HD 60364-5-551:2010

SLOVENSKI STANDARD
01-maj-2010
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Low-voltage electrical installations -- Part 5-55: Selection and erection of electrical
equipment - Other equipment -- Clause 551: Low-voltage generating sets
Errichten von Niederspannungsanlagen -- Teil 5-55: Auswahl und Errichtung elektrischer
Betriebsmittel - Andere Betriebsmittel - Abschnitt 551:
Niederspannungsstromerzeugungseinrichtungen
Installations électriques à basse tension -- Partie 5-55: Choix et mise en oeuvre des
matériels électriques - Autres matériels -- Article 551: Groupes générateurs à basse
tension
Ta slovenski standard je istoveten z: HD 60364-5-551:2010
ICS:
29.160.40 (OHNWULþQLDJUHJDWL Generating sets
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

HARMONIZATION DOCUMENT
HD 60364-5-551
DOCUMENT D'HARMONISATION
February 2010
HARMONISIERUNGSDOKUMENT
ICS 91.140 Supersedes HD 384.5.551 S1:1997

English version
Low-voltage electrical installations -
Part 5-55: Selection and erection of electrical equipment -
Other equipment -
Clause 551: Low-voltage generating sets
(IEC 60364-5-55:2001/A2:2008 (CLAUSE 551))

Installations électriques à basse Errichten von Niederspannungsanlagen -
tension - Teil 5-55: Auswahl und Errichtung elektrischer
Partie 5-55: Choix et mise en oeuvre Betriebsmittel -
des matériels électriques - Andere Betriebsmittel -
Autres matériels - Abschnitt 551:
Article 551: Groupes générateurs à Niederspannungsstromerzeugungseinrichtungen
basse tension (IEC 60364-5-55:2001/A2:2008 (CLAUSE 551))
(CEI 60364-5-55:2001/A2:2008
(CLAUSE 551))
This Harmonization Document was approved by CENELEC on 2009-10-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for implementation of this
Harmonization Document at national level.

Up-to-date lists and bibliographical references concerning such national implementations may be obtained on
application to the Central Secretariat or to any CENELEC member.

This Harmonization Document exists in three official versions (English, French, German).

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, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: Avenue Marnix 17, B - 1000 Brussels

© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. HD 60364-5-551:2010 E

Foreword
The text of the International Standard IEC 60364-5-55:2001/A2:2008, Clause 551, prepared by
IEC TC 64, Electrical installations and protection against electric shock, was submitted to the CENELEC
Unique Acceptance Procedure and was approved by CENELEC as HD 60364-5-551 on 2009-10-01.
This document supersedes HD 384.5.551 S1:1997.
In this standard, the common modifications to the International Standard are indicated by a vertical line in
the left margin of the text.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the HD has to be implemented

at national level by publication of a harmonized

national standard or by endorsement
(dop) 2010-10-01
– latest date by which the national standards conflicting

with the HD have to be withdrawn
(dow) 2012-10-01
For this Harmonization Document the informative Annex A of IEC 60364-5-55:2001/A2:2008 shall be
disregarded and has been replaced by the normative Annex ZA, Special national conditions.
Annexes ZA and ZB have been added by CENELEC.
__________
– 3 – HD 60364-5-551:2010
551 Low-voltage generating sets
551.1 Scope
This clause provides requirements for the selection and erection of low-voltage and extra-low voltage
generating sets intended to supply, either continuously or occasionally, all or part of the installation.
Requirements are also included for installations with the following supply arrangements:
– supply to an installation which is not connected to a system for distribution of electricity to the public;
– supply to an installation as an alternative to a system for distribution of electricity to the public;
– supply to an installation in parallel with a system for distribution of electricity to the public supply;
– appropriate combinations of the above.
This part does not apply to self-contained items of extra-low voltage electrical equipment which
incorporate both the source of energy and the energy-using load and for which a specific product
standard exists that includes the requirements for electrical safety.
NOTE Requirements of the electricity distributor should be ascertained before a generating set is installed in an installation that is
connected to a system for distribution of electricity to the public.
551.1.1  Generating sets with the following power sources are considered:
– combustion engines;
– turbines;
– electric motors;
– photovoltaic cells (HD 60364-7-712 also applies);
– electrochemical accumulators;
– other suitable sources.
551.1.2  Generating sets with the following electrical characteristics are considered:
– mains-excited and separately excited synchronous generators;
– mains-excited and self-excited asynchronous generators;
– mains-commutated and self-commutated static converters with or without by-pass facilities;
– generating sets with other suitable electrical characteristics.
551.1.3 The use of generating sets for the following purposes is considered:
– supply to permanent installations;
– supply to temporary installations;
– supply to mobile equipment which is not connected to a permanent installation;
– supply to mobile units (HD 60364-7-717 also applies).
551.2  General requirements
551.2.1 The means of excitation and commutation shall be appropriate for the intended use of the
generating set and the safety and proper functioning of other sources of supply shall not be impaired by
the generating set.
NOTE See 551.7 for particular requirements where the generating set may operate in parallel with a system for the distribution of
electricity to the public.
551.2.2 The prospective short-circuit current and prospective earth fault current shall be assessed for
each source of supply or combination of sources which can operate independently of other sources or
combinations. The short-circuit breaking capacity of protective devices within the installation and, where
appropriate, connected to a system for distribution of electricity to the public, shall not be exceeded for
any of the intended methods of operation of the sources.
NOTE Attention should be given to the power factor specified for protective devices in the installation.
551.2.3 The capacity and operating characteristics of the generating set shall be such that danger or
damage to equipment does not arise after the connection or disconnection of any intended load as a
result of the deviation of the voltage or frequency from the intended operating range. Means shall be
provided to automatically disconnect such parts of the installation as may be necessary if the capacity of
the generating set is exceeded.
NOTE 1 Attention should be given to the size of individual loads as a proportion of the capacity of the generating set and to motor
starting currents.
NOTE 2 Attention should be given to the power factor specified for protective devices in the installation.
NOTE 3 The installation of a generating set within an existing building or installation may change the conditions of external
influence for the installation (see HD 60364-1), for example by the introduction of moving parts, parts at high temperature or by the
presence of inflammable fluids and noxious gases, etc.
551.2.4 Provision for isolation shall meet the requirements of Clause 537 for each source or
combination of sources of supply.
551.3  Protective measure: extra-low-voltage provided by SELV and PELV
551.3.1 Additional requirements for SELV and PELV where the installation is supplied from
more than one source
Where a SELV or PELV system may be supplied by more than one source, the requirements of 414.3 of
HD 60364-4-41 shall apply to each source. Where one or more of the sources is earthed, the
requirements for PELV systems in 414.4 of HD 60364-4-41 shall apply.
If one or more of the sources does not meet the requirements of 414.3, the system shall be treated as a
FELV system and the requirements of 411.7 of HD 60364-4-41 shall apply.
551.3.2 Additional requirements where it is necessary to maintain the supply to an extra-low
voltage system
Where it is necessary to maintain the supply to an extra-low voltage system following the loss of one or
more sources of supply, each source of supply or combination of sources of supply which can operate
independently of other sources or combinations shall be capable of supplying the intended load of the
extra-low voltage system. Provisions shall be made that the loss of low-voltage supply to an extra-low
voltage source does not lead to danger or damage to other extra-low voltage equipment.
1)
NOTE Such precautions can be necessary in supplies for safety services (see Part 56 of IEC 60364).
551.4  Fault protection (protection against indirect contact)
551.4.1 Fault protection shall be provided for the installation in respect of each source of supply or
combination of sources of supply that can operate independently of other sources or combinations of
sources.
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1)
HD 60364-5-56 under preparation.

– 5 – HD 60364-5-551:2010
The fault protective provisions shall be selected or precautions shall be taken to ensure that where fault
protective provisions are achieved in different ways within the same installation or part of an installation
according to the active sources of supply, no influence shall occur or conditions arise that could impair the
effectiveness of the fault protective provisions.
NOTE This might, for example, require the use of a transformer providing electrical separation between parts of the installation
using different system earthing.
551.4.2 The generating set shall be connected so that any provision within the installation for protection
by residual current devices in accordance with HD 60364-4-41 remains effective for every intended
combination of sources of supply.
NOTE Connection of live parts of the generator with earth can affect the protective measures.
551.4.3 Protection by automatic disconnection of supply
551.4.3.1  General
Where the protective measure automatic disconnection of supply is used for protection against electric
shock, the requirements of Clause 411 of HD 60364-4-41 apply, except as modified for the particular
cases given in 551.4.3.2 or 551.4.3.3.
551.4.3.2  Additional requirements for installations where the generating set provides a supply as
a switched alternative to the normal supply to the installation
Protection by automatic disconnection of supply shall not rely upon the connection to the earthed point of
the distribution system when the generator is operating as a switched alternative. A suitable means of
earthing shall be provided.
551.4.3.3  Additional requirements for installations incorporating static converters
551.4.3.3.1 Where fault protection for parts of the installation supplied by the static converter relies upon
the automatic closure of the by-pass switch and the operation of protective devices on the supply side of
the by-pass switch is not within the time required by Clause 411 of HD 60364-4-41, supplementary
equipotential bonding shall be provided between simultaneously accessible exposed-conductive-parts
and extraneous-conductive-parts on the load side of the static converter in accordance with 415.2 of
HD 60364-4-41.
The resistance of supplementary equipotential bonding conductors required between simultaneously
accessible conductive parts shall fulfill the following condition in case of a.c.:
50V
R ≤
I
a
where
I is the maximum earth fault current which can be supplied by the static converter alone for a period of
a
up to 5 s.
NOTE Where such equipment is intended to operate in parallel with a system for distribution of electricity to the public, the
requirements of 551.7 also apply.
551.4.3.3.2 Precautions shall be taken or equipment shall be selected so that the correct operation of
protective devices is not impaired by d.c. currents generated by a static converter or by the presence of
filters.
551.4.3.3.3 A means of isolation shall be installed on both sides of a static converter.
This requirement does not apply on the power source side of a static converter which is integrated in the
same enclosure as the power source.
551.5 Protection against overcurrent
551.5.1 Where overcurrent protection of the generating set is required, it shall be located as near as
practicable to the generator terminals.
NOTE The contribution to the prospective short-circuit current by a generating set can be time-dependent and can be much less
than the contribution made by a system where the source is a mv/lv transformer.
551.5.2 Where a generating set is intended to operate in parallel with another source of supply,
including a supply from a system for distribution of electricity to the public, or where two or more
generating sets may operate in paralle
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