EN 61400-24:2010

Wind turbines - Part 24: Lightning protection

Identifies the generic problems involved in lightning protection of wind turbines; describes appropriate methods for evaluating the risk of lightning damage to wind turbines; describes and outlines suitable methods for lightning protection of wind turbine components.

Windenergieanlagen - Teil 24: Blitzschutz

Eoliennes - Partie 24: Protection contre la foudre

Vetrne turbine - 24. del: Zaščita pred delovanjem strele (IEC 61400-24:2010)

Ta mednarodni standard velja za zaščito generatorjev vetrnih turbin in sistemov na veter pred delovanjem strele. Normativno se sklicuje na splošne standarde za zaščito pred delovanjem strele za nizkonapetostne in visokonapetostne sisteme za stroje in instalacije ter za elektromagnetno skladnost(EMC). Ta standard opredeljuje okolje delovanja strele za vetrne turbine in uporabo okolja za oceno tveganja za vetrne turbine. Opredeljuje zahteve za zaščito lopatic, drugih strukturnih sestavnih delov ter električnih in nadzornih sistemov pred neposrednimi in posrednimi učinki delovanja strele. Priporočene so preskusne metode za validacijo skladnosti.  Podano je vodilo o uporabi veljavne zaščite pred delovanjem strele ter industrijskih električnih in EMC standardov, vključno z ozemljitvijo. Podano je vodilo v zvezi z osebno varnostjo. Podane so smernice za statistiko in poročanje o poškodbah.

General Information

• Status: Withdrawn
• Publication Date: 08-Jul-2010
• Withdrawal Date: 30-Jun-2013
• ICS: 27.180 - Wind turbine energy systems
• Technical Committee: CLC/TC 88 - Wind turbines
• Drafting Committee: IEC/TC 88 - IEC_TC_88
• Parallel Committee: IEC/TC 88 - IEC_TC_88
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 07-Aug-2022
• Completion Date: 07-Aug-2022
• Ref Project: SIST EN 61400-24:2010 - Wind turbines - Part 24: Lightning protection (IEC 61400-24:2010)

Relations

• Replaced By: EN IEC 61400-24:2019 - Wind energy generation systems - Part 24: Lightning protection
• Effective Date: 20-Dec-2016

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2010
9HWUQHWXUELQHGHO=DãþLWDSUHGGHORYDQMHPVWUHOH,(&
Wind turbines - Part 24: Lightning protection (IEC 61400-24:2010)
Windenergieanlagen - Teil 24: Blitzschutz (IEC 61400-24:2010)
Eoliennes - Partie 24: Protection contre la foudre (CEI 61400-24:2010)
Ta slovenski standard je istoveten z: EN 61400-24:2010
ICS:
27.180 Sistemi turbin na veter in Wind turbine systems and
drugi alternativni viri energije other alternative sources of
energy
91.120.40 =DãþLWDSUHGVWUHOR Lightning protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 61400-24
NORME EUROPÉENNE
July 2010
EUROPÄISCHE NORM
ICS 27.180
English version
Wind turbines -
Part 24: Lightning protection
(IEC 61400-24:2010)
Eoliennes -  Windenergieanlagen -
Partie 24: Protection contre la foudre Teil 24: Blitzschutz
(CEI 61400-24:2010) (IEC 61400-24:2010)

This European Standard was approved by CENELEC on 2010-07-01. 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 61400-24:2010 E
Foreword
The text of document 88/366/FDIS, future edition 1 of IEC 61400-24, prepared by IEC TC 88, Wind
turbines, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as
EN 61400-24 on 2010-07-01.
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) 2011-04-01
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2013-07-01
with the EN have to be withdrawn
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61400-24:2010 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 61400-24:2010
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

- - Power installations exceeding 1 kV a.c. HD 637 S1 1999
+ corr. June 2005
- - Lightning Protection Components (LPC) - EN 50164-1 -
Part 1: Requirements for connection
components
IEC 60060-1 1989 High-voltage test techniques - HD 588.1 S1 1991
Part 1: General definitions and test
requirements
IEC 60068 Series Environmental testing EN 60068 Series

IEC 60071 Series Insulation co-ordination EN 60071 Series

IEC 60071-2 1996 Insulation co-ordination - EN 60071-2 1997
Part 2: Application guide
IEC 60099-4 - Surge arresters - EN 60099-4 -
Part 4: Metal-oxide surge arresters without
gaps for a.c. systems
IEC 60099-5 - Surge arresters - EN 60099-5 -
Part 5: Selection and application
recommendations
IEC 60204-1 - Safety of machinery - Electrical equipment of EN 60204-1 -
machines -
Part 1: General requirements
IEC 60204-11 - Safety of machinery - Electrical equipment of EN 60204-11 -
machines -
Part 11: Requirements for HV equipment for
voltages above 1 000 V a.c. or 1 500 V d.c.
and not exceeding 36 kV
IEC 60243-1 - Electrical strength of insulating materials - EN 60243-1 -
Test methods -
Part 1: Tests at power frequencies

IEC 60243-3 - Electrical strength of insulating materials - EN 60243-3 -
Test methods -
Part 3: Additional requirements for 1,2/50 µs
impulse tests
IEC 60364-4-44 - Low voltage electrical installations - HD 60364-4-444 -
Part 4-44: Protection for safety - Protection
against voltage disturbances and
electromagnetic disturbances
Publication Year Title EN/HD Year

IEC 60364-5-53 2001 Electrical installations of buildings - - -
+ A1 (mod) 2002 Part 5-53: Selection and erection of electrical
equipment - Isolation, switching and control

IEC 60464-2 - Varnishes used for electrical insulation - EN 60464-2 -
Part 2: Methods of test
IEC/TS 60479-1 - Effects of current on human beings and - -
livestock -
Part 1: General aspects
IEC/TR 60479-4 - Effects of current on human beings and - -
livestock -
Part 4: Effects of lightning strokes on human
beings and livestock
IEC 60587 - Electrical insulating materials used under EN 60587 -
severe ambient conditions - Test methods for
evaluating resistance to tracking and erosion

IEC 60664-1 - Insulation coordination for equipment within EN 60664-1 -
low-voltage systems -
Part 1: Principles, requirements and tests

IEC 61000-4-5 - Electromagnetic compatibility (EMC) - EN 61000-4-5 -
Part 4-5: Testing and measurement
techniques - Surge immunity test

IEC/TR 61000-5-2 - Electromagnetic compatibility (EMC) - - -
Part 5: Installation and mitigation guidelines -
Section 2: Earthing and cabling

IEC/TS 61400-23 - Wind turbine generator systems - - -
Part 23: Full-scale structural testing of rotor
blades
IEC 61643-1 - Low-voltage surge protective devices - - -
Part 1: Surge protective devices connected to
low-voltage power distribution systems -
Requirements and tests
IEC 61643-12 - Low-voltage surge protective devices - CLC/TS 61643-12 -
Part 12: Surge protective devices connected
to low-voltage power distribution systems -
Selection and application principles

IEC 61643-21 - Low voltage surge protective devices - EN 61643-21 -
Part 21: Surge protective devices connected
to telecommunications and signalling
networks - Performance requirements and
testing methods
IEC 61643-22 - Low-voltage surge protective devices - CLC/TS 61643-22 -
Part 22: Surge protective devices connected
to telecommunications and signalling
networks - Selection and application principles

IEC 62153-4-3 - Metallic communication cable test methods - - -
Part 4-3: Electromagnetic Compatibility
(EMC) - Surface transfer impedance - Triaxial
method
IEC 62305-1 2006 Protection against lightning - EN 62305-1 2006
Part 1: General principles + corr. November 2006

IEC 62305-2 2006 Protection against lightning - EN 62305-2 2006
Part 2: Risk management + corr. November 2006

- 5 - EN 61400-24:2010
Publication Year Title EN/HD Year

IEC 62305-3 (mod) 2006 Protection against lightning - EN 62305-3 2006
- - Part 3: Physical damage to structures and + corr. September 2008
life hazard + corr. November 2006
+ A11 2009
IEC 62305-4 2006 Protection against lightning - EN 62305-4 2006
Part 4: Electrical and electronic systems + corr. November 2006
within structures
ITU-T - Resistibility of telecommunication equipment - -
Recommendation installed in a telecommunications centre to
K.20 overvoltages and overcurrents

ITU-T - Resistibility of telecommunication equipment - -
Recommendation installed in customer premises to overvoltages
K.21 and overcurrents
ITU-T - Protection of telecommunication lines using - -
Recommendation metallic symmetric conductors against
K46 lightning-induced surges
IEC 61400-24 ®
Edition 1.0 2010-06
INTERNATIONAL
STANDARD
Wind turbines –
Part 24: Lightning protection
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XG
ICS 27.180 ISBN 978-2-88910-969-2
– 2 – 61400-24 © IEC:2010(E)
CONTENTS
FOREWORD.8
1 Scope.10
2 Normative references .10
3 Terms and definitions .12
4 Symbols and units .18
5 Abbreviations .20
6 Lightning environment for wind turbine .20
6.1 General .20
6.2 Lightning current parameters and lightning protection levels (LPL) .20
7 Lightning exposure assessment.22
7.1 General .22
7.2 Assessing the frequency of lightning affecting a wind turbine .23
7.3 Assessing the risk of damage.26
7.3.1 Basic equation.26
7.3.2 Assessment of risk components due to flashes to the wind turbine
(S1) .27
7.3.3 Assessment of the risk component due to flashes near the wind
turbine (S2) .27
7.3.4 Assessment of risk components due to flashes to a service line
connected to the wind turbine (S3) .27
7.3.5 Assessment of risk component due to flashes near a service line
connected to the wind turbine (S4) .28
8 Lightning protection of subcomponents.29
8.1 General .29
8.2 Blades.29
8.2.1 General .29
8.2.2 Requirements .29
8.2.3 Verification .29
8.2.4 Protection design considerations .30
8.2.5 Test methods.32
8.3 Nacelle and other structural components.32
8.3.1 General .32
8.3.2 Hub .33
8.3.3 Spinner.33
8.3.4 Nacelle .33
8.3.5 Tower .34
8.3.6 Testing methods .34
8.4 Mechanical drive train and yaw system.34
8.4.1 General .34
8.4.2 Bearings.35
8.4.3 Hydraulic systems .35
8.4.4 Spark gaps and sliding contacts .35
8.4.5 Testing .35
8.5 Electrical low-voltage systems and electronic systems and installations .36
8.5.1 General .36
8.5.2 LEMP protection measures (LPMS) .36
8.5.3 Lightning protection zones (LPZ) .37

61400-24 © IEC:2010(E) – 3 –
8.5.4 Equipotential bonding within the wind turbine .37
8.5.5 Shielding and line routing .37
8.5.6 Coordinated SPD protection .38
8.5.7 Testing methods for system immunity tests.41
8.6 Electrical high-voltage (HV) power systems.41
9 Earthing of wind turbines and wind farms .43
9.1 General .43
9.1.1 Basic requirements.43
9.1.2 Earth electrode arrangements.43
9.1.3 Earthing system impedance.44
9.2 Equipotential bonding.44
9.2.1 General .44
9.2.2 Lightning equipotential bonding for metal installations .44
9.2.3 Electrically insulated LPS .45
9.3 Structural components.45
9.3.1 General .45
9.3.2 Metal tubular type tower .45
9.3.3 Metal reinforced concrete towers .45
9.3.4 Lattice tower.46
9.3.5 Systems inside the tower.46
9.3.6 Concrete foundation .46
9.3.7 Rocky area foundation.47
9.3.8 Metal mono-pile foundation.47
9.3.9 Offshore foundation .47
9.4 Electrode shape dimensions.47
9.5 Wind farms.48
9.6 Execution and maintenance of the earthing system .48
10 Personal safety .49
11 Documentation of lightning protection system.50
11.1 General .50
11.2 Documentation necessary during assessment for design evaluation .50
11.2.1 General documentation.50
11.2.2 Documentation for rotor blades.51
11.2.3 Documentation of mechanical systems .51
11.2.4 Documentation of electrical and electronic systems .51
11.2.5 Documentation of earthing and bonding systems .51
11.2.6 Documentation of nacelle cover, hub and tower lightning protection
systems.51
11.3 Site specific information .52
11.4 Documentation to be provided for LPS inspections .52
11.4.1 Visual LPS inspection report.52
11.4.2 Complete LPS inspection report .52
11.5 Manuals .52
12 Inspection of lightning protection system .52
12.1 Scope of inspection .52
12.2 Order of inspections .53
12.2.1 General .53
12.2.2 Inspection during production of the wind turbine .53
12.2.3 Inspection during installation of the wind turbine.53

– 4 – 61400-24 © IEC:2010(E)
12.2.4 Inspection during commissioning of the wind turbine and periodic
inspection.53
12.2.5 Inspection after dismantling or repair of main parts.54
12.3 Maintenance.54
Annex A (informative) The lightning phenomenon in relation to wind turbines .55
Annex B (informative) Lightning exposure assessment .66
Annex C (informative) Protection methods for blades.84
Annex D (informative) Test specifications .96
Annex E (informative) Application of lightning protection zones (LPZ) concept at a
wind turbine .119
Annex F (informative) Selection and installation of a coordinated SPD protection in
wind turbines .124
Annex G (informative) Additional information on bonding and shielding and installation
technique.128
Annex H (informative) Testing methods for system level immunity tests. 133
Annex I (informative) Earth termination system . 135
Annex J (informative) Example of defined measuring points. 143
Annex K (informative) Typical lightning damage questionnaire. 145
Annex L (informative) Monitoring systems.148
Annex M (informative) Guidelines for small wind turbines – Microgeneration. 149
Bibliography.150

Figure 1 – Collection area of the wind turbine .24
Figure 2 – Effective height, H, of wind turbine exposed on a hill.24
Figure 3 – Collection area of wind turbine of height H and another structure of height
a
H connected by underground cable of length L .26
b c
Figure 4a – Squirel cage induction generator (SCIG) .42
Figure 4b – Wound rotor induction generator (WRIG).42
Figure 4 – Examples of placement of HV arresters in two typical main electrical circuits
of wind turbines .42
Figure A.1 – Processes involved in the formation of a cloud-to-ground flash .57
Figure A.2 – Typical profile of a negative cloud-to-ground flash (not to scale).58
Figure A.3 – Definitions of short stroke parameters (typically T < 2 ms).58
Figure A.4 – Definitions of long stroke parameters (typically 2 ms < T < 1 s)
long
(Figure A.2 in IEC 62305-1) .59
Figure A.5 – Possible components of downward flashes (typical in flat territory and to
lower structures) (Figure A.3 in IEC 62305-1) .60
Figure A.6 – Typical profile of a positive cloud-to-ground flash .60
Figure A.7 – Typical profile of a negative upward initiated flash .61
Figure A.8 – Possible components of upward flashes (typical to exposed and/or higher
structures) (Figure A.4 in IEC 62305-1).63
Figure C.1 – Types of wind turbine blades .85
Figure C.2 – Lightning protection concepts for large modern wind turbine blades .87
Figure C.3 – Lightning induced voltages between lightning conductor or structure and
sensor wiring .90
Figure D.1 – Initial leader attachment test setup A (specimen should be tested in
several positions representing different directions of the approaching leader).99

61400-24 © IEC:2010(E) – 5 –
Figure D.2 – Possible orientations for the initial leader attachment test setup A.100
Figure D.3 – Leader connection point must be away from test specimen. 101
Figure D.4 – Initial leader attachment test setup B. 102
Figure D.5 – Arrangement for local protection device (e.g. diverter) – Evaluations test
setup C.103
Figure D.6 – Typical switching impulse voltage rise to flashover (100 μs per division) . 104
Figure D.7 – Swept channel test arrangement.108
Figure D.8 – Lightning impulse voltage waveform (Figure 6 in IEC 60060-1) . 108
Figure D.9 – Lightning impulse voltage waveform showing flashover on the wave front
(Figure 7 in IEC 60060-1) .109
Figure D.10 – Typical jet diverting test electrodes.112
Figure D.11 – High-current test arrangement for non-conductive surfaces . 114
Figure D.12 – Example of an arrangement for conducted current tests . 117
Figure E.1 – Rolling sphere model .120
Figure E.2 – Mesh with large mesh dimension for nacelle with GFRP cover. 121
Figure E.3 – Mesh with small mesh dimension for nacelle with GFRP cover. 121
Figure E.4 – Two cabinets both defined as LPZ 2 connected via the shield of a
shielded cable.122
Figure E.5 – Example: Division of wind turbine into different lightning protection zones .123
Figure E.6 – Example of how to document LPMS division of electrical system into
protection zones with indication of where circuits cross LPZ boundaries and showing
the long cables running between tower base and nacelle.123
Figure F.1 – Point-to-point installation scheme (Figure 53E in IEC 60364-5-53). 125
Figure F.2 – Earthing connection installation scheme (Figure A.1 in IEC 60364-5-53).125
Figure G.1 – Two control cabinets located on different metallic planes inside a nacelle .128
Figure G.2 – Magnetic coupling mechanism.129
Figure G.3 – Measuring of transfer impedance. 131
Figure H.1 – Example circuit of a SPD discharge current test under service conditions. 134
Figure H.2 – Example circuit of an induction test due to lightning currents . 134
Figure I.1 – Minimum length (l ) of each earth electrode according to the class of LPS
(Figure 2 in IEC 62305-3) .138
Figure I.2 – Frequency dependence on the impedance to earth (adapted from Cigré
WG C.4.4.02 July 2005 [49]) .
Figure J.1 – Example of measuring points.143
Figure K.1 – Blade outlines for marking locations of damage . 147

Table 1 – Maximum values of lightning parameters according to LPL (Table 5 in
IEC 62305-1) .21
Table 2 – Minimum values of lightning parameters and related rolling sphere radius
corresponding to LPL (Table 6 in IEC 62305-1).22
Table 3 – Collection areas A and A of service line depending on whether aerial or
I i
buried (corresponds to Table A.3 in IEC 62305-2).26
Table 4 – Parameters relevant to the assessment of risk components for wind turbine
(corresponds to Table 8 in IEC 62305-2).28

– 6 – 61400-24 © IEC:2010(E)
Table 5 – Minimum dimensions of conductors connecting different bonding bars/points
or connecting bonding bars/points to the earth termination system (Table 8 in
IEC 62305-3) .45
Table 6 – Minimum dimensions of conductors connecting internal metal installations to
the bonding bar/point (Table 9 in IEC 62305-3).45
Table 7 – LPS General inspection intervals.54
Table A.1 – Cloud-to-ground lightning current parameters (adapted from Table A.1 in
IEC 62305-1) .59
Table A.2 – Upward initiated lightning current parameters .62
Table A.3 – Summary of the lightning threat parameters to be considered in the
calculation of the test values for the different LPS components and for the different
LPL (Table D.1 in IEC 62305-1) .64
Table B.1 – Sources of damage, types of damage and types of loss according to point
of strike (corresponds to Table 1 in IEC 62305-2) .67
Table B.2 – Risk in a wind turbine for each type of damage and of loss  (corresponds
to Table 2 in IEC 62305-2).68
Table B.3 – Values of probability, P , that a lightning flash to a wind turbine will cause
A
shock to living beings due to dangerous touch and step voltages (corresponds to
Table B.1 in IEC 62305-2).71
Table B.4 – Values of probability, P , depending on the protection measures to reduce
B
physical damage (corresponds to Table B.2 in IEC 62305-2) .71
Table B.5 – Values of probability P as a function of the LPL for which the SPDs
SPD
are designed (Table B.3 in IEC 62305-2) .72
Table B.6 – Values of probability, P , depending on the resistance, R , of the cable
LD S
screen and the impulse withstand voltage, U , of the equipment (Table B.6 in
W
IEC 62305-2) .73
Table B.7 – Values of probability, P , depending on the resistance, R , of the cable
LI S
screen and the impulse withstand voltage, U , of the equipment (Table B.7 in
W
IEC 62305-2) .74
Table B.8 – Values of reduction factors r and r as a function of the type of surface of
a u
soil or floor (corresponds to Table C.2 in IEC 62305-2).76
Table B.9 – Values of reduction factor r as a function of provisions taken to reduce
p
the consequences of fire (Table C.3 in IEC 62305-2) .76
Table B.10 – Values of reduction factor r as a function of risk of fire of the wind
f
turbine (corresponds to Table C.4 in IEC 62305-2) .76
Table B.11 – Values of factor h increasing the relative amount of loss in presence of
Z
a special hazard (corresponds to Table C.5 in IEC 62305-2).77
Table B.12 – Typical mean values of L , L and L (corresponds to Table C.7 in
t f o
IEC 62305-2) .77
Table B.13 – Values of factor K as a function of the characteristics of the shielded
d
service line (corresponds to Table D.1 in IEC 62305-2).79
Table B.14 – Values of factor K as a function of the protection measures (Table D.2
p
in IEC 62305-2) .79
Table B.15 – Impulse withstand voltage U as a function of the type of cable (Table
W
D.3 in IEC 62305-2) .79
Table B.16 – Impulse withstand voltage U as a function of the type of apparatus
W
(Table D.4 in IEC 62305-2) .79
Table B.17 – Values of probability P’ , P’ , P’ and P’ as function of the failure
B C V W
current I (Table D.5 in IEC 62305-2) .80
a
Table C.1 – Material, configuration and minimum nominal cross-sectional area of air-
termination conductors, air-termination rods and down conductors (corresponds to
)
Table 6 in IEC 62305-3, future edition 2 ).92

61400-24 © IEC:2010(E) – 7 –
Table C.2 – Physical characteristics of typical materials used in lightning protection
systems (Table D.2 in IEC 62350-1) .93
Table C.3 – Temperature rise [K] for different conductors as a function of W/R (Table
D.3 in IEC 62305-1) .94
Table E.1 – Definition of lightning protection zones according to IEC 62305-1 . 119
Table F.1 – Discharge and impulse current levels for TN systems given in IEC 60364-
5-53.127
Table F.2 – Example of increased discharge and impulse current levels for TN
systems .127
Table I.1 – Impulse efficiency of several ground rod arrangements relative to a 12 m
vertical ground rod (100 %) (adapted from Cigré WG C.4.4.02 July 2005).140
Table I.2 – Symbols used in Tables I.3 to I.6 .140
Table I.3 – Formulae for different earthing electrode configurations . 141
Table I.4 – Formulae for buried ring electrode combined with vertical rods . 142
Table I.5 – Formulae for buried ring electrode combined with radial electrodes. 142
Table I.6 – Formulae for buried straight horizontal electrode combined with vertical
rods .142
Table J.1 – Measuring points and resistances to be recorded . 144

– 8 – 61400-24 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND TURBINES –
Part 24: Lightning protection
FOREWORD
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61400-24 has been prepared by IEC technical committee 88: Wind
turbines.
This first edition replaces IEC/TR 61400-24, published in 2002. It constitutes a technical
revision. It is restructured with a main normative part, while informative information is placed
in annexes.
The text of this standard is based on the following documents:
FDIS Report on voting
88/366/FDIS 88/369/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

61400-24 © IEC:2010(E) – 9 –
A list of all parts of the IEC 61400 series, under the general title: Wind turbines, can be found
on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 10 – 61400-24 © IEC:2010(E)
WIND TURBINES –
Part 24: Lightning protection
1 Scope
This International Standard applies to lightning protection of wind turbine generators and wind
power systems.
Normative references are made to generic standards for lightning protection, low-voltage
systems and high-voltage systems for machinery and installations and electromagnetic
compatibility (EMC).
This standard defines the lightning environment for wind turbines and application of the
environment for risk assessment for the wind turbine. It defines requirements for protection of
blades, other structural components and electrical and control systems against both direct
and indirect effects of lightning. Test methods to validate compliance are recommended.
Guidance on the use of applicable lightning protection, industrial electrical and EMC
standards including earthing is provided.
Guidance regarding personal safety is provided.
Guidelines for damage statistics and reporting are provided.
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.
IEC 60060-1:1989, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60068 (all parts), Environmental testing
IEC 60071 (all parts), Insulation Co-ordination
IEC 60071-2:1996, Insulation Co-ordination – Part 2: Application guide
IEC 60099-4, Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c.
systems
IEC 60099-5, Surg
...