SIST EN 50522:2011
(Main)Earthing of power installations exceeding 1 kV a.c.
Earthing of power installations exceeding 1 kV a.c.
This European Standard contains the requirements for the design and erection of earthing 111 systems of electrical installations, in systems with nominal voltage above 1 kV a.c., so as to 112 provide safety and proper functioning for the use intended.
Erdung von Starkstromanlagen mit Nennwechselspannungen über 1 kV
Diese Europäische Norm ist anwendbar zur Festlegung von Anforderungen für die Projektierung und Errichtung von Erdungsanlagen für Starkstromanlagen in Netzen mit Nennwechselspannungen über 1 kV und einer Nennfrequenz bis einschließlich 60 Hz, um damit eine sichere und störungsfreie Funktion im bestimmungsgemäßen Betrieb sicherzustellen. Im Sinne dieser Norm gilt als eine Starkstromanlage eine der folgenden: a) Schalt- und Umspannanlagen, einschließlich Schaltanlagen zur Speisung von Bahnanlagen; b) elektrische Anlagen auf Masten oder in Türmen, Schaltgeräte und/oder Transformatoren außerhalb abgeschlossener elektrischer Betriebsstätten; c) eine (oder mehrere) Stromerzeugungsanlage(n) an einem räumlich begrenzten Ort; die Anlage enthält Generatoren und Transformatoren mit zugehörigen Schaltgeräten und elektrischen Hilfseinrichtungen. Verbindungen zwischen Stromerzeugungsanlagen an unterschiedlichen Orten sind ausgeschlossen; d) das elektrische Netz einer Fabrik, Industrieanlage oder anderer industrieller, landwirtschaftlicher, gewerblicher oder öffentlicher Räumlichkeiten. In Starkstromanlagen können unter anderem folgende Betriebsmittel vorkommen: - Drehende elektrische Maschinen; - Schaltgeräte; - Transformatoren und Reaktoren; - Stromrichter; - Kabel; - Verdrahtungen; - Batterien; - Kondensatoren; - Erdungsanlagen; - Gebäude und Umzäunungen, die zu einer abgeschlossenen elektrischen Betriebsstätte gehören; - zugehörige Schutz-, Steuerungs- und Hilfssysteme; - große Luftdrosselspulen. ANMERKUNG Grundsätzlich haben Festlegungen von Betriebsmittelnormen Vorrang vor dieser Norm. Diese Europäische Norm gilt nicht für die Projektierung und Errichtung von Erdungsanlagen für eine der folgenden: - Freileitungen und Kabeln zwischen getrennten Anlagen; - elektrische Bahnen; - Bergwerksausrüstungen und -anlagen; - Leuchtröhrenanlagen; - Anlagen auf Schiffen und off-shore-Plattformen; - elektrostatischen Einrichtungen (z.B. Elektrofilter, Pulverbeschichtungsanlagen); - Prüffeldern; - medizinischen Einrichtungen, zum Beispiel medizinischen Röntgeneinrichtungen. Diese Europäische Norm gilt nicht für die Anforderungen zur Durchführung von Arbeiten unter Spannung an elektrischen Anlagen.
Prises de terre des installations électriques en courant alternatif de puissance supérieure à 1 kV
Ozemljitev elektroenergetskih postrojev, ki presegajo 1 kV izmenične napetosti
Ta evropski standard vsebuje zahteve za načrtovanje in postavitev ozemljitve električnih inštalacij sistemov 111 v sisteme z nazivno napetostjo nad 1 kV izmeničnega toka, tako da 112 zagotavljajo varnost in primerno delovanje za predvideno uporabo.
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 50522:2011
01-januar-2011
1DGRPHãþD
SIST HD 637 S1:1999
2]HPOMLWYHPRþQRVWQLKLQãWDODFLMNLSUHVHJDMRN9L]PHQLþQHQDSHWRVWL
Earthing of power installations exceeding 1 kV a.c.
Erdung von Starkstromanlagen mit Nennwechselspannungen über 1 kV
Prises de terre des installations électriques en courant alternatif de puissance supérieure
à 1 kV
Ta slovenski standard je istoveten z: EN 50522:2010
ICS:
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
SIST EN 50522:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 50522:2011
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SIST EN 50522:2011
EUROPEAN STANDARD
EN 50522
NORME EUROPÉENNE
November 2010
EUROPÄISCHE NORM
ICS 29.120.50 Supersedes HD 637 S1:1999 (partially)
English version
Earthing of power installations exceeding 1 kV a.c.
Prises de terre des installations Erdung von Starkstromanlagen mit
électriques en courant alternatif de Nennwechselspannungen über 1 kV
puissance supérieure à 1 kV
This European Standard was approved by CENELEC on 2010-11-01. 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 Central Secretariat 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 Central Secretariat 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, 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
Management Centre: 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. EN 50522:2010 E
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SIST EN 50522:2011
EN 50522:2010 – 2 –
Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 99X, Power
installations exceeding 1 kV a.c. (1,5 kV d.c.). It was submitted to formal vote and was accepted by
CENELEC as EN 50522 on 2010-11-01.
Together with EN 61936-1:2010 this document supersedes HD 637 S1:1999.
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 EN has to be implemented
at national level by publication of an identical
(dop) 2011-11-01
national standard or by endorsement
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2013-11-01
NOTE The text identical with IEC 61936-1 is written in italics.
__________
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SIST EN 50522:2011
– 3 – EN 50522:2010
Contents
1 Scope .6
2 Normative references .7
3 Terms and definitions .8
3.1 General definitions .8
3.2 Definitions concerning installations .8
3.3 Definitions concerning safety measures against electric shock .9
3.4 Definitions concerning earthing .9
4 Fundamental requirements .18
4.1 General requirements .18
4.2 Electrical requirements .18
4.3 Safety criteria .19
4.4 Functional requirements .20
5 Design of earthing systems .20
5.1 General .20
5.2 Dimensioning with respect to corrosion and mechanical strength .20
5.3 Dimensioning with respect to thermal strength .21
5.4 Dimensioning with regard to touch voltages .23
6 Measures to avoid transferred potential .27
6.1 Transferred potential from High voltage systems to Low voltage systems .27
6.2 Transferred potentials to telecommunication and other systems .28
7 Construction of earthing systems .29
7.1 Installation of earth electrodes and earthing conductors .29
7.2 Lightning and transients .29
7.3 Measures for earthing on equipment and installations .30
8 Measurements .30
9 Maintainability .30
9.1 Inspections .30
9.2 Measurements .30
Annex A (normative) Method of calculating permissible touch voltages .31
Annex B (normative) Touch voltage and body current .32
B.1 Calculation of permissible touch voltage .32
B.2 Calculation of prospective permissible touch voltage .33
Annex C (normative) Type and minimum dimensions of earth electrode materials ensuring
mechanical strength and corrosion resistance .36
Annex D (normative) Current rating calculation of earthing conductors and earth electrodes .37
Annex E (normative) Description of the recognized specified measures M .41
Annex F (normative) Measures on earthing systems to reduce the effects of high frequency
interference .44
Annex G (normative) Detailed measures for earthing of equipment and installations .45
G.1 Fences around substation installations .45
G.2 Pipes .45
G.3 Traction rails .45
G.4 Pole mounted transforming and/or switching installations .45
G.5 Secondary circuits of instrument transformers .46
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SIST EN 50522:2011
EN 50522:2010 – 4 –
Annex H (normative) Measuring touch voltages .47
Annex I (informative) Reduction factors related to earth wires of overhead lines and metal
sheaths of underground cables .48
I.1 General .48
I.2 Typical values of reduction factors of overhead lines and cables (50 Hz) .48
Annex J (informative) Basis for the design of earthing systems .50
J.1 Soil resistivity .50
J.2 Resistance to earth .50
Annex K (informative) Installing the earth electrodes and earthing conductors .54
K.1 Installation of earth electrodes .54
K.2 Installation of earthing conductors .54
Annex L (informative) Measurements for and on earthing systems .56
L.1 Measurement of soil resistivities .56
L.2 Measurement of resistances to earth and impedances to earth .56
L.3 Determination of the earth potential rise .57
L.4 Elimination of interference and disturbance voltages for earthing measurements .58
Annex M (normative) Details on site inspection and documentation of earthing systems .61
Annex N (informative) The use of reinforcing bars in concrete for earthing purpose .62
Annex O (informative) Global Earthing System .63
Annex P (normative) Special national conditions .64
Annex Q (informative) A-deviations .65
Figure 1 - Example for the surface potential profile and for the voltages in case of current carrying
earth electrodes .14
Figure 2 - Example for currents, voltages and resistances for an earth fault in a transformer
substation with low impedance neutral earthing .15
Figure 3 - Essential components of earth fault currents in high voltage systems .17
Figure 4 - Permissible touch voltage .25
Figure 5 - Design of earthing systems, if not part of a global earthing system (C1 of 5.4.2 ), with
regard to permissible touch voltage U by checking the earth potential rise U or the touch voltage
Tp E
U .26
T
Figure B.1 - Scheme of the touching circuit .34
Figure B.2 - Examples for curves U = f (t ) for different additional resistances R = R + R .35
vTp f F F1 F2
Figure D.1 - Short circuit current density G for earthing conductors and earth electrodes relative to
the duration of the fault current t .38
F
Figure D.2 - Continuous current I for earthing conductors .40
D
Figure J.1 - Resistance to earth of horizontal earth electrodes (made from strip, round material or
stranded conductor) for straight or ring arrangement in homogeneous soil .51
Figure J.2 - Resistance to earth of earth rods, vertically buried in homogeneous soil .52
Figure J.3 - Typical values for the resistance to earth of a cable with earth electrode effect
depending on the length of the cable and the soil resistivity.53
Figure L.1 - Example for the determination of the impedance to earth by the heavy-current
injection method.60
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SIST EN 50522:2011
– 5 – EN 50522:2010
Table 1 - Relevant currents for the design of earthing systems .22
Table 2 - Minimum requirements for interconnection of low voltage and high voltage earthing
systems based on EPR limits .28
Table B.1 - Permissible body current I depending on the fault duration t .32
B f
Table B.2 - Total human body impedance Z related to the touch voltage U for a current path
B T
hand to hand .32
Table B.3 - Calculated values of the permissible touch voltage U as a function of the fault
Tp
duration t .33
f
Table B.4 - Assumption for calculations with additional resistances .33
Table D.1 - Material constants .37
Table D.2 - Factors for conversion of continuous current from 300 °C final temperature to another
final temperature .38
Table E.1 - Conditions for the use of recognized specified measures M to ensure permissible
touch voltages U (see Figure 4) .41
Tp
Table J.1 - Soil resistivities for frequencies of alternating currents (Range of values, which were
frequently measured) .50
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SIST EN 50522:2011
EN 50522:2010 – 6 –
1 Scope
This European Standard is applicable to specify the requirements for the design and erection of earthing
systems of electrical installations, in systems with nominal voltage above 1 kV a.c. and nominal frequency
up to and including 60 Hz, so as to provide safety and proper functioning for the use intended.
For the purpose of interpreting this standard, an electrical power installation is considered to be one of the
following:
a) substation, including substation for railway power supply;
b) electrical installations on mast, pole and tower;
switchgear and/or transformers located outside a closed electrical operating area;
c) one (or more) power station(s) located on a single site;
the installation includes generators and transformers with all associated switchgear and all electrical
auxiliary systems. Connections between generating stations located on different sites are excluded;
d) the electrical system of a factory, industrial plant or other industrial, agricultural, commercial or public
premises.
The electrical power installation includes, among others, the following equipment:
– rotating electrical machines;
– switchgear;
– transformers and reactors;
– converters;
– cables;
– wiring systems;
– batteries;
– capacitors;
– earthing systems;
– buildings and fences which are part of a closed electrical operating area;
– associated protection, control and auxiliary systems;
– large air core reactor.
NOTE In general, a standard for an item of equipment takes precedence over this standard.
This European Standard does not apply to the design and erection of earthing systems of any of the
following:
– overhead and underground lines between separate installations;
– electric railways;
– mining equipment and installations;
– fluorescent lamp installations;
– installations on ships and off-shore installations;
– electrostatic equipment (e.g. electrostatic precipitators, spray-painting units);
– test sites;
– medical equipment, e.g. medical X-ray equipment.
This European Standard does not apply to the requirements for carrying out live working on electrical
installations.
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SIST EN 50522:2011
– 7 – EN 50522:2010
2 Normative references
The following referenced documents are indispensable for the application 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 60529, Degrees of protection provided by enclosures (IP Code) (IEC 60529)
EN 60909, Short-circuit currents in three-phase a.c. systems (IEC 60909)
HD 60364-1, Low-voltage electrical installations – Part 1: Fundamental principles, assessment of general
characteristics, definitions (IEC 60364-1, modified)
HD 60364-4-41, Low-voltage electrical installations – Part 4-41: Protection for safety – Protection against
electric shock (IEC 60364-4-41, modified)
IEC 60050(151):2001, International Electrotechnical Vocabulary (IEV) – Part 151: Electrical and magnetic
devices
IEC 60050(195):1998, International Electrotechnical Vocabulary (IEV) – Part 195: Earthing and protection
against electric shock
IEC 60050(601):1985, International Electrotechnical Vocabulary (IEV) – Part 601: Generation,
transmission and distribution of electricity – General
IEC 60050(602):1983, International Electrotechnical Vocabulary (IEV) – Part 602: Generation,
transmission and distribution of electricity – Generation
IEC 60050(604):1987, International Electrotechnical Vocabulary (IEV) – Part 604: Generation,
transmission and distribution of electricity – Operation
IEC 60050(605):1983, International Electrotechnical Vocabulary (IEV) – Part 605: Generation,
transmission and distribution of electricity – Substations
IEC 60050(826):2004, International Electrotechnical Vocabulary (IEV) – Part 826: Electrical installations
IEC 60287-3-1, Electric cables – Calculation of the current rating – Part 3-1: Sections on operating
conditions – Reference operating conditions and selection of cable type
IEC/TS 60479-1:2005, Effects of current on human beings and livestock – Part 1: General aspects
IEC 60949:1988, Calculation of thermally permissible short-circuit currents, taking into account non-
adiabatic heating effects
IEC/TS 61000-5-2, Electromagnetic compatibility (EMC) – Part 5: Installation and mitigation
guidelines – Section 2: Earthing and cabling
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SIST EN 50522:2011
EN 50522:2010 – 8 –
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General definitions
3.1.1
electrical equipment
item used for such purposes as generation, conversion, transmission, distribution or utilization of electric
energy, such as electric machines, transformers, switchgear and controlgear, measuring instruments,
protective devices, wiring systems, current-using equipment
[IEV 826-16-01]
3.1.2
rated value
value of a quantity used for specification purposes, established for a specified set of operating conditions
of a component, device, equipment, or system
[IEV 151-16-08]
3.1.3
high voltage
voltage exceeding 1 000 V a.c.
3.1.4
low voltage
voltage not exceeding 1 000 V a.c.
3.1.5
operation
all activities, including both electrical and non-electrical work activities, necessary to permit the power
installation to function
NOTE These activities include switching, controlling, monitoring and maintenance
3.2 Definitions concerning installations
3.2.1
closed electrical operating area
room or location for operation of electrical installations and equipment to which access is intended to be
restricted to skilled or instructed persons or to lay personnel under the supervision of skilled or instructed
persons, e.g. by opening of a door or removal of protective barrier only by the use of a key or tool, and
which is clearly marked by appropriate warning signs
3.2.2
substation
part of a power system, concentrated in a given place, including mainly the terminations of transmission or
distribution lines, switchgear and housing and which may also include transformers. It generally includes
facilities necessary for system security and control (e.g. the protective devices)
NOTE According to the nature of the system within which the substation is included, a prefix may qualify it.
EXAMPLES: transmission substation (of a transmission system), distribution substation, 400 kV substation, 20 kV substation.
[IEV 605-01-01]
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SIST EN 50522:2011
– 9 – EN 50522:2010
3.2.3
power station
installation whose purpose is to generate electricity and which includes civil engineering works, energy
conversion equipment and all the necessary ancillary equipment
[IEV 602-01-01]
3.2.4
installations of open design
installations where the equipment does not have protection against direct contact
3.2.5
installations of enclosed design
installations where the equipment has protection against direct contact
NOTE For degrees of enclosure protection see EN 60529.
3.3 Definitions concerning safety measures against electric shock
3.3.1
protection against direct contact
measures which prevent persons coming into hazardous proximity to live parts or those parts which could
carry a hazardous voltage, with parts of their bodies or objects (reaching the danger zone)
3.3.2
protection in case of indirect contact
protection of persons from hazards which could arise, in event of fault, from contact with exposed
conductive parts of electrical equipment or extraneous conductive parts
3.3.3
enclosure
part providing protection of equipment against certain external influences and, in any direction, protection
against direct contact
3.4 Definitions concerning earthing
3.4.1
(local) earth
part of the Earth which is in electric contact with an earth electrode and the electric potential of which is
not necessarily equal to zero
NOTE The conductive mass of the earth, whose electric potential at any point is conventionally taken as equal to zero.
[IEV 195-01-03, modified]
3.4.2
reference earth
(remote earth)
part of the Earth considered as conductive, the electric potential of which is conventionally taken as zero,
being outside the zone of influence of the relevant earthing arrangement
NOTE The concept “Earth” means the planet and all its physical matter.
[IEV 195-01-01, modified]
3.4.3
earth electrode
conductive part, which may be embedded in a specific conductive medium, e.g. in concrete or coke, in
electric contact with the Earth
[IEV 195-02-01]
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SIST EN 50522:2011
EN 50522:2010 – 10 –
3.4.4
earthing conductor
conductor which provides a conductive path, or part of the conductive path, between a given point in a
system or in an installation or in equipment and an earth electrode
[IEV 195-02-03]
NOTE Where the connection between part of the installation and the earth electrode is made via a disconnecting link,
disconnecting switch, surge arrester counter, surge arrester control gap etc., then only that part of the connection permanently
attached to the earth electrode is an earthing conductor.
3.4.5
protective bonding conductor
protective conductor for ensuring equipotential bonding
3.4.6
earthing system
arrangement of connections and devices necessary to earth equipment or a system separately or jointly
[IEV 604-04-02]
3.4.7
earth rod
earth electrode consisting of a metal rod driven into the ground
[IEV 604-04-09]
3.4.8
structural earth electrode
metal part, which is in conductive contact with the earth or with water directly or via concrete, whose
original purpose is not earthing, but which fulfils all requirements of an earth electrode without impairment
of the original purpose
NOTE Examples of structural earth electrodes are pipelines, sheet piling, concrete reinforcement bars in foundations and the
steel structure of buildings, etc.
3.4.9
electric resistivity of soil,
E
resistivity of a typical sample of soil
3.4.10
resistance to earth, R
E
real part of the impedance to earth
3.4.11
impedance to earth, Z
E
impedance at a given frequency between a specified point in a system or in an installation or in equipment
and reference earth
NOTE The impedance to earth is determined by the directly connected earth electrodes and also by connected overhead earth
wires and wires buried in earth of overhead lines, by connected cables with earth electrode effect and by other earthing systems
which are conductively connected to the relevant earthing system by conductive cable sheaths, shields, PEN conductors or in
another way.
3.4.12
earth potential rise (EPR), U
E
voltage between an earthing system and reference earth
3.4.13
potential
voltage between an observation point and reference earth
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SIST EN 50522:2011
– 11 – EN 50522:2010
3.4.14
(effective) touch voltage, U
T
voltage between conductive parts when touched simultaneously
NOTE The value of the effective touch voltage may be appreciably influenced by the impedance of the person in electric contact
with these conductive parts.
[IEV 195-05-11, modified]
3.4.15
prospective touch voltage, U
vT
voltage between simultaneously accessible conductive parts when those conductive parts are not being
touched
[IEV 195-05-09, modified]
3.4.16
step voltage, U
S
voltage between two points on the earth’s surface that are 1 m distant from each other, which is
considered to be the stride length of a person
[IEV 195-05-12]
3.4.17
transferred potential
potential rise of an earthing system caused by a current to earth transferred by means of a
connected conductor (for example a metallic cable sheath, PEN conductor, pipeline, rail) into areas
with low or no potential rise relative to reference earth resulting in a potential difference occurring
between the conductor and its surroundings (Figure 1).
NOTE The definition also applies where a conductor, which is connected to reference earth, leads into the area of the potential
rise.
3.4.18
stress voltage
voltage appearing during earth fault conditions between an earthed part or enclosure of equipment or
device and any other of its parts and which could affect its normal operation or safety
3.4.19
global earthing system
equivalent earthing system created by the interconnection of local earthing systems that ensures, by the
proximity of the earthing systems, that there are no dangerous touch voltages
NOTE 1 Such systems permit the division of the earth fault current in a way that results in a reduction of the earth potential rise at
the local earthing system. Such a system could be said to form a q
...
SLOVENSKI SIST EN 50522
STANDARD
januar 2011
Ozemljitev elektroenergetskih postrojev, ki presegajo 1 kV izmenične
napetosti
Earthing of power installations exceeding 1 kV a.c.
Prises de terre des installations électriques en courant alternatif de puissance
supérieureŕ 1 kV
Erdung von Starkstromanlagen mit Nennwechselspannungen über 1 kV
Referenčna oznaka
ICS 29.240.01 SIST EN 50522:2011 (sl)
Nadaljevanje na straneh II in III ter od 1 do 64
© 2015-04. Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 50522 : 2011
NACIONALNI UVOD
Standard SIST EN 50522 (sl), Ozemljitev elektroenergetskih postrojev, ki presegajo 1 kV izmenične
napetosti, 2011, ima status slovenskega standarda in je istoveten evropskemu standardu EN 50522
(en), Earthing of power installations exceeding 1 kV a.c., 2010.
NACIONALNI PREDGOVOR
Evropski standard EN 50522:2010 je pripravil tehnični odbor CLC/TC 99X Elektroenergetski postroji,
ki presegajo 1 kV a. c. (1,5 kV d.c.).
Slovenski standard SIST EN 50522:2011 je prevod evropskega standarda EN 50522:2010. V primeru
spora glede besedila slovenskega prevoda v tem standardu je odločilen izvirni evropski standard v
angleškem jeziku. Slovensko izdajo standarda je potrdil Strokovni svet za področja elektrotehnike,
informacijske tehnologije in telekomunikacij.
Odločitev za privzem tega standarda je v novembru 2010 sprejel Strokovni svet SIST za področja
elektrotehnike, informacijske tehnologije in telekomunikacij.
ZVEZA Z NACIONALNIMI STANDARDI
S privzemom tega evropskega standarda veljajo za omejeni namen referenčnih standardov vsi
standardi, navedeni v izvirniku, razen standarda, ki je že sprejet v nacionalno standardizacijo:
SIST EN 60529 Stopnja zaščite, ki jo zagotavlja ohišje (koda IP) (IEC 60529:1989)
SIST EN 60909 Kratkostični toki v trifaznih izmeničnih sistemih
SIST HD 60364-1 Nizkonapetostne električne inštalacije – 1. del: Temeljna načela,
ocena splošnih karakteristik, definicije (IEC 60364-1:2005,
spremenjen)
SIST HD 60364-4-41 Nizkonapetostne električne inštalacije – 4-41. del: Zaščitni ukrepi –
Zaščita pred električnim udarom (IEC 60364-4-41:2005, spremenjen)
SIST IEC 60050-151:2006 Mednarodni elektrotehniški slovar – Poglavje 151: Električne in magnetne
naprave
SIST IEC 60050-195:2001 Mednarodni elektrotehniški slovar – Poglavje 195: Ozemljitev in zaščita
pred električnim udarom (in pri njem)
SIST IEC 60050(602):1999 Mednarodni elektrotehniški slovar – Poglavje 602: Proizvodnja, prenos in
razdeljevanje električne energije – Proizvodnja
SIST IEC 60050-604:1997 Mednarodni elektrotehniški slovar – Poglavje 604: Proizvodnja, prenos in
razdeljevanje električne energije – Obratovanje
SIST IEC 60050(605):1999 Mednarodni elektrotehniški slovar – Poglavje 605: Proizvodnja, prenos in
razdeljevanje električne energije – Postaje
SIST IEC 60050-826:2006 Mednarodni elektrotehniški slovar – 826. del: Električne inštalacije
SIST-TS IEC/TS 60479-1:2006 Vplivi električnega toka na človeka in živali – 1. del: Splošno
SIST IEC/TR 61000-5-2:1998 Elektromagnetna združljivost (EMC) – 5. del: Smernice za namestitev in
ublažitev – 2. razdelek: Ozemljevanje in kabljenje
OSNOVA ZA IZDAJO STANDARDA
– privzem standarda EN 50522:2010
II
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SIST EN 50522 : 2011
PREDHODNA IZDAJA
– SIST HD 637 S1:1999, Elektroenergetske naprave nad 1 kV izmenične napetosti
OPOMBE
– Povsod, kjer se v besedilu standarda uporablja izraz “evropski standard”, v SIST EN 50522:2011
to pomeni “slovenski standard”.
– Nacionalni uvod in nacionalni predgovor nista sestavni del standarda.
– Ta nacionalni dokument je istoveten EN 50522:2010 in je objavljen z dovoljenjem
CEN/CENELEC
Upravni center
Avenue Marnix 17
B-1000 Bruselj
This national document is identical with EN 50522:2010 and is published with the permission of
CEN /CENELEC
Management Centre
Avenue Marnix 17
B -1000 Brussels
III
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SIST EN 50522 : 2011
IV
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EVROPSKI STANDARD EN 50522
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM november 2010
ICS 29.120.50 Nadomešča HD 637 S1:1999 (delno)
Slovenska izdaja
Ozemljitev elektroenergetskih postrojev, ki presegajo 1 kV izmenične napetosti
Earthing of power installations Prises de terre des installations Erdung von Starkstromanlagen mit
exceeding 1 kV a.c. électriques en courant alternatif de Nennwechselspannungen uber 1 kV
puissance supérieureŕ 1 kV
Ta evropski standard je CENELEC sprejel 1. novembra 2010. Člani CENELEC morajo izpolnjevati
notranje predpise CEN/CENELEC, ki določajo pogoje, pod katerimi dobi ta standard status
nacionalnega standarda brez kakršnih koli sprememb.
Najnovejši seznami teh nacionalnih standardov in njihovi bibliografski podatki se na zahtevo lahko
dobijo pri Centralnem sekretariatu ali katerem koli članu CENELEC.
Ta evropski standard obstaja v treh uradnih izdajah (angleški, francoski in nemški). Izdaje v drugih
jezikih, ki jih člani CENELEC na lastno odgovornost prevedejo in izdajo ter prijavijo pri Centralnem
sekretariatu, veljajo kot uradne izdaje.
Člani CENELEC so nacionalni organi za standarde Avstrije, Belgije, Bolgarije, Cipra, Češke republike,
Danske, Estonije, Finske, Francije, Grčije, Hrvaške, Islandije, Irske, Italije, Latvije, Litve,
Luksemburga, Madžarske, Malte, Nemčije, Nizozemske, Norveške, Poljske, Portugalske, Romunije,
Slovaške, Slovenije, Španije, Švedske, Švice in Združenega kraljestva.
CENELEC
Evropski komite za standardizacijo v elektrotehniki
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Upravni center: Avenue Marnix 17, B - 1000 Bruselj
© 2010 CENELEC Lastnice avtorskih pravic so vse države članice CENELEC Ref. oznaka EN 50522:2010 E
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SIST EN 50522 : 2011
Predgovor
Ta evropski standard je pripravil tehnični odbor CENELEC/TC 99X Elektroenergetski postroji, ki
presegajo 1 kV izmenične napetosti (1,5 kV enosmerne napetosti). Standard je bil predložen v
formalno glasovanje in ga je CENELEC sprejel 1. novembra 2010 kot EN 50522.
Ta dokument skupaj z EN 61936-1:2010 nadomešča HD 637 S1:1999.
Opozoriti je treba na možnost, da bi lahko bil kateri od elementov tega mednarodnega standarda
predmet patentnih pravic. CEN in CENELEC ne odgovarjata za identifikacijo nobene od teh patentnih
pravic.
Določena sta bila naslednja datuma:
– zadnji datum, do katerega mora EN dobiti status
nacionalnega standarda bodisi z objavo istovetnega
besedila ali z razglasitvijo (dop) 2011-11-01
– zadnji datum, ko je treba razveljaviti nacionalne
standarde, ki so z EN v nasprotju (dow) 2013-11-01
OPOMBA: Besedilo, ki je enako z IEC 61936-1, je zapisano poševno.
__________
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SIST EN 50522 : 2011
VSEBINA Stran
Predgovor . 2
1 Področje uporabe . 6
2 Zveze s standardi . 7
3 Izrazi in definicije . 7
3.1 Splošne definicije . 7
3.2 Definicije v zvezi s postroji . 8
3.3 Definicije v zvezi z varnostnimi ukrepi proti električnemu udaru. 9
3.4 Definicije v zvezi z ozemljitvijo . 9
4 Osnovne zahteve . 18
4.1 Splošne zahteve . 18
4.2 Električne zahteve . 18
4.3 Varnostna merila . 19
4.4 Funkcionalne zahteve . 20
5 Načrtovanje ozemljitvenih sistemov . 20
5.1 Splošno . 20
5.2 Dimenzioniranje glede na korozijo in mehansko trdnost . 20
5.3 Dimenzioniranje glede na toplotno obremenitev . 21
5.4 Dimenzioniranje glede na napetosti dotika . 22
6 Ukrepi za preprečitev prenosa potenciala . 27
6.1 Preneseni potencial z visokonapetostnega omrežja na nizkonapetostno omrežje . 27
6.2 Preneseni potenciali v telekomunikacijske in druge sisteme . 28
7 Gradnja ozemljitvenih sistemov . 29
7.1 Namestitev ozemljil in ozemljitvenih vodnikov . 29
7.2 Strela in prehodni pojavi. 29
7.3 Ukrepi za ozemljitev na opremi in napravah . 30
8 Meritve. 30
9 Vzdrževalnost . 30
9.1 Pregledi . 30
9.2 Meritve . 30
Dodatek A (normativni): Metoda izračuna dopustnih napetosti dotika . 31
Dodatek B (normativni): Napetost dotika in tok skozi telo . 32
B.1 Izračun dopustne napetosti dotika . 32
B.2 Izračun pričakovane dopustne napetosti dotika . 33
Dodatek C (normativni): Vrste materialov in najmanjše mere ozemljil, ki zagotavljajo mehansko
trdnost in korozijsko odpornost . 36
Dodatek D (normativni): Izračun tokovne obremenljivosti ozemljitvenih vodnikov in ozemljil . 37
Dodatek E (normativni): Opis priznanih posebnih ukrepov M . 41
Dodatek F (normativni): Ukrepi na ozemljitvenih sistemih za zmanjšanje vplivov
visokofrekvenčnega motenja . 43
Dodatek G (normativni): Posebni ukrepi za ozemljitev opreme in postrojev . 44
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SIST EN 50522 : 2011
G.1 Ograje okrog postrojev postaje . 44
G.2 Cevovodi . 44
G.3 Tračnice . 44
G.4 Jamborski transformatorski in/ali stikalni postroji . 44
G.5 Sekundarni tokokrogi instrumentnih transformatorjev . 45
Dodatek H (normativni): Meritve napetosti dotika . 46
Dodatek I (informativni): Redukcijski faktorji zaščitnih vrvi nadzemnih vodov in kovinskih
zaslonov podzemnih kablov . 47
I.1 Splošno . 47
I.2 Tipične vrednosti redukcijskih faktorjev za nadzemne vode in kable (50 Hz) . 47
Dodatek J (informativni): Osnove za načrtovanje ozemljitvenih sistemov. . 49
J.1 Upornost zemlje . 49
J.2 Upornost proti zemlji . 49
Dodatek K (informativni): Vgradnja ozemljil in ozemljitvenih vodnikov . 53
K.1 Vgradnja ozemljil . 53
K.2 Vgradnja ozemljitvenih vodnikov . 53
Dodatek L (informativni): Meritve za ozemljitvene sisteme in na njih . 55
L.1 Meritve upornosti zemlje . 55
L.2 Meritev upornosti proti zemlji in impedanc proti zemlji . 55
L.3 Določitev dviga ozemljitvenega potenciala . 56
L.4 Odpravljanje motenja in motilnih napetosti pri meritvah ozemljitve . 57
Dodatek M (normativni): Podrobnosti o gradbenem nadzoru in dokumentaciji
ozemljitvenih sistemov . 59
Dodatek N (informativni): Uporaba armaturnega jekla v betonu v ozemljitvene namene . 60
Dodatek O (informativni): Globalni ozemljitveni sistem . 61
Dodatek P (normativni): Posebni nacionalni pogoji . 62
Dodatek Q (informativni): A-deviacije . 63
Slika 1: Primer poteka potenciala na površini zemlje in napetosti, kadar skozi ozemljilo teče tok . 14
Slika 2: Primer tokov, napetosti in upornosti pri zemeljskem stiku v transformatorski postaji
z nizkoimpedančno ozemljitvijo nevtralne točke . 15
Slika 3: Bistvene komponente tokov zemeljskega stika v visokonapetostnih omrežjih . 17
Slika 4: Dopustna napetost dotika . 25
Slika 5: Načrtovanje ozemljitvenih sistemov, če niso del globalnega ozemljitvenega sistema
(5.4.2, C1), glede na dopustno napetost dotika U s preverjanjem dviga ozemljitvenega
Tp
potenciala U ali napetosti dotika U . . 26
E T
Slika B.1: Nadomestna shema za dotikalni tokokrog . 34
Slika B.2: Primeri krivulj UvTp= f (tf) pri različnih dodatnih upornostih RF = RF1 + RF2 . 35
Slika D.1: Gostota kratkostičnega toka G za ozemljitvene vodnike in ozemljila glede na trajanje
toka okvare tf . 38
Slika D.2: Trajni tok I za ozemljitvene vodnike . 40
D
Slika J.1: Upornost proti zemlji vodoravnih ozemljil (iz traku, okroglega materiala ali vrvi)
pri ravnem polaganju ali krožno v homogeni zemljini . 50
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SIST EN 50522 : 2011
Slika J.2: Upornost proti zemlji paličnih ozemljil, navpično zakopanih v homogeno zemljino . 51
Slika J.3: Tipične vrednosti za upornost proti zemlji kabla z ozemljitvenim učinkom v odvisnosti
od dolžine kabla in upornosti zemlje . 52
Slika L.1: Primer ugotavljanja impedance proti zemlji po tokovno-napetostni metodi . 58
Preglednica 1: Toki, ki se upoštevajo za načrtovanje ozemljitvenih sistemov . 22
Preglednica 2: Minimalne zahteve za medsebojno povezavo nizko- in visokonapetostnega
ozemljitvenega sistema na podlagi omejitve dviga ozemljitvenega potenciala (EPR) . 28
Preglednica B.1: Dopustni tok skozi telo IB v odvisnosti od trajanja okvare tf . 32
Preglednica B.2: Skupna impedanca človeškega telesa Z v odvisnosti od napetosti dotika U
T T
za pot toka od roke do roke . 33
Preglednica B.3: Izračunane vrednosti dopustne napetosti dotika U v odvisnosti
Tp
od trajanja okvare tf . 33
Preglednica B.4: Predpostavke za računanje z dodatnimi upornostmi . 33
Preglednica D.1: Konstante materialov . 37
Preglednica D.2: Faktorji za pretvorbo trajnega toka s končne temperature 300 ºC
na drugo končno temperaturo . 38
Preglednica E.1: Pogoji za uporabo priznanih posebnih ukrepov M za zagotovitev dopustnih
napetosti dotika UTp (glej sliko 4) . 41
Preglednica J.1: Upornosti zemlje za frekvence izmeničnih tokov (območje pogosto izmerjenih
vrednosti) . 49
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SIST EN 50522 : 2011
1 Področje uporabe
Ta evropski standard se uporablja pri določanju zahtev za načrtovanje in gradnjo ozemljitvenih
sistemov elektroenergetskih postrojev v omrežjih z nazivno napetostjo nad 1 kV izmenično in nazivno
frekvenco z vključno 60 Hz, da bi bilo zagotovljeno varno in primerno delovanje pri predvideni uporabi.
Za tolmačenje tega standarda se šteje, da je elektroenergetski postroj eden od naslednjih:
a) transformatorska postaja, vključno z železniškimi napajalnimi postajami,
b) električni postroj na stebru, drogu in stolpu; stikalna oprema in/ali transformatorji, postavljeni
zunaj zaprtega električnega obratovališča,
c) ena elektrarna (ali več elektrarn), postavljena(-e) na enem mestu; postroj vključuje generatorje in
transformatorje z vsemi pripadajočimi stikalnimi napravami in vsemi električnimi pomožnimi
sistemi. Povezave med postroji za proizvodnjo električne energije na različnih mestih so
izključene,
d) električno omrežje tovarne, industrijskega obrata ali drugih industrijskih, kmetijskih, obrtnih ali
javnih prostorov.
Elektroenergetski postroj vključuje, med drugim, naslednjo opremo:
– električne rotacijske stroje,
– stikalno opremo,
– transformatorje in dušilke,
– pretvornike,
– kable,
– sisteme ožičenja,
– baterije,
– kondenzatorje,
– ozemljitvene sisteme,
– stavbe in ograje, ki so del zaprtega električnega obratovališča,
– pripadajoče zaščitne, krmilne in pomožne sisteme,
– velike dušilke z zračnim jedrom.
OPOMBA: Na splošno ima standard za posamezno opremo prednost pred tem standardom.
Ta evropski standard se ne uporablja za načrtovanje in gradnjo ozemljitvenih sistemov za nobenega
od naslednjih:
– nadzemne in podzemne vode med krajevno ločenimi postroji,
– električne železnice,
– rudniško opremo in naprave,
– naprave s fluorescenčnimi sijalkami,
– naprave na ladjah in naprave na morju,
– elektrostatično opremo (npr. elektrostatične filtre, enote za lakiranje z brizganjem),
– preskuševališča,
– medicinsko opremo, npr. medicinsko rentgensko opremo.
Ta evropski standard se ne uporablja za zahteve za izvajanje montažnih del na električnih postrojih
pod napetostjo.
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2 Zveze s standardi
Spodaj navedeni standardi so nujno potrebni pri uporabi tega dokumenta. Pri datiranem sklicevanju
se upoštevajo samo navedene izdaje. Pri nedatiranem sklicevanju se upoštevajo zadnje izdaje
navedenih dokumentov (vključno s popravki in dopolnili).
EN 60529 Stopnje zaščite, ki jo zagotavlja ohišje (koda IP) (IEC 60529)
EN 60909 Kratkostični toki v trifaznih izmeničnih sistemih (IEC 60909)
HD 60364-1 Nizkonapetostne električne inštalacije – 1. del: Temeljna načela, ocena
splošnih karakteristik, definicije (IEC 60364-1:2005, spremenjen)
HD 60364-4-41 Nizkonapetostne električne inštalacije – 4-41. del: Zaščitni ukrepi – Zaščita
pred električnim udarom (IEC 60364-4-41:2005, spremenjen))
IEC 60050(151):2001 Mednarodni elektrotehniški slovar – Poglavje 151: Električne in magnetne
naprave
IEC 60050(195):1998 Mednarodni elektrotehniški slovar – Poglavje 195: Ozemljitev in zaščita pred
električnim udarom (in pri njem)
IEC 60050(601):1985 Mednarodni elektrotehniški slovar – Poglavje 601: Proizvodnja, prenos in
razdeljevanje elektrike – Splošno
IEC 60050(602):1983 Mednarodni elektrotehniški slovar – Poglavje 602: Proizvodnja, prenos in
razdeljevanje elektrike – Proizvodnja
IEC 60050(604):1987 Mednarodni elektrotehniški slovar – Poglavje 604: Proizvodnja, prenos in
razdeljevanje elektrike – Obratovanje
IEC 60050(605):1983 Mednarodni elektrotehniški slovar – Poglavje 605: Proizvodnja, prenos in
razdeljevanje elektrike – Postaje
IEC 60050(826):2004 Mednarodni elektrotehniški slovar – 826. del: Električne inštalacije
IEC 60287-3-1 Električni kabli – Izračun tokovne obremenljivosti – 3-1. del: Sekcije za
obratovalne pogoje – Referenčni obratovalni pogoji in izbira tipa kabla
IEC/TS 60479-1:2005 Vplivi električnega toka na človeka in živali – 1. del: Splošno
IEC 60949:1988 Izračun toplotno dopustnega kratkostičnega toka, upoštevaje neadiabatno
segrevanje
IEC/TS 61000-5-2 Elektromagnetna združljivost (EMC) – 5. del: Smernice za namestitev in
ublažitev – 2. razdelek: Ozemljevanje in kabljenje
3 Izrazi in definicije
V tem dokumentu se uporabljajo naslednji izrazi in definicije.
3.1 Splošne definicije
3.1.1
električna oprema
predmet, ki se uporablja za proizvodnjo, pretvarjanje, prenos, razdeljevanje ali uporabo električne
energije, kot so (električni) stroji, transformatorji, stikalne in krmilne naprave, merilni instrumenti, zaščitne
naprave, oprema za inštalacijski sistem in električni porabniki
[IEV 826-16-01]
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SIST EN 50522 : 2011
3.1.2
naznačena vrednost
vrednost veličine, ki se uporablja za navajanje specifikacij in ustreza določenemu naboru obratovalnih
pogojev za sestavni del, napravo, opremo ali sistem
[IEV 151-16-08]
3.13
visoka napetost
izmenična napetost, ki presega 1 000 V
3.1.4
nizka napetost
izmenična napetost, ki ne presega 1 000 V
3.1.5
obratovanje
vse dejavnosti, vključno z električnimi in tudi neelektričnimi, ki so potrebne za funkcioniranje
elektroenergetskega postroja
OPOMBA: Te dejavnosti vključujejo preklapljanje, krmiljenje, spremljanje in vzdrževanje.
3.2 Definicije v zvezi s postroji
3.2.1
zaprto električno obratovališče
prostor ali lokacija za obratovanje električnih postrojev in opreme, do katere je dostop omejen in
dovoljen samo strokovnim ali poučenim osebam ali osebam pod nadzorom strokovnih ali poučenih
oseb, npr. z odprtjem vrat ali z odstranitvijo zaščitne pregrade samo z uporabo ključa ali ustreznega
orodja, in ki je jasno označena z ustreznimi opozorilnimi znaki
3.2.2
postaja
del električnega omrežja, ki zaseda določen prostor in vsebuje v glavnem priključke prenosnih ali
distribucijskih vodov, stikalne aparate in ohišja, ki lahko vsebujejo transformatorje. Na splošno vsebuje
postrojenja za varnost in vodenje omrežja (npr. zaščitne naprave)
OPOMBA: Predpona lahko določa transformatorsko postajo glede na vrsto omrežja, v katero je vključena.
PRIMER: Prenosna postaja (prenosnega omrežja), razdelilna (distribucijska) postaja, 400 kV postaja, 20 kV postaja.
[IEV 605-01-01]
3.2.3
elektrarna
postroj za proizvodnjo elektrike, ki obsega gradbene objekte, opremo za pretvarjanje energije in vso
potrebno pomožno opremo
[IEV 602-01-01]
3.2.4
postroji odprte izvedbe
postroji, kjer oprema ni zaščitena pred neposrednim dotikom
3.2.5
postroji zaprte izvedbe
postroji, kjer je oprema zaščitena pred neposrednim dotikom
OPOMBA: Za stopnje zaščite ohišij glej EN 60529.
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SIST EN 50522 : 2011
3.3 Definicije v zvezi z varnostnimi ukrepi proti električnemu udaru
3.3.1
zaščita pred neposrednim dotikom
ukrepi, ki preprečujejo osebam, da bi z deli svojih teles ali predmetov prišle v nevarno bližino delov
pod napetostjo ali tistih delov, ki bi lahko bili pod nevarno napetostjo (doseganje nevarnega območja)
3.3.2
zaščita pri posrednem dotiku
zaščita oseb pred nevarnostjo, ki lahko nastane ob okvari zaradi stika z izpostavljenimi prevodnimi
deli električne opreme ali tujimi prevodnimi deli
3.3.3
ohišje
del, ki zagotavlja zaščito opreme pred določenimi zunanjimi vplivi in v vseh smereh zaščito pred
neposrednim dotikom
3.4 Definicije v zvezi z ozemljitvijo
3.4.1
(okolna) zemlja
del Zemlje, ki je v električnem stiku z ozemljilom in katerega električni potencial ni nujno enak nič
OPOMBA: Prevodna masa zemlje, za katero se električni potencial v kateri koli točki dogovorno šteje, da je enak nič.
[IEV 195-01-03, spremenjeno]
3.4.2
referenčna zemlja
(oddaljena zemlja)
del Zemlje, ki se obravnava kot prevoden, katerega električni potencial je po dogovoru nič in je zunaj
vplivnega območja drugih ozemljitvenih naprav
OPOMBA: Pojem Zemlja pomeni planet in vse njegove fizikalne zadeve.
[IEV 195-01-01, spremenjeno]
3.4.3
ozemljilo
prevodni del, ki je lahko zakopan v poseben prevodni medij, npr. beton ali zemljino, in je v električnem
stiku z Zemljo
[IEV 195-02-01]
3.4.4
ozemljitveni vodnik
vodnik, ki zagotavlja prevodno pot ali del prevodne poti med dano točko v omrežju ali v inštalaciji ali v
opremi in ozemljilom
[IEV 195-02-03]
OPOMBA: Kjer je povezava med delom inštalacije in ozemljilom izvedena z ločljivo povezavo, ločilnom stikalom, števcem
odvedenih prenapetosti, iskrilom prenapetostnega odvodnika itd., je ozemljitveni vodnik samo tisti del
povezave, ki je trajno povezan z ozemljilom.
3.4.5
vodnik za zaščitno izenačitev potencialov
zaščitni vodnik, ki zagotavlja izenačitev potencialov
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SIST EN 50522 :
...
SLOVENSKI STANDARD
oSIST prEN 50522:2008
01-december-2008
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Earthing of power installations exceeding 1 kV a.c.
Erdung von Starkstromanlagen mit Nennwechselspannungen über 1 kV
Prises de terre des installations électriques en courant alternatif de puissance supérieure
à 1 kV
Ta slovenski standard je istoveten z: prEN 50522:2008
ICS:
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
oSIST prEN 50522:2008 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 50522:2008
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oSIST prEN 50522:2008
DRAFT
EUROPEAN STANDARD
prEN 50522
NORME EUROPÉENNE
October 2008
EUROPÄISCHE NORM
ICS Will supersede HD 637 S1:1999 (partially)
English version
Earthing of power installations exceeding 1 kV a.c.
Prises de terre des installations Erdung von Starkstromanlagen mit
électriques en courant alternatif de Nennwechselspannungen über 1 kV
puissance supérieure à 1 kV
This draft European Standard is submitted to CENELEC members for CENELEC enquiry.
Deadline for CENELEC: 2009-03-13.
It has been drawn up by CLC/TC 99X.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CENELEC 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 Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, 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.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to
change without notice and shall not be referred to as a European Standard.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Project: 16819 Ref. No. prEN 50522:2008 E
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prEN 50522:2008 – 2 –
1 Foreword
2
3 This draft European Standard was prepared by the Technical Committee CENELEC TC 99X,
4 Power installations exceeding 1 kV a.c. (1,5 kV d.c.). It is submitted to the CENELEC enquiry.
5
CLC/TC 99X note:
This draft European Standard is circulated simultaneously with the parallel vote on future
IEC 61936-1 (99/81/CDV).
The text identical with IEC 61936-1 / MT 4 is written in italics.
6
7 __________
8
9
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10 Contents
11 1 Scope . 6
12 2 Normative re f e r enc es . 7
13 3 Definitions . 8
14 3.1 General . 8
15 3.2 Installations . 8
16 3.3 Safety measures against electric s hoc k . 9
17 3.4 Earthing . 9
18 4 Fundamental requirements . 17
19 4.1 General . 17
20 4.2 Electrical requirements . 18
21 4.3 Safety criteria . 19
22 4.4 Functional requirements . 19
23 5 Design of earthing systems . 20
24 5.1 General . 20
25 5.2 Dimensioning with respect to corrosion and mechanical strength . 20
26 5.3 Dimensioning with respect to thermal strength . 21
27 5.4 Dimensioning with regard to touch and step voltages . 23
28 6 Measures to avoid transferred pot ential . 27
29 6.1 Transferred potential from High voltage systems to Low voltage systems . 27
30 6.2 Transferred potentials to telecommunication and other systems . 28
31 7 Construction of earthing systems . 29
32 7.1 Installation of earth electrodes and earthing conductors . 29
33 7.2 Lightning and tr ans ients . 29
34 7.3 Measures for earthing on equipment and installations . 30
35 8 Measurements and documentation . 30
36 9 Maintainability . 30
37 9.1 Inspections . 30
38 9.2 Measurements . 30
39 Annex A (normative) Method of calculating the voltage limit . 31
40 Annex B (normative) Touch voltage and body current . 32
41 B.1 Equivalence between touch voltage and body current . 32
42 B.2 Taking into account additional resistances . 33
43 Annex C (normative) Type and minimum dimensions of earth electrode materials
44 ensuring mechanical strength and corrosion resistance . 36
45 Annex D (normative) Current rating calculation of earthing conductors and earth
46 electrodes . 37
47 Annex E (normative) Description of the recognized specified measures M . 41
48 Annex F (normative) Measures on earthing systems to reduce the effects of high
49 frequency interference . 44
50 Annex G (normative) Detailed measures for earthing of equipment and installations . 45
51 G.1 Fences around substation installa tions . 45
52 G.2 Pipes . 45
53 G.3 Traction rails . 45
54 G.4 Pole mounted transforming and/or switching installations . 45
55 G.5 Secondary circuits of instrument transformers . 46
56 Annex H (normative) Measuring touch voltages . 47
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57 Annex I (informative) Reduction factors related to earth wires of overhead lines and
58 metal sheaths of underground cables . 48
59 I.1 General . 48
60 I.2 Typical values of reduction factors of overhead lines and cables (50 Hz) . 48
61 Annex J (informative) Basis for the design of earthing systems . 50
62 J.1 Soil resistivity . 50
63 J.2 Resistance to earth . 50
64 Annex K (informative) Installing the earth electrodes and earthing conductors . 54
65 K.1 Installation of earth electrodes . 54
66 K.2 Installation of earthing conductors . 54
67 Annex L (informative) Measurements for and on earthing systems . 56
68 L.1 Measurement of soil resistivities . 56
69 L.2 Measurement of resistances to earth and impedances to earth . 56
70 L.3 Determination of the earth potential rise . 57
71 L.4 Elimination of interference and disturbance voltages for earthing
72 m eas ur em ents . 58
73 Annex M (normative) Details on site inspection and documentation of earthing systems . 61
74 Annex N (informative) The use of reinforcing bars in concrete for earthing purpose . 62
75 Annex O (informative) Global Earthing System . 63
76
77 Figure 1 - Example for the surface potential profile and for the voltages in case of
78 current carrying earth electrodes . 14
79 Figure 2 - Example for currents, voltages and resistances for an earth fault in a
80 transformer substation with low impedance neutral earthing . 15
81 Figure 3 - Essential components of earth fault currents in high voltage systems . 17
82 Figure 4 - Touch voltage limit . 25
83 Figure 5 - Design of earthing systems, if not part of a global earthing system (C1 of
84 5.4.2 ), with regard to permissible touch voltage UTp by checking the earth potential rise
85
UE or the touch voltage UT . 26
86 Figure B.1 - Scheme of the touching circuit . 34
87 Figure B.2 - Examples for curves USTp = f (t ) for different additional resistances
F
88 R = R + R . 35
a a1 a2
89 Figure D.1 - Short circuit current density G for earthing conductors and earth electrodes
90 relative to the duration of the fault current t . 38
F
91 Figure D.2 - Continuous current I for earthing conductors . 40
D
92 Figure J.1 - Resistance to earth of horizontal earth electrodes (made from strip, round
93
material or stranded conductor) for straight or ring arrangement in homogeneous soil . 51
94 Figure J.2 - Resistance to earth of earth rods, vertically buried in homogeneous soil . 52
95 Figure J.3 - Typical values for the resistance to earth of a cable with earth electrode
96 effect depending on the length of the cable and the soil r e s i s t ivity . 53
97 Figure L.1 - Example for the determination of the impedance to earth by the heavy-
98 current injection method . 60
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99
100 Table 1 - Relevant currents for the design of earthing systems . 22
101 Table 2 - Minimum requirements for interconnection of low voltage and high voltage
102 earthing systems based on EPR limits . 28
103 Table B.1 - Permissible body current I depending on the fault duration t . 32
B F
104 Table B.2 - Total human body impedance Z related to the touch voltage U for a current
B T
105 path hand to hand or hand to foot . 32
106 Table B.3 - Calculated values of the permissible touch voltage U as a function of the
Tp
107 fault duration t . 33
F
108 Table B.4 - Assumption for calculations with additional resistances . 33
109
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110 1 Scope
111 This European Standard contains the requirements for the design and erection of earthing
112 systems of electrical installations, in systems with nominal voltage above 1 kV a.c., so as to
113 provide safety and proper functioning for the use intended.
114 For the purpose of interpreting this standard, an electrical power installation is considered to be
115 one of the following.
116 a) Substation.
117 b) Electrical installations on mast, pole and tower.
118 Switchgear and/or transformers located outside a closed electrical operating area.
119 c) One (or more) power station(s) located on a single site.
120 The installation includes generators and transformers with all associated switchgear and all
121 electrical auxiliary systems. Connections between generating stations located on different
122 sites are excluded.
123 d) The electrical system of a factory, industrial plant or other industrial, agricultural,
124 commercial or public premises.
125 The electrical power installation includes, among others, the following equipment:
126 – rotating electrical machines;
127 – switchgear;
128 – transformers and reactors;
129 – converters;
130 – cables;
131 – wiring systems;
132 – batteries;
133 – capacitors;
134 – earthing systems;
135 – buildings and fences which are part of a closed electrical operating area;
136 – associated protection, control and auxiliary systems;
137 – large air core reactor.
138 NOTE In general, a standard for an item of equipment takes precedence over this standard.
139 This European Standard does not apply to the design and erection of earthing systems of any
140 of the following:
141 – overhead and underground lines between separate installations;
142 – electric railways (but not the substation feeding a railway system);
143 – mining equipment and installations;
144 – fluorescent lamp installations;
145 – installations on ships and off-shore installations;
146 – electrostatic equipment (e.g. electrostatic precipitators, spray-painting units);
147 – test sites;
148 – medical equipment, e.g. medical X-ray equipment.
149 This European Standard does not apply to the requirements for carrying out live working on
150 electrical installations.
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151 2 Normative references
152 The following referenced documents are indispensable for the application of this document. For
153 dated references, only the edition cited applies. For undated references, the latest edition of
154 the referenced document (including any amendments) applies.
155 EN 60529, Degrees of protection provided by enclosures (IP Code) (IEC 60529)
156 EN 60909, Short-circuit currents in three-phase a.c. systems (IEC 60909)
157 HD 60364-1, Low-voltage electrical installations – Part 1: Fundamental principles, assessment
158 of general characteristics, definitions (IEC 60364-1, modified)
159 HD 60364-4-41, Low-voltage electrical installations – Part 4-41: Protection for safety –
160 Protection against electric shock (IEC 60364-4-41, modified)
161 IEC 60050(151):2001, International Electrotechnical Vocabulary (IEV) – Part 151: Electrical
162 and magnetic devices
163 IEC 60050(195):1998, International Electrotechnical Vocabulary (IEV) – Part 195: Earthing and
164 protection against electric shock
165 IEC 60050(601):1985, International Electrotechnical Vocabulary (IEV) – Part 601: Generation,
166 transmission and distribution of electricity – General
167 IEC 60050(602):1983, International Electrotechnical Vocabulary (IEV) –Part 602: Generation,
168 transmission and distribution of electricity – Generation
169 IEC 60050(604):1987, International Electrotechnical Vocabulary (IEV) – Part 604: Generation,
170 transmission and distribution of electricity – Operation
171 IEC 60050(605):1983, International Electrotechnical Vocabulary (IEV) – Part 605: Generation,
172 transmission and distribution of electricity – Substations
173 IEC 60050(826):2004, International Electrotechnical Vocabulary (IEV) – Part 826: Electrical
174 installations
175 IEC 60287-3-1, Electric cables – Calculation of the current rating – Part 3-1: Sections on
176 operating conditions – Reference operating conditions and selection of cable type
177 IEC/TS 60479-1:2005, Effects of current on human beings and livestock – Part 1: General
178 aspects
179 IEC 60949:1988, Calculation of thermally permissible short-circuit currents, taking into account
180 non-adiabatic heating effects
181 IEC 61000-5-2, Electromagnetic compatibility (EMC) – Part 5: Installation and mitigation
182 guidelines – Section 2: Earthing and cabling
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183 3 Definitions
184 For the purposes of this document, the following terms and definitions apply.
185 3.1 General
186 3.1.1
187 electrical equipment
188 any item used for such purposes as generation, conversion, transmission, distribution and
189 utilization of electrical energy, such as machines, transformers, apparatus, measuring
190 instruments, protective devices, equipment for wiring systems, appliances
191 [IEV 826-07-01]
192 3.1.2
193 rated value
194 value of a quantity used for specification purposes, established for a specified set of operating
195 conditions of a component, device, equipment, or system
196 [IEV 151-16-08]
197 3.1.3
198 high voltage
199 voltage exceeding 1 000 V a.c.
200 3.1.4
201 low voltage
202 voltage not exceeding 1 000 V a.c.
203 3.1.5
204 operation
205 all activities, including both electrical and non-electrical work activities, necessary to permit the
206 power installation to function. These activities include switching, controlling, monitoring and
207 maintenance
208 3.2 Installations
209 3.2.1
210 closed electrical operating area
211 room or location for operation of electrical installations and equipment to which access is
212 intended to be restricted to skilled or instructed persons or to lay personnel under the
213 supervision of skilled or instructed persons, e.g. by opening of a door or removal of protective
214 barrier only by the use of a key or tool, and which is clearly marked by appropriate warning
215 signs
216 3.2.2
217 substation
218 part of a power system, concentrated in a given place, including mainly the terminations of
219 transmission or distribution lines, switchgear and housing and which may also include
220 transformers. It generally includes facilities necessary for system security and control (e.g. the
221 protective devices)
222 EXAMPLES: transmission substation (of a transmission system), distribution substation, 400 kV substation, 20 kV
223 substation.
224 [IEV 605-01-01]
225 NOTE According to the nature of the system within which the substation is included, a prefix may qualify it.
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226 3.2.3
227 power station
228 installation whose purpose is to generate electricity and which includes civil engineering works,
229 energy conversion equipment and all the necessary ancillary equipment
230 [IEV 602-01-01]
231 3.2.4
232 installations of open design
233 installations where the equipment does not have protection against direct contact
234 3.2.5
235 installations of enclosed design
236 installations where the equipment has protection against direct contact
237 NOTE For degrees of enclosure protection see EN 60529.
238
239 3.3 Safety measures against electric shock
240 3.3.1
241 protection against direct contact
242 measures which prevent persons coming into hazardous proximity to live parts or those parts
243 which could carry a hazardous voltage, with parts of their bodies or objects (reaching the
244 danger zone)
245 3.3.2
246 protection in case of indirect contact
247 protection of persons from hazards which could arise, in event of fault, from contact with
248 exposed conductive parts of electrical equipment or extraneous conductive parts
249 3.3.3
250 enclosure
251 part providing protection of equipment against certain external influences and, in any direction,
252 protection against direct contact
253 [IEV 826-03-12]
254
255 3.4 Earthing
256 3.4.1
257 (local) earth
258 part of the Earth which is in electric contact with an earth electrode and the electric potential of
259 which is not necessarily equal to zero
260 NOTE The conductive mass of the earth, whose electric potential at any point is conventionally taken as equal to
261 zero.
262 [IEV 195-01-03]
263 3.4.2
264 reference earth
265 (remote earth)
266 part of the Earth considered as conductive, the electric potential of which is conventionally
267 taken as zero, being outside the zone of influence of the relevant earthing arrangement
268 NOTE The concept “Earth” means the planet and all its physical matter.
269 [IEV 195-01-01, modified]
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270 3.4.3
271 earth electrode
272 conductive part, which is in electric contact with the earth and which may be embedded in a
273 specific conductive medium, e.g. in concrete
274 [IEV 195-02-01]
275 3.4.4
276 earthing conductor
277 conductor which provides a conductive path, or part of the conductive path, between a given
278 point in a system or in an installation or in equipment and an earth electrode
279 [IEV 195-02-03]
280 NOTE Where the connection between part of the installation and the earth electrode is made via a disconnecting
281 link, disconnecting switch, surge arrester counter, surge arrester control gap etc., then only that part of the
282 connection permanently attached to the earth electrode is an earthing conductor.
283 3.4.5
284 protective bonding conductor
285 protective conductor for ensuring equipotential bonding
286 [IEV 826-04-10, modified]
287 3.4.6
288 earthing system
289 arrangement of connections and devices necessary to earth equipment or a system separately
290 or jointly
291 [IEV 604-04-02]
292 3.4.7
293 earth rod
294 earth electrode consisting of a metal rod driven into the ground
295 [IEV 604-04-09]
296 3.4.8
297 structural earth electrode
298 metal part, which is in conductive contact with the earth or with water directly or via concrete,
299 whose original purpose is not earthing, but which fulfils all requirements of an earth electrode
300 without impairment of the original purpose
301 NOTE Examples of structural earth electrodes are pipelines, sheet piling, concrete reinforcement bars in
302 foundations and the steel structure of buildings, etc.
303 3.4.9
304 electric resistivity of soil, ρ
S
305 resistivity of a typical sample of soil
306 3.4.10
307 resistance to earth, R
E
308 real part of the impedance to earth
309 3.4.11
310 impedance to earth, Z
E
311 impedance at a given frequency between a specified point in a system or in an installation or in
312 equipment and reference earth
313 NOTE The impedance to earth is determined by the directly connected earth electrodes and also by connected
314 overhead earth wires and wires buried in earth of overhead lines, by connected cables with earth electrode effect
315 and by other earthing systems which are conductively connected to the relevant earthing system by conductive
316 cable sheaths, shields, PEN conductors or in another way.
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317 3.4.12
318 earth potential rise, EPR
319 voltage between an earthing system and reference earth
320 3.4.13
321 potential
322 voltage between an observation point and reference earth
323 3.4.14
324 (effective) touch voltage, U
T
325 voltage between conductive parts when touched simultaneously
326 NOTE The value of the effective touch voltage may be appreciably influenced by the impedance of the person in
327 electric contact with these conductive parts.
328 [IEV 195-05-11, modified]
329 3.4.15
330 prospective touch voltage (source voltage for touching)
331 voltage between simultaneously accessible conductive parts when those conductive parts are
332 not being touched
333 [IEV 195-05-09, modified]
334 3.4.16
335 step voltage, U
S
336 voltage between two points on the earth’s surface that are 1 m distant from each other, which
337 is considered to be the stride length of a person
338 [IEV 195-05-12]
339 3.4.17
340 transferred potential
341 potential rise of an earthing system caused by a current to earth transferred by means of a
342 connected conductor (for example a metallic cable sheath, PEN conductor, pipeline, rail) into
343 areas with low or no potential rise relative to reference earth resulting in a potential difference
344 occurring between the conductor and its surroundings (Figure 1).
345 NOTE The definition also applies where a conductor, which is connected to reference earth, leads into the area
346 of the potential rise.
347 3.4.18
348 stress voltage
349 voltage appearing during earth fault conditions between an earthed part or enclosure of
350 equipment or device and any other of its parts and which could affect its normal operation or
351 safety
352 3.4.19
353 global earthing system
354 equivalent earthing system created by the interconnection of local earthing systems that
355 ensures, by the proximity of the earthing systems, that there are no dangerous touch voltages.
356 Such systems permit the division of the earth fault current in a way that results in a reduction of
357 the earth potential rise at the local earthing system. Such a system could be said to form a
358 quasi equipotential surface
359 NOTE The existence of a global earthing system may be determined by sample measurements or calculation for
360 typical systems. Typical examples of global earthing systems are in city centres; urban or industrial areas with
361 distributed low- and high-voltage earthing (see Annex O).
362 3.4.20
363 multi-earthed HV neutral conductor
364 neutral conductor of a distribution line connected to the earthing system of the source
365 transformer and regularly earthed
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366 3.4.21
367 exposed conductive part
368 conductive part of equipment which can be touched and which is not normally live, but which
369 can become live when basic insulation fails
370 [IEV 826-03-02, modified]
371 3.4.22
372 extraneous con
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