative references in this document.
3 Terms and definitions for EES systems classification
3.1 Fundamental concepts for EES systems classification
3.1.1
electrical energy storage
EES
electrical installation (IEV 826-10-01) able to absorb electrical energy, to store energy for a
certain duration and to provide electrical energy
EXAMPLE An installation that absorbs electrical energy to produce hydrogen by electrolysis, stores the hydrogen,
and uses that gas to produce electrical energy is an electrical energy storage.
Note 1 to entry: The term "electrical energy storage" can also be used to indicate the activity that an installation,
described in the definition, carries out when performing its functions.
Note 2 to entry: The term "electrical energy storage" is generally not used to designate a grid-connected installation,
for which electrical energy storage system (3.1.2) is the appropriate term.
Note 3 to entry: Energy conversion processes can be included during energy absorption, storage or release.
[SOURCE: IEC 60050-631:2023, 631-01-01, modified – minor editorial modifications in the
definition and in the note 2.]
3.1.2
electrical energy storage system
EES system
EESS
grid-connected installation (IEV 826-10-01) with defined electrical boundaries, comprising at
least one electrical energy storage (3.1.1), which extracts electrical energy from an electric
power system (IEV 601-01-01), stores this energy internally in some manner and provides
electrical energy to an electric power system (IEV 601-01-01), including grid-connection works
and which can include civil engineering works, energy conversion equipment and related
ancillary equipment
Note 1 to entry: The EES system is controlled and coordinated to provide services to the electric power system
(IEV 601-01-01) operators or to the electric power system users.
IEC 62933-1:2024 © IEC 2024 – 7 –
Note 2 to entry: In some cases, an EES system can require an additional non-electrical energy source during its
discharge, providing more energy to the electric power system than the energy it stored. A compressed air energy
storage (CAES) is a typical example where additional thermal energy is required.
[SOURCE: IEC 60050-631:2023, 631-01-02, modified – minor editorial modifications in the
definition and in the note 2.]
3.1.3
utility grid
part of an electric power network (IEV 601-01-02) that is operated by a system operator (IEV
617-02-09) within a defined area of responsibility
Note 1 to entry: A utility grid is normally used for electricity transfer from or to grid users or other grids. The grid
users can be electricity producers or consumers. The area of responsibility is fixed by relevant legislation or
regulation.
[SOURCE: IEC 60050-631:2023, 631-01-04 modified – system operator concept is added in the
definition and minor editorial modifications in the note 1.]
3.1.4
grid-connected, adj
connected to an electric power system (IEV 601-01-01)
3.1.5
islanded grid
electric island
part of an electric power system (IEV 601-01-01) that is electrically disconnected from the
remainder of the interconnected electric power system but remains energized from the local
electric power sources
[SOURCE: IEC 60050-692:2017, 692-02-11, modified – the term “islanded grid” has been
added and notes have been deleted.]
3.1.6
load profile
line graph illustrating the variation in loads over a specific time
3.1.7
allowed charging time
time period when an EES system is allowed to charge the accumulation subsystem in the peak
shaving application
3.1.8
allowed discharging time
time period when an EES system is allowed to discharge the accumulation subsystem in the
peak shaving application
3.2 EES systems classification
3.2.1
battery energy storage system
BESS
electrical energy storage system where the accumulation subsystem is a battery storage
subsystem (5.2.4)
EXAMPLE Flow battery energy system (IEC 62932-1:2019, 2.17), lithium ion battery (IEV 482-05-07) energy
storage system and lead acid battery energy storage system are different types of battery energy storage systems.
[SOURCE: IEC 60050-631:2023, 631-01-03, modified – battery storage subsystem concept
inserted in the definition, notes deleted and the example added.]
– 8 – IEC 62933-1:2024 © IEC 2024
3.2.2
capacitor energy storage system
CESS
electrical energy storage system with the accumulation subsystem based on capacitors
(IEV 151-13-28)
Note 1 to entry: Usually, capacitor energy storage systems are based on supercapacitors (IEV 114-03-03).
3.2.3
flywheel energy storage system
FESS
electrical energy storage system with the accumulation subsystem based on flywheels
Note 1 to entry: A flywheel is a mechanical device where rotational kinetic energy is stored.
3.2.4
low voltage EESS
EES system designed to be connected to a low voltage (IEV 601-01-26) primary POC
3.2.5
medium voltage EESS
EES system designed to be connected to a medium voltage (IEV 601-01-28) primary POC
3.2.6
high voltage EESS
EES system designed to be connected to a high voltage (IEV 601-01-27) primary POC
3.2.7
residential EESS
EES system designed for residential customer (IEV 617-02-05), excluding professional users
Note 1 to entry: A residential EES system is normally compliant with the applicable standards for residential devices
(e.g. electromagnetic compatibility).
Note 2 to entry: Professional users include commercial or industrial customers.
3.2.8
commercial EESS
EES system designed for professional users
Note 1 to entry: A commercial and industrial EES system is normally compliant with the applicable standards for
commercial or industrial devices (e.g. electromagnetic compatibility).
Note 2 to entry: Professional users include commercial or industrial customers.
3.2.9
utility EESS
EES system which is integrated into the utility grid and serving solely to ensure safe and reliable
operation of the electric power network (IEV 601-01-02)
[SOURCE: IEC 60050-631:2023, 631-01-05, modified – definition is reworded for better clarity.]
3.2.10
self-contained EES system
EES system whose components have been matched and partially or totally assembled at the
factory, that are shipped in one or more containers, and that are ready to be installed in the
field
Note 1 to entry: For a definition of container, refer to IEC TS 62686-1:2020, 3.1.2.
IEC 62933-1:2024 © IEC 2024 – 9 –
3.2.11
stationary EES system
EES system that, once installed and placed into service, is not intended to be moved from one
place to another
[SOURCE: IEC 60601-1:2005 and IEC 60601-1:2005/AMD1:2, 3.118, modified – definition has
been particularized for the EES system and the note to entry has been deleted.]
3.2.12
movable EES system
EES system mounted on a vehicle capable of being moved on a railway or road, to be connected
to primary POC at sites where temporary basis connection is planned
Note 1 to entry: The portable (IEV 151-16-47) concept cannot be applied to a grid connection installation like the
EES system, therefore a movable EES system cannot include such situation.
[SOURCE: IEC 60050-811:2017, 811-36-05, modified – definition has been particularized for
the EES system and the note to entry has been added.]
3.2.13
hybrid EES system
EES system with an accumulation subsystem composed of different storage technologies
EXAMPLE Hybrid EESS that incorporates batteries (IEV 482-01-04) and supercapacitors (IEV 114-03-03).
3.3 EES systems long-duration application
3.3.1
long-duration application
energy-intensive application
EES system application with long charge and discharge phases at variable powers
Note 1 to entry: Reactive power exchange with the electric power system (IEV 601-01-01) can be present along
with the active power (IEV 131-11-42) exchange.
Note 2 to entry: Long-duration application are generally not very demanding in terms of step response performances
but there are cases where high step response performances are required.
[SOURCE: IEC 60050-631:2023, 631-01-06 modified – alternate term deleted and part of the
definition moved in the note 2.]
3.3.2
active power flow control
long-duration application of an EES system used to compensate partially
or totally the active power (IEV 131-11-42) flow in a determined subsection of an electric power
system (IEV 601-01-01)
EXAMPLE Load shaving or levelling or shifting are active power flow controls.
Note 1 to entry: Active power flow control can require hours of continuous EES system charge or discharge.
3.3.3
feeder current control
long-duration application of an EES system used to maintain the current
in a certain grid branch within defined limits through active power (IEV 131-11-42) exchange
with the electric power network (IEV 601-01-02)
EXAMPLE Congestion relief is a feeder current control.
Note 1 to entry: Theoretically, feeder current control can also be realised by reactive power (IEV 131-11-44)
exchange. Because of typical distribution feeder characteristics such as the resistance-to-reactance ratio (R/X), the
active power (IEV 131-11-42) exchange is practically more effective in most cases.
– 10 – IEC 62933-1:2024 © IEC 2024
3.3.4
renewable energy resources generation firming
long duration application of an EES system used to decouple non-dispatchable renewable
energy source generation and electricity consumption for a specific time by absorbing energy
in periods with a surplus of energy generation and by provision of energy in periods with a
surplus of electricity consumption
3.3.5
peak shaving
limitation of the power consumption from the power grid to a maximum value by providing the
power exceeding the maximum value from other active power sources
3.3.6
fluctuation reduction of consumption
reduction of power oscillation of power consumption at the grid connection point by absorbing
the active power of the grid by EES systems at low power demand phases and by feeding in
additional active power by EES systems at high power demand phases
3.4 EES systems short-duration application
3.4.1
short-duration application
power intensive application
EES system application demanding in terms of step response performances and with frequent
charge and discharge phase transitions or with reactive power (IEV 131-11-44) exchange with
the electric power system (IEV 601-01-01)
[SOURCE: IEC 60050-631:2023, 631-01-07, modified – alternate term deleted and minor
editorial modifications in the definition.]
3.4.2
grid frequency control
power frequency control
frequency regulation
short-duration application of an EES system used for the stabilization of the electric power
system (IEV 601-01-01) frequency through active power (IEV 131-11-42) exchange
Note 1 to entry: The balancing of temporal variations of grid frequency occurs typically over time periods of the
order of seconds to minutes.
3.4.3
nodal voltage control
voltage support
short-duration application of an EES system used for the stabilization of the voltage at the
primary POC or neighbouring nodes through active or reactive power exchange
Note 1 to entry: Reactive power (IEV 131-11-44) is generally used in HV and MV grids, and active power
(IEV 131-11-42) in LV grids, depending on the resistance-to-reactance (R/X) ratio of the relevant lines.
3.4.4
power quality event mitigation
short-duration application of an EES system used to mitigate conducted disturbances in electric
power systems (IEV 601-01-01) such as short-duration supply interruptions, voltage dips,
voltage swells, voltage and currents harmonics, transient overvoltages, rapid voltage changes,
through active or reactive power exchange with the electric power network (IEV 601-01-02)
Note 1 to entry: The mitigation of power quality (IEV 617-01-05) events, except supply interruptions and harmonics,
occurs typically over time periods of the order of milliseconds to seconds. Power quality events are described in
IEC TS 62749.
Note 2 to entry: In power quality event mitigation, active and reactive power exchange can be intended also in
relation to harmonics and interharmonics.
IEC 62933-1:2024 © IEC 2024 – 11 –
Note 3 to entry: Theoretically a supply interruption can have a long duration, but practically most of the supply
interruptions have a duration ≤ 1 min. The mitigation of events with duration > 1 min is defined as outage mitigation.
3.4.5
reactive power flow control
short-duration application of an EES system used to compensate partially or totally the reactive
power (IEV 131-11-44) flow in a determined subsection of an electric power system (IEV 601-
01-01)
EXAMPLE Power factor adjustment of loads, normally obtained by capacitor banks, is a reactive power flow control.
3.4.6
fast frequency response
fast frequency control
short-duration application of an EES system used to contain the frequency change of the
electric power system (IEV 601-01-01) during sudden failures and reduce the amplitude of the
transient frequency difference, through the capability to actively support grid frequency by
discharging or charging very fast (e.g. within 100 ms)
3.4.7
fluctuation reduction
power smoothing
short-duration application of an EES system used to reduce power oscillation fluctuation of
power generation units (especially renewable energy sources) with regard to their points of
connection (4.1.3) absorbing active power at times of high generation output and by feeding in
additional active power at times of low generation output
3.4.8
power oscillation damping
POD
short-duration application of an EES system used to restrain power oscillations in one or more
connected AC electric power networks (IEV 601-01-02) by active or reactive power flow control
Note 1 to entry: Low frequency power oscillation range is typically from 0,1 Hz to 2 Hz.
3.4.9
primary frequency control
primary frequency regulation
short-duration application of an EES system used to stabilize the electric power system
(IEV 601-01-01) frequency on a steady state value through the capability to respond to a
measured frequency deviation
Note 1 to entry: Primary frequency control is a proportional control (also known as droop control) which is usually
activated by an autonomous primary control system with a dead time of less than a few seconds from the measured
frequency deviation and fully activated according a given ramp rate.
3.4.10
secondary frequency control
secondary frequency regulation
short-duration application of an EES system used to restore system frequency to the nominal
system frequency usually following a primary frequency regulation
Note 1 to entry: Generally, the secondary frequency control is manually or automatically activated between 30 s up
to 15 min from the primary frequency regulation completion.
3.4.11
voltage sag mitigation
voltage dip mitigation
short-duration application of an EES system used to compensate the voltage drop during a
specified time and for a predefined maximum power, when a voltage sag occurred at the primary
POC
– 12 – IEC 62933-1:2024 © IEC 2024
Note 1 to entry: The power quality events are described in IEC TS 62749. Voltage dip and voltage sag are frequently
used as synonyms.
3.5 EES systems hybrid and emergency application
3.5.1
hybrid application
EES system application demanding in terms of step response performances but with frequent
and long discharge phases at variable discharge power
Note 1 to entry: Emergency use cases, for example with uninterruptible power supplies, are included in this
application class.
[SOURCE: IEC 60050-631:2023, 631-01-08, modified – in the term "and emergency" has been
removed", "generally" has been removed from the definition, and the note 1 has been added.]
3.5.2
outage mitigation
back-up power
hybrid application of an EES system used to provide electrical energy during a specified time
and for a pre-defined maximum power, during which the main electrical energy supply is not
available at the primary POC
Note 1 to entry: In theory a supply interruption can have a long duration; in practice the majority of them have a
duration ≤ 1 min. The mitigation of events with a duration ≤ 1 min is defined as power quality (IEV 617-01-05) event
mitigation. Power quality events are described in IEC TS 62749.
3.5.3
back-up power supply
provision of power to all internal loads connected to user side equipment during a specified time
period without relying on an external power source in the event of electrical grid outage
3.5.4
black start capability
capability of the EES system to start the electric power system (IEV 601-01-01) only with
internal energy resources
3.5.5
emergency load
set of devices and equipment that should be operated during an electrical grid outage
3.5.6
emergency support
provision of power to emergency loads within a specified time and duration without relying on
an external power source in the event of electrical grid outage
4 Terms and definitions for EES systems specification
4.1 Fundamental concepts for EES systems specification
4.1.1
continuous operating conditions, pl
operating conditions within which the EES system is designed to operate within specified
performance limits
Note 1 to entry: The continuous operating conditions are usually defined at least as follows, but other conditions
can depend on the technology:
a. the voltage and frequency at POCs are within the continuous operating ranges;
b. the EES system is fully available;
c. the EES system is within the reference environmental conditions.
IEC 62933-1:2024 © IEC 2024 – 13 –
[SOURCE: IEC 60050-631:2023, 631-02-03, modified – in the note, the text has been slightly
changed for better clarity.]
4.1.2
reference environmental conditions
range of physical conditions under which the EES system is designed to operate continuously
EXAMPLE Ambient temperature range, pressure range, radiation range, humidity range and chemical spray are
some typical examples.
[SOURCE: IEC 60050-631:2023, 631-02-10, modified – in the definition, "range of" has been
added and the examples have been moved to a note to entry.]
4.1.3
point of connection
POC
reference point on the electric power system (IEV 601-01-01) where an EES system is
connected
Note 1 to entry: An EES system can have several POCs, classified as primary POC or auxiliary POC. In the absence
of an auxiliary POC, the primary POC can be named simply as POC. From an auxiliary POC it is not possible to
charge or discharge electrical energy, but a primary POC can be used to feed the auxiliary subsystem and the control
subsystem.
[SOURCE: IEC 60050-631:2023, 631-02-04, modified – in the definition "at which" has been
replace with "where" and the figures have been deleted.]
4.1.4
connection terminal
component of an EES system used for the connection to a POC
Note 1 to entry: An EES system can have several connection terminals arranged in two different classes: primary
connection terminals and auxiliary connection terminals. In the absence of an auxiliary POC, the primary connection
terminal can be referred to simply as connection terminal.
4.1.5
communication interface
interface (IEV 351-42-25) which provides input signals to the EES system and receives from it
output signals for control or measurement purposes, or which enables digital communication
with other systems or devices
Note 1 to entry: The communication interface is usually designed to a specific standard (e.g. IEC 62680 series or
others) and used for transmitting control and measurement data at the physical layer.
4.1.6
EES system full
condition of an EES system where the accumulation subsystem cannot charge additional energy
4.1.7
EES system empty
condition of an EES system where the accumulation subsystem cannot discharge additional
energy
4.1.8
energy storage capacity
E
C
difference in energy content of the EESS accumulation subsystem in given operating conditions
between EES system full (4.1.6) and EES system empty (4.1.7)
Note 1 to entry: Joule (J) is the coherent SI unit, other units can be chosen for convenience as well (kWh, MWh).
– 14 – IEC 62933-1:2024 © IEC 2024
Note 2 to entry: The term "energy storage capacity" is not to be mixed up with the term "capacity" (IEV 482-03-14),
used for cells or batteries, which represents electric charge (IEV 113-02-10), usually expressed in coulombs (C) or
amperes-hours (Ah).
Note 3 to entry: The only EESS's subsystem where significant energy is stored is the accumulation subsystem.
Other equipment of an EES system which stores negligible amounts of energy (e.g. filter capacitors, current
smoothing coils) or energy not usable at the primary POC (e.g. emergency power units in the auxiliary supply system)
is not considered in the energy storage capacity. The energy storage capacity is only linked to accumulation
subsystem, therefore, it is also weakly dependent to the input or output power values at the primary POC.
Note 4 to entry: In Figure 1, the relation for the main energy storage capacities is reported, where effective energy
storage capacity higher than input energy storage capacity is an illustrative hypothesis.
Key
█ Losses during charge
█ Losses during discharge
█ Not accessible energy storage capacity
█ Irreversible or reversible degradation
█ Output energy storage capacity
See also Figure 7.
Figure 1 – Illustrative example of EES system energy storage capacities relation
4.1.9
effective energy storage capacity
energy storage capacity potentially modified over time as the EES system characteristics
degrade
Note 1 to entry: Typically, the energy storage capacity varies along the EES system service life: energy storage
capacity at the beginning of service life (E ) and energy storage capacity at the end of service life (E ) are
C,BOL C,EOL
typical cases. Some degradation factors (like ageing) are irreversible and they imply a reduction of the energy storage
capacity, other factors are reversible (like temporary faults) and they make an energy storage capacity restoration
during the service life possible.
Note 2 to entry: For a BESS, effective energy storage capacity is typically the sum of the nameplate energy content
of all the batteries (IEV 482-01-04).
4.1.10
accessible energy storage capacity
usable energy storage capacity
part of the effective energy storage capacity that the EES system user has the permission to
have access to at a certain condition
IEC 62933-1:2024 © IEC 2024 – 15 –
Note 1 to entry: The accessible energy storage capacity is based on the decisions of the EES system manufacturer,
owner or operator.
4.1.11
energy stored on investment
ESOI
amount of energy that can be stored by an EES system during its service life, divided by the
amount of energy required to build, deinstall and recycle that EES system
Note 1 to entry: The ESOI quantifies the energetic benefit of an EES system.
4.1.12
nominal value
value of a quantity used to design
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...