SIST EN 62305-1:2011

SLOVENSKI STANDARD
oSIST FprEN 62305-1:2009
01-december-2009
=DãþLWDSUHGGHORYDQMHPVWUHOHGHO6SORãQDQDþHOD
Protection against lightning -- Part 1: General principles
Protection contre la foudre -- Partie 1: Principes généraux
Ta slovenski standard je istoveten z: FprEN 62305-1:2009
ICS:
29.020 Elektrotehnika na splošno Electrical engineering in
general
91.120.40 =DãþLWDSUHGVWUHOR Lightning protection
oSIST FprEN 62305-1:2009 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST FprEN 62305-1:2009

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oSIST FprEN 62305-1:2009

81/335/CDV
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Project number IEC 62305-1 Ed.2
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Also of interest to the following committees Supersedes document
Intéresse également les comités suivants Remplace le document
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Titre : Protection contre la foudre - Partie 1: Title : Protection against lightning - Part 1:
Principes généraux General Principles



Note d'introduction Introductory note
This CDV is circulated in English only in the absence
of a French version from the French national
committee within two months from date of request.


ATTENTION ATTENTION
VOTE PARALLÈLE IEC – CENELEC
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vote parallèle. parallel voting.
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Copyright © 2009 International Electrotechnical Commission, IEC. All rights reserved. It is
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® Registered trademark of the International Electrotechnical Commission
2009-01-09

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oSIST FprEN 62305-1:2009
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CONTENTS
FOREWORD .5
INTRODUCTION .7

1 Scope .8
2 Normative references .8
3 Terms and definitions .8
4 Lightning current parameters .14
5 Damage due to lightning.14
5.1 Damage to a structure .14
5.2 Types of loss.17
6 Need and economic convenience for lightning protection .18
6.1 Need for lightning protection.18
6.2 Economic convenience of lightning protection .19
7 Protection measures.19
7.1 Protection measures to reduce injury of living beings due to touch and step
voltages .19
7.2 Protection measures to reduce physical damage.19
7.3 Protection measures to reduce failure of electrical and electronic systems .20
7.4 Protection measures selection .20
8 Basic criteria for protection of structures.20
8.1 Lightning protection levels (LPL).21
8.2 Lightning protection zones (LPZ) .23
8.3 Protection of structures .26

Annex A (informative) Parameters of lightning current .28
Annex B (informative) Time functions of the lightning current for analysis purposes .
Annex C (informative) Simulation of the lightning current for test purposes .46
Annex D (informative) Test parameters simulating the effects of lightning on LPS
components.50
Annex E (informative) Surges due to lightning at different installation points.

Bibliography .71

Figure 1 The connection between the parts of this standard

Figure 2 – Types of loss and corresponding risks resulting from different types of
damage .18
Figure 3 – LPZ defined by an LPS (IEC 62305-3) .
Figure 4 – LPZ defined by protection measures against LEMP (IEC 62305-4
Figure A.1 – Definitions of impulse parameters (typically T <2 ms) .28
2
Figure A.2 – Definitions of long stroke parameters (typically 2 ms long
Figure A.3 – Possible components of downward flashes (typical in flat territory and to
lower structures).29
Figure A.4 – Possible components of upward flashes (typical to exposed and/or
higher structures) .30

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Figure A.5 – Cumulative frequency distribution of lightning current parameters (lines
through 95 % and 5 % value) .34
Figure B.1 – Shape of the current rise of the positive impulse .40
Figure B.2 – Shape of the current tail of the positive impulse.41
Figure B.3 – Shape of the current rise of the first negative impulse.43
Figure B.4 – Shape of the current tail of the first negative impulse.44
Figure B.5 – Shape of the current rise of the subsequent negative impulses .43
Figure B.6 – Shape of the current tail of the subsequent negative impulses .44
Figure B.7 – Amplitude density of the lightning current according to LPL I .45
Figure C.1 – Example test generator for the simulation of the specific energy of the
first impulse and the charge of the long stroke .47
Figure C.2 – Definition for the current steepness in accordance with Table C.3 .48
Figure C.3 – Example test generator for the simulation of the front steepness of the
first impulse for large test items .49
Figure C.4 – Example test generator for the simulation of the front steepness of the
subsequent impulses for large test items.49
Figure D.1 – General arrangement of two conductors for the calculation of
electrodynamic force .57
Figure D.2 – Typical conductor arrangement in an LPS .57
Figure D.3 – Diagram of the stresses for the configuration of Figure D.2 .58
Figure D.4 – Force per unit length along the horizontal conductor of Figure D.2 .58

Table 1 – Effects of lightning on typical structures.15
Table 2 – Damages and loss in a structure according to different points of strike of
lightning .17
Table 3 – Maximum values of lightning parameters according to LPL.22
Table 4 – Minimum values of lightning parameters and related rolling sphere radius
corresponding to LPL.23
Table 5 – Probabilities for the limits of the lightning current parameters.23
Table A.1 – Tabulated values of lightning current parameters taken from CIGRE
[3], [4]
(Electra No. 41 or No. 69*) .31
Table A.2 – Logarithmic normal distribution of lightning current parameters –
Mean µ and dispersion σ calculated from 95 % and 5 % values from CIGRE
log
[3], [4]
(Electra No. 41 or No. 69) .32
Table A.3 – Values of probability P as function of the lightning current I
Table B.1 – Parameters for Equation B.1 .
Table C.1 – Test parameters of the first impulse .47
Table C.2 – Test parameters of the long stroke .47
Table C.3 – Test parameters of the impulses .48
Table D.1 – 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 51
Table D.2 – Physical characteristics of typical materials used in LPS components.54
Table D.3 – Temperature rise for conductors of different sections as a function of W/R .54
Table E.1 – Conventional earthing impedance values Z and Z according to the
1

resistivity of the soil .66

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Table E.2a – Expected surge overcurrents due to lightning flashes on low voltage
systems…………………………………………………………………………………67
Table E.2b – Expected surge overcurrents due to lightning flashes on telecommunication
systems…………………………………………………………………………………68

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oSIST FprEN 62305-1:2009
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

PROTECTION AGAINST LIGHTNING –

Part 1: General principles


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) 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 62305-1 has been prepared by IEC technical committee 81:
Lightning protection.
The text of this second edition of IEC 62305-1 is compiled from and replaces IEC 62305-1,
first edition (2006).
The text of this standard is based on the following documents:
FDIS Report on voting
81/xxx/FDIS 81/xxx/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, as close as possible, in accordance with the ISO/IEC
Directives, Part 2.

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oSIST FprEN 62305-1:2009
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IEC 62305 consists of the following parts, under the general title Protection against lightning:
Part 1: General principles
Part 2: Risk management
Part 3: Physical damage to structures and life hazard
Part 4: Electrical and electronic systems within structures
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.

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INTRODUCTION
There are no devices nor methods capable of modifying the natural weather phenomena to
the extent that they can prevent lightning discharges. Lightning flashes to, or nearby,
structures (or lines connected to the structures) are hazardous to people, to the structures
themselves, their contents and installations as well as to lines. This is why the application of
lightning protection measures is essential.
The need for protection, the economic benefits of installing protection measures and the
selection of adequate protection measures should be determined in terms of risk
management. Risk management is the subject of IEC 62305-2.
Protection measures considered in this standard are proved to be effective in risk reduction.
All measures for protection against lightning form the overall lightning protection. For
practical reasons the criteria for design, installation and maintenance of lightning protection
measures are considered in two separate groups:
– the first group concerns protection measures to reduce physical damage and life hazard
in a structure is given in IEC 62305-3,
– the second group concerns protection measures to reduce failures of electrical and
electronic systems in a structure is given in IEC 62305-4,
The connection between the parts of this standard is illustrated in Figure 1.
The lightning tThe lightning thhreat reat IECIEC 62305 62305-1-1
Lightning risLightning riskk IIEECC 62305 62305-2-2
LPLP
Lightning protecLightning protection tion
LPSLPS ESP ESP

IEC 62305IEC 62305IEC 62305-3-3-3 IIIEEECCC 62305 62305 62305 - - - 4 4 4
Protec tion measures




Figure 1 The connection between the parts of this standard

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PROTECTION AGAINST LIGHTNING –

Part 1: General principles



1 Scope
This part of IEC 62305 provides the general principles to be followed in the protection against
lightning of structures including their installations and contents as well as persons,
The following cases are outside the scope of this standard:
– railway systems;
– vehicles, ships, aircraft, offshore installations;
– underground high pressure pipelines;
− pipe, power and telecommunication lines not connected to a structure.
NOTE Usually these systems are under special regulations made by various specific authorities.

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 62305-2, Protection against lightning – Part 2: Risk management
IEC 62305-3, Protection against lightning – Part 3: Physical damage to structures and life
hazard
IEC 62305-4, Protection against lightning – Part 4: Electrical and electronic systems within
structures
3 Terms and definitions
For the purposes of this Standard, the following terms and definitions apply.
3.1
lightning flash to earth
electrical discharge of atmospheric origin between cloud and earth consisting of one or more
strokes
3.2
downward flash
lightning flash initiated by a downward leader from cloud to earth
NOTE A downward flash consists of a first impulse, which can be followed by subsequent impulses. One or more
impulses may be followed by a long stroke.

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3.3
upward flash
lightning flash initiated by an upward leader from an earthed structure to cloud
NOTE An upward flash consists of a first long stroke with or without multiple superimposed impulses. One or
more impulses may be followed by a long stroke.
3.4
lightning stroke
single electrical discharge in a lightning flash to earth
3.5
short stroke
part of the lightning flash which corresponds to an impulse current
NOTE This current has a time T to the half peak value on the tail typically less than 2 ms (see Figure A.1).
2
3.6
long stroke
part of the lightning flash which corresponds to a continuing current
NOTE The duration time T (time from the 10 % value on the front to the 10 % value on the tail) of this
long
continuing current is typically more than 2 ms and less than 1 s (see Figure A.2)
3.7
multiple strokes
lightning flash consisting on average of 3-4 strokes, with typical time interval between them of
about 50 ms
NOTE Events having up to a few dozen strokes with intervals between them ranging from 10 ms to 250 ms have
been reported.
3.8
point of strike
point where a lightning flash strikes the earth, or protruding structure (e.g. structure, LPS,
line, tree, etc.)
NOTE A lightning flash may have more than one point of strike.
3.9
lightning current
i
current flowing at the point of strike
3.10
current peak value
I
maximum value of the lightning current
3.11
average steepness of the front of impulse current
average rate of change of current within a time interval ∆t = t – t
2 1
NOTE It is expressed by the difference ∆i= i(t ) – i(t ) of the values of the current at the start and at the end of
2 1
this interval, divided by the time interval ∆t = t – t (see Figure A.1).
2 1

3.12
front time of impulse current
T
1
virtual parameter defined as 1,25 times the time interval between the instants when the 10 %
and 90 % of the peak value are reached (see Figure A.1)

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3.13
virtual origin of impulse current
O
1
point of intersection with time axis of a straight line drawn through the 10 % and the 90 %
reference points on the stroke current front (see Figure A.1); it precedes by 0,1 T that instant
1
at which the current attains 10 % of its peak value
3.14
time to half value of impulse current
T
2
virtual parameter defined as the time interval between the virtual origin O and the instant at
1
which the current has decreased to half the peak value (see Figure A.1)
3.15
flash duration
T
time for which the lightning current flows at the point of strike
3.16
duration of long stroke current
T
long
time duration during which the current in a long stroke is between the 10 % of the peak value
during the increase of the continuing current and 10 % of the peak value during the decrease
of the continuing current (see Figure A.2)
3.17
flash charge
Q
flash
the value resulting from the time integral of the lightning current for the entire lightning flash
duration
3.18
impulse charge
Q
short
the value resulting from the time integral of the lightning current in a impulse
3.19
long stroke charge
Q
long
the value resulting from the time integral of the lightning current in a long stroke
3.20
specific energy
W/R
the value resulting from the time integral of the square of the lightning current for the entire
flash duration
NOTE It represents the energy dissipated by the lightning current in a unit resistance.
3.21
specific energy of impulse current
the value resulting from the time integral of the square of the lightning current for the duration
of the impulse
NOTE The specific energy in a long stroke current is negligible.

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3.22
structure to be protected
structure for which protection is required against the effects of lightning in accordance with
this standard
NOTE A structure to be protected may be a part of a larger structure.
3.23
line
power line or telecommunication line connected to the structure to be protected
3.24
telecommunication lines
lines intended for communication between equipment that may be located in separate
structures, such as phone line and data line
3.25
power lines
distribution lines feeding electrical energy into a structure to power electrical and electronic
equipment located there, such as low voltage (LV) or high voltage (HV) electric mains
3.26
lightning flash to a structure
lightning flash striking a structure to be protected
3.27
lightning flash near a structure
lightning flash striking close enough to a structure to be protected that it may cause
dangerous overvoltages
3.28
electrical system
system incorporating low voltage power supply components
3.29
electronic system
system incorporating sensitive electronic components such as telecommunication equipment,
computer, control and instrumentation systems, radio systems, power electronic installations
3.30
internal systems
electrical and electronic systems within a structure
3.31
physical damage
damage to a structure (or to its contents) or to a line due to mechanical, thermal, chemical
and explosive effects of lightning
3.32
injury of living beings
permanent injuries, including loss of life, to people or to animals by electric shock due to
touch and step voltages caused by lightning
Note: Although living beings may be injured in other ways, in this standard the term injury to living beings is limited
to the threat due to electrical shock (type of damage D1).

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3.33
failure of electrical and electronic systems
permanent damage of electrical and electronic systems due to LEMP
3.34
lightning electromagnetic impulse
LEMP
all electromagnetic effects of lightning current via resistive, inductive and capacitive coupling
which create surges and radiated electromagnetic fields.
3.35
surge
transient created by LEMP which appears as an overvoltage and/or an overcurrent
3.36
lightning protection zone
LPZ
zone where the lightning electromagnetic environment is defined
NOTE The zone boundaries of an LPZ are not necessarily physical boundaries (e.g. walls, floor and ceiling).
3.37
risk
R
value of probable average annual loss (humans and goods) due to lightning, relative to the
total value (humans and goods) of the structure to be protected
3.38
tolerable risk
R
T
maximum value of the risk which can be tolerated for the structure to be protected
3.39
lightning protection level
LPL
number related to a set of lightning current parameters values relevant to the probability that
the associated maximum and minimum design values will not be exceeded in naturally
occurring lightning
NOTE Lightning protection level is used to design protection measures according to the relevant set of lightning
current parameters.
3.40
protection measures
measures to be adopted for the structure to be protected to reduce the risk
3.41a
lightning protection
LP
complete system for the protection of structures and/or electrical and electronic systems in
those structures from the effects of lightning, in general consisting of an LPS and ESP
3.41
lightning protection system
LPS
complete system used to reduce physical damage due to lightning flashes to a structure
NOTE It consists of both external and internal lightning protection systems.

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3.42
external lightning protection system
part of the LPS consisting of an air-termination system, a down-con
...