Exposure to electric or magnetic fields in the low and intermediate frequency range - Methods for calculating the current density and internal electric field induced in the human body -- Part 3-1: Exposure to electric fields - Analytical and 2D numerical models

This part of IEC 62226 applies to the frequency range for which exposure limits are based on the induction of voltages or currents in the human body when exposed to electric fields. This part defines in detail the coupling factor K - introduced by the IEC 62226 series to enable exposure assessment for complex exposure situations, such as non-uniform magnetic field or perturbed electric field - for the case of simple models of the human body, exposed to uniform electric fields. The coupling factor K has different physical interpretations depending on whether it relates to electric or magnetic field exposure. It is the so called "shape factor for electric field". This part of IEC 62226 can be used when the electric field can be considered to be uniform, for frequencies up to at least 100 kHz. This situation of exposure to a "uniform" electric field is mostly found in the vicinity of high voltage overhead power systems. For this reason, illustrations given in this part are given for power frequencies (50 Hz and 60 Hz).

Sicherheit in elektrischen oder magnetischen Feldern im niedrigen und mittleren Frequenzbereich - Verfahren zur Berechnung der induzierten Körperstromdichte und des im menschlichen Körpers induzierten elektrischen Feldes -- Teil 3-1: Exposition gegenüber elektrischen Feldern - Analytische Modelle und numerische 2D-Modelle

Exposition aux champs électriques ou magnétiques à basse et moyenne fréquence - Méthodes de calcul des densités de courant induit et des champs électriques induits dans le corps humain -- Partie 3-1: Exposition à des champs électriques - Modèles analytiques et numériques 2D

S'applique à la gamme de fréquences pour laquelle les limites d'exposition sont fondées sur des tensions ou des courants induits dans le corps humain, quand il est exposé aux champs électriques. Définit le facteur de forme K - introduit par la série CEI 62226 pour permettre l'évaluation de l'exposition dans des situations d'expositions complexes, telles qu'un champ magnétique non uniforme ou un champ électrique perturbé - pour les cas de modèles simples de corps humain, exposé à des champs électriques uniformes. Le facteur de couplage K peut avoir différentes interprétations physiques selon qu'il se réfère à l'exposition à un champ électrique ou magnétique. Il est aussi appelé 'facteur de couplage pour champ électrique'. La présente partie de la CEI 62226 peut être utilisée quand le champ électrique peut être considéré comme uniforme, pour des fréquences jusqu'à au moins 100 kHz. Cette situation d'exposition à un champ électrique 'uniforme' se trouve principalement à proximité des systèmes aériens d'alimentation électrique à haute tension. Pour cette raison, les illustrations données dans cette section sont aux fréquences industrielles (50 Hz et 60 Hz).

Izpostavljenost električnim in magnetnim poljem v nizkem in srednjem frekvenčnem obsegu - Metode za izračunavanje trenutne gostote in notranjega induciranega električnega polja v človeškem telesu - 3-1. del: Izpostavljenost magnetnim poljem - Analitični in numerični 2D modeli (IEC 62226-3-1:2007)

Ta del standarda IEC 62226 se uporablja za frekvenčni obseg, za katerega mejne vrednosti izpostavljenosti temeljijo na indukciji napetosti ali tokov v človeškem telesu, izpostavljenem električnim poljem. Ta del podrobno določa faktor sklopa K, predstavljen v skupini standardov IEC 62226 za oceno izpostavljenosti v zapletenih primerih izpostavljenosti (na primer pri neenakomernem magnetnem polju ali motenem električnem polju), za primer preprostih modelov človeškega telesa, izpostavljenega enakomernemu električnemu polju. Faktor sklopa K vključuje različne fizikalne razlage glede na to, ali gre za električno ali magnetno polje izpostavljenosti. Gre za tako imenovani »oblikovni faktor za električno polje«. Ta del standarda IEC 62226 se lahko uporablja, kadar se lahko električno polje obravnava kot enakomerno, za frekvence do vsaj 100 kHz. Do te izpostavljenosti »enakomernemu« električnemu polju običajno pride v bližini nadzemnih visokonapetostnih omrežnih sistemov. Zaradi tega so slike v tem delu standarda podane za omrežne frekvence (50 Hz in 60 Hz).

General Information

Status
Published
Publication Date
22-Nov-2007
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
04-Oct-2007
Due Date
09-Dec-2007
Completion Date
23-Nov-2007

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SLOVENSKI STANDARD
SIST EN 62226-3-1:2008
01-januar-2008
,]SRVWDYOMHQRVWHOHNWULþQLPLQPDJQHWQLPSROMHPYQL]NHPLQVUHGQMHP
IUHNYHQþQHPREVHJX0HWRGH]DL]UDþXQDYDQMHWUHQXWQHJRVWRWHLQQRWUDQMHJD
LQGXFLUDQHJDHOHNWULþQHJDSROMDYþORYHãNHPWHOHVXGHO,]SRVWDYOMHQRVW
PDJQHWQLPSROMHP$QDOLWLþQLLQQXPHULþQL'PRGHOL ,(&

Exposure to electric or magnetic fields in the low and intermediate frequency range -

Methods for calculating the current density and internal electric field induced in the

human body - Part 3-1: Exposure to electric fields - Analytical and 2D numerical models

Sicherheit in elektrischen oder magnetischen Feldern im niedrigen und mittleren

Frequenzbereich - Verfahren zur Berechnung der induzierten Körperstromdichte und des

im menschlichen Körpers induzierten elektrischen Feldes - Teil 3-1: Exposition
gegenüber elektrischen Feldern - Analytische Modelle und numerische 2D-Modelle
Exposition aux champs électriques ou magnétiques a basse et moyenne fréquence -

Méthodes de calcul des densités de courant induit et des champs électriques induits

dans le corps humain - Partie 3-1: Exposition a des champs électriques - Modeles
analytiques et numériques 2D
Ta slovenski standard je istoveten z: EN 62226-3-1:2007
ICS:
17.220.20 0HUMHQMHHOHNWULþQLKLQ Measurement of electrical
PDJQHWQLKYHOLþLQ and magnetic quantities
SIST EN 62226-3-1:2008 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
EUROPEAN STANDARD
EN 62226-3-1
NORME EUROPÉENNE
September 2007
EUROPÄISCHE NORM
ICS 17.220.20
English version
Exposure to electric or magnetic fields
in the low and intermediate frequency range -
Methods for calculating the current density
and internal electric field induced in the human body -
Part 3-1: Exposure to electric fields -
Analytical and 2D numerical models
(IEC 62226-3-1:2007)
Exposition aux champs électriques Sicherheit in elektrischen
ou magnétiques à basse oder magnetischen Feldern im niedrigen
et moyenne fréquence - und mittleren Frequenzbereich -
Méthodes de calcul des densités Verfahren zur Berechnung der induzierten

de courant induit et des champs électriques Körperstromdichte und des im menschlichen

induits dans le corps humain - Körpers induzierten elektrischen Feldes -
Partie 3-1: Exposition Teil 3-1: Exposition gegenüber
à des champs électriques - elektrischen Feldern -
Modèles analytiques et numériques 2D Analytische Modelle
(CEI 62226-3-1:2007) und numerische 2D-Modelle
(IEC 62226-3-1:2007)

This European Standard was approved by CENELEC on 2007-09-01. 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, Cyprus, the

Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,

Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 62226-3-1:2007 E
---------------------- Page: 2 ----------------------
EN 62226-3-1:2007 - 2 -
Foreword

The text of document 106/125/FDIS, future edition 1 of IEC 62226-3-1, prepared by IEC TC 106, Methods

for the assessment of electric, magnetic and electromagnetic fields associated with human exposure, was

submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 62226-3-1 on

2007-09-01.
This European Standard is to be used in conjunction with EN 62226-1:2005.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2008-06-01
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2010-09-01
with the EN have to be withdrawn
__________
Endorsement notice

The text of the International Standard IEC 62226-3-1:2007 was approved by CENELEC as a European

Standard without any modification.
__________
---------------------- Page: 3 ----------------------
INTERNATIONAL IEC
STANDARD
CEI
62226-3-1
NORME
First edition
INTERNATIONALE
Première édition
2007-05
Exposure to electric or magnetic fields
in the low and intermediate frequency range –
Methods for calculating the current density and
internal electric field induced in the human body –
Part 3-1:
Exposure to electric fields –
Analytical and 2D numerical models
Exposition aux champs électriques ou
magnétiques à basse et moyenne fréquence –
Méthodes de calcul des densités de courant
induit et des champs électriques induits dans
le corps humain –
Partie 3-1:
Exposition à des champs électriques –
Modèles analytiques et numériques 2D
PRICE CODE
CODE PRIX
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
Pour prix, voir catalogue en vigueur
---------------------- Page: 4 ----------------------
– 2 – 62226-3-1 © IEC:2007
CONTENTS

FOREWORD...........................................................................................................................5

INTRODUCTION.....................................................................................................................7

1 Scope...............................................................................................................................8

2 Exposure to electric field ..................................................................................................8

3 General procedure..........................................................................................................11

3.1 Shape factor..........................................................................................................11

3.2 Procedure .............................................................................................................11

4 Human body models .......................................................................................................12

4.1 General .................................................................................................................12

4.2 Surface area .........................................................................................................12

4.3 Semi-spheroidal model..........................................................................................13

4.4 Axisymmetrical body model ...................................................................................15

5 Calculation of induced current ........................................................................................16

5.1 General .................................................................................................................16

5.2 Semi-spheroid .......................................................................................................16

5.3 Axisymmetrical models ..........................................................................................20

5.4 Comparison of the analytical and numerical models ..............................................27

6 Influence of electrical parameters ...................................................................................27

6.1 General .................................................................................................................27

6.2 Influence of permittivity .........................................................................................27

6.3 Influence of conductivity........................................................................................28

6.4 Non-homogeneous conductivity.............................................................................28

7 Measurement of currents induced by electric fields.........................................................28

7.1 General .................................................................................................................28

7.2 Current flowing to the ground ................................................................................28

Annex A (normative) Analytical solutions for a spheroid in a uniform electric field................30

Annex B (normative) Human body axisymmetrical model .....................................................33

Annex C (informative) Child body model ..............................................................................38

Annex D (informative) Example of use of this standard ........................................................40

Annex E (informative) Numerical calculation methods ..........................................................44

Bibliography..........................................................................................................................52

Figure 1 – Illustration of the phenomenon of currents induced by electric field in a

human body standing on the ground .....................................................................................10

Figure 2 – Potential lines of the electric field generated by an energised wire in the

absence of any objects (all distances in metres) ...................................................................10

Figure 3 – A realistic body model ..........................................................................................12

Figure 4 – Scheme of the semi-spheroid simulating a human being standing on a zero

potential plane ......................................................................................................................13

Figure 5 – Equivalent spheroid radius, R, versus height, L, and for different mass, M ..........15

Figure 6 – The axisymmetrical body model for the reference man (left) and woman

(right)....................................................................................................................................15

---------------------- Page: 5 ----------------------
62226-3-1 © IEC:2007 – 3 –

Figure 7 – Conductive spheroid exposed to electric field.......................................................16

Figure 8 – Calculation of the shape factor for electric field K for an spheroid exposed

to an unperturbed electric field..............................................................................................17

Figure 9 – Current density J induced by an unperturbed electric field (1 kV/m, 50 Hz)

in a spheroid versus parameter L/R (values in µA/m²)...........................................................18

Figure 10 – Dimensions and mesh of the semi-spheroid .......................................................19

Figure 11 – Distortion of power frequency electric field lines close to the conductive

semi-spheroid .......................................................................................................................19

Figure 12 – Calculated induced current density J (h) in the body standing in a vertical

50 Hz electric field of 1 kV/m ................................................................................................21

Figure 13 – Computation domain ..........................................................................................23

Figure 14 – Mesh of the man body model and distortion of power frequency electric

field lines close to model.......................................................................................................23

Figure 15 – Distribution of potential lines and 50 Hz electric field magnitude (man

model) ..................................................................................................................................24

Figure 16 – Computation of induced currents J along a vertical axis, and distribution

of induced currents in the man model at 50 Hz .....................................................................24

Figure 17 – Mesh of the woman body model and distortion of power frequency electric

field lines close to model.......................................................................................................25

Figure 18 – Distribution of potential lines and 50 Hz electric field magnitude (woman

model) ..................................................................................................................................26

Figure 19 – Computation of induced currents J along a vertical axis, and distribution

of induced currents in the woman model at 50 Hz .................................................................26

Figure A.1 – Conductive spheroid exposed to electric field ...................................................30

Figure B.1 – Normalised axisymmetrical models. Left: man, Right: woman ...........................35

Figure C.1 – Computation of induced currents J along a vertical axis, and distribution

of induced currents in the 10 years reference child model.....................................................39

Figure E.1 – Spheroid model.................................................................................................45

Figure E.2 – Space potential model ......................................................................................46

Figure E.3 – Exemple of charge simulation method using rings.............................................47

Figure E.4 – Superficial charges integral equation method, cutting of the body into N

elements...............................................................................................................................48

Figure E.5 – Mesh of the body using finite element method ..................................................49

Figure E.6 – Impedance method ...........................................................................................50

Figure E.7 – Yee-method: Electric and magnetic grids for spatial discretization ....................51

Table 1 – Data for reference man and reference woman .......................................................13

Table 2 – Values of arcsin(e) / e for different values of L/R...................................................14

Table 3 – Derived data using spheroid model at 50 Hz .........................................................20

Table 4 – Electric field E required to produce basic restrictions J in the neck at

BR BR

50 Hz....................................................................................................................................22

Table 5 – Comparison of values of the shape factor for electric field K and

corresponding current densities for an unperturbed 50 Hz electric field of 1 kV/m .................27

Table B.1 – Measures from antropomorphic survey used to construct vertical

dimensions of axisymmetrical model [56] ..............................................................................34

---------------------- Page: 6 ----------------------
– 4 – 62226-3-1 © IEC:2007
Table B.2 – Measures from antropomorphic survey used to construct the radial

dimensions of axisymmetrical model [56] ..............................................................................34

Table B.3 – Normalised model dimensions............................................................................36

Table B.4 – Axisymmetric model dimensions for reference man and reference woman

whose mass and height are defined by ICRP [38] and are given in Table 1...........................37

Table C.1 – Reference values provided by ICRP for male and female children......................38

Table C.2 – Dimensions of the reference children (in m excepted SB in m²) .......................38

Table C.3 – Results of analytical method for the reference children ......................................39

Table D.1 – Normalised dimensions of the women model......................................................41

Table D.2 – Calculation of the dimensions for a specific person............................................42

---------------------- Page: 7 ----------------------
62226-3-1 © IEC:2007 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPOSURE TO ELECTRIC OR MAGNETIC FIELDS
IN THE LOW AND INTERMEDIATE FREQUENCY RANGE –
METHODS FOR CALCULATING THE CURRENT DENSITY AND
INTERNAL ELECTRIC FIELD INDUCED IN THE HUMAN BODY –
Part 3-1: Exposure to electric fields –
Analytical and 2D numerical models
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with an IEC Publication.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) 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 62226-3-1 has been prepared by IEC technical committee 106:

Methods for the assessment of electric, magnetic and electromagnetic fields associated with

human exposure.

This standard is to be used in conjunction with the first edition of IEC 62226-1:2004, Exposure

to electric or magnetic fields in the low and intermediate frequency range – Methods for

calculating the current density and internal electric field induced in the human body – Part 1:

General.
---------------------- Page: 8 ----------------------
– 6 – 62226-3-1 © IEC:2007
The text of this standard is based on the following documents:
FDIS Report on voting
106/125/FDIS 106/128/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.

This International Standard constitutes Part 3-1 of IEC 62226 series, which will regroup

several international standards and technical reports within the framework of the calculation

of induced current densities and internal electric fields.

A list of all parts of the IEC 62226 series, published under the general title Exposure to electric or

magnetic fields in the low and intermediate frequency range – Methods for calculating the

current density and internal electric field induced in the human body, can be found on the IEC

website.

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.
---------------------- Page: 9 ----------------------
62226-3-1 © IEC:2007 – 7 –
INTRODUCTION

Public interest concerning human exposure to electric and magnetic fields has led

international and national organisations to propose limits based on recognised adverse

effects.

This standard applies to the frequency range for which the exposure limits are based on the

induction of voltages or currents in the human body, when exposed to electric and magnetic

fields. This frequency range covers the low and intermediate frequencies, up to 100 kHz.

Some methods described in this standard can be used at higher frequencies under specific

conditions.
The exposure limits based on biological and medical experimentation about these

fundamental induction phenomena are usually called “basic restrictions”. They include safety

factors.

The induced electrical quantities are not directly measurable, so simplified derived limits are

also proposed. These limits, called “reference levels” are given in terms of external electric

and magnetic fields. They are based on very simple models of coupling between external

fields and the body. These derived limits are conservative.

Sophisticated models for calculating induced currents in the body have been used and are the

subject of a number of scientific publications. These models use numerical 3D

electromagnetic field computation codes and detailed models of the internal structure with

specific electrical characteristics of each tissue within the body. However such models are still

developing; the electrical conductivity data available at present has considerable

shortcomings; and the spatial resolution of models is still progressing. Such models are

therefore still considered to be in the field of scientific research and at present it is not

considered that the results obtained from such models should be fixed indefinitely within

standards. However it is recognised that such models can and do make a useful contribution

to the standardisation process, specially for product standards where particular cases of

exposure are considered. When results from such models are used in standards, the results

should be reviewed from time to time to ensure they continue to reflect the current status of

the science.
---------------------- Page: 10 ----------------------
– 8 – 62226-3-1 © IEC:2007
EXPOSURE TO ELECTRIC OR MAGNETIC FIELDS
IN THE LOW AND INTERMEDIATE FREQUENCY RANGE –
METHODS FOR CALCULATING THE CURRENT DENSITY AND
INTERNAL ELECTRIC FIELD INDUCED IN THE HUMAN BODY –
Part 3-1: Exposure to electric fields –
Analytical and 2D numerical models
1 Scope

This part of IEC 62226 applies to the frequency range for which exposure limits are based on

the induction of voltages or currents in the human body when exposed to electric fields.

This part defines in detail the coupling factor K – introduced by the IEC 62226 series to

enable exposure assessment for complex exposure situations, such as non-uniform magnetic

field or perturbed electric field – for the case of simple models of the human body, exposed to

uniform electric fields. The coupling factor K has different physical interpretations depending

on whether it relates to electric or magnetic field exposure. It is the so called “shape factor for

electric field”.

This part of IEC 62226 can be used when the electric field can be considered to be uniform,

for frequencies up to at least 100 kHz.

This situation of exposure to a “uniform” electric field is mostly found in the vicinity of high

voltage overhead power systems. For this reason, illustrations given in this part are given for

power frequencies (50 Hz and 60 Hz).
2 Exposure to electric field

Alternating electric fields are generated by energised conductors (i.e. under voltage). In the

immediate vicinity of domestic electrical equipment, such as lights, switches, food mixers and

irons, local electric-field strengths about 100 V/m may be found. Such fields are non-uniform,

but their strengths are far below the levels recommended in safety guidelines, so there is no

need of calculation of induced currents in such exposure situations.

Higher electric-field strengths may be found in the vicinity of high voltage equipment such as

electric power line. In the frequency range covered by this standard, it is considered that

exposure from power lines is the only significant exposure source for public regarding safety

guidelines limits.

Guidelines on human exposure to electric fields are generally expressed in terms of induced

current density or internal electric field. These quantities cannot be measured directly and the

purpose of this document is to give guidance on how to assess these quantities induced in the

human body by external (environmental) electric fields E .
---------------------- Page: 11 ----------------------
62226-3-1 © IEC:2007 – 9 –

The induced current density J and the internal electric field E are closely linked by the simple

relation:
J =σ.E (1)
where σ is the conductivity of the body tissue under consideration.

For reason of simplification, the content of this standard is presented in terms of induced

current densities J, from which values of internal electric field E can be easily derived using

the previous formula.

All the calculation developed in this document use the low frequency approximation in which

displacement currents are negligible, such that εω/σ is less than 1 in the body. This

approximation has been checked using published tissue data [29,31] in the low frequency

range and it has been found to be valid for frequencies up to at least 100 kHz and is probably

valid at higher frequencies.
Computations based on sophisticated numerical models of the human body [24] also

demonstrate that this assumption is valid at frequencies up to more than 100 kHz by showing

that the relationship between the induced current density in the body and the product of

frequency and external electric field hardly varies at all between 50 Hz and 1 MHz, and is only

slightly altered at 10 MHz.
Analytical models can be used for simple cases of calculations.

Electric fields cause displacement of electric charges in conductive objects (including living

bodies) and, because these fields are alternating, the electric charges move backwards and

forwards. The result is an “induced” alternating current inside the conductive object. This

current depends only on:
– the shape and size of the conducting object;

– the characteristics (magnitude, polarisation, degree of non-uniformity, etc.) of the

unperturbed field (field which is measured in the absence of any conducting object);

– the frequency of the field

– the variation of conductivity of the object (in homogeneous media, the current density

induced by electric fields does not depend on conductivity).

Figure 1 illustrates this induction phenomenon for the case where the body is in electrical

contact with the ground.
—————————
Figures in square brackets refer to the Bibliography.
---------------------- Page: 12 ----------------------
– 10 – 62226-3-1 © IEC:2007
Electric fields
Induced currents
IEC 750/07

Figure 1 – Illustration of the phenomenon of currents induced by an electric field in a

human body standing on the ground

The typical case of public exposure to an electric field is under high voltage power

transmission lines. In this case, the distance be
...

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