EN 50443:2011

SLOVENSKI STANDARD
01-februar-2012
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Effects of electromagnetic interference on pipelines caused by high voltage a.c. electric
traction systems and/or high voltage a.c. power supply systems
Auswirkungen elektromagnetischer Beeinflussungen von
Hochspannungswechselstrombahnen und/oder Hochspannungsanlagen auf
Rohrleitungen
Effets des perturbations electromagnétiques sur les canalisations causées par les
systèmes de traction électrique ferroviaire en courant alternatif et/ou par les réseaux
électriques H.T. en courant alternatif
Ta slovenski standard je istoveten z: EN 50443:2011
ICS:
23.040.99 Drugi sestavni deli za Other pipeline components
cevovode
29.280 (OHNWULþQDYOHþQDRSUHPD Electric traction equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 50443
NORME EUROPÉENNE
December 2011
EUROPÄISCHE NORM
ICS 23.040.99; 29.280; 33.100.01

English version
Effects of electromagnetic interference on pipelines caused by high
voltage a.c. electric traction systems and/or high voltage a.c. power
supply systems
Effets des perturbations électromagnétiques sur Auswirkungen elektromagnetischer
les canalisations causées par les systèmes de Beeinflussungen von
traction électrique ferroviaire en courant alternatif Hochspannungswechselstrombahnen und/oder
et/ou par les réseaux électriques H.T. en courant Hochspannungsanlagen auf Rohrleitungen
alternatif
This European Standard was approved by CENELEC on 2011-10-24. 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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management Centre 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

© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50443:2011 E
Contents
Foreword . 4
1 Scope. 5
2 Normative references . 5
3 Terms and definitions . 6
4 Procedure . 9
5 Interference distance . 9
5.1 General . 9
5.2 Interference distance for normal operating conditions . 10
5.2.1 overhead a.c. power systems . 10
5.2.2 underground a.c. power systems . 10
5.3 Interference distance for fault condition . 10
5.3.1 General . 10
5.3.2 overhead a.c. power systems . 10
5.3.3 underground a.c. power systems . 10
5.4 Summary of the interference distances . 10
6 Interference situations. 11
7 Coupling types . 11
8 Interference . 12
9 Interference results . 13
10 Limits for permissible interference . 13
10.1 General . 13
10.2 Limits related to electrical safety of persons . 13
10.2.1 General . 13
10.2.2 Operating conditions . 13
10.2.3 Fault conditions . 14
10.3 Limits related to damage to the pipeline system . 14
10.3.1 Fault conditions . 14
10.3.2 Operating conditions . 14
10.4 Limits related to disturbance of the pipeline system . 14
11 Evaluation of the interference results . 14
12 Mitigation measures . 15
Annex A (informative) Indications to select interference situations . 16
Annex B (informative) Guidance for interference investigations . 17
B.1 Introduction . 17
B.2 Configuration of the a.c. electric traction system . 17
B.3 Configuration of the a.c. power supply system . 18
B.4 Configuration of the pipeline . 18
B.5 Calculation methods . 19
B.6 Calculation of independent interfering systems . 20
Annex C (informative) Measuring methods. 21
C.1 General . 21
C.2 Measurement methods for interference voltages at steady state . 21
Annex D (informative) Mitigation measures . 22
D.1 General . 22
D.2 Mitigation measures at the pipeline side . 22
D.3 Mitigation measures at the a.c railway system side . 23
D.4 Mitigation measures at the a.c. power supply system side. 23
Annex E (informative) Management of interference . 24
E.1 General . 24
E.2 Plant life . 24
E.3 Exchange of information . 24
E.4 Plant documentation . 24

– 3 – EN 50443:2011
Annex F (informative) A-deviations . 26
Bibliography . 27

Tables
Table 1  Interference distances . 11
Table 2  Coupling types and distances to be considered . 12
Table 3  Limits for interference voltage related to danger to (electrically) instructed persons . 14

Foreword
This document (EN 50443:2011) has been prepared by Technical Committee CLC/TC 9XC "Electric
supply and earthing systems for public transport equipment and ancillary apparatus (Fixed installations)".

This European Standard gives limits relevant to the electromagnetic interference produced by high
voltage a.c. railway and power supply systems on metallic pipelines.
Limits are relevant to the interference which can be tolerated on the metallic pipeline, by the equipment
connected to it and by persons working on them or in contact with them.

This European Standard indicates the electromagnetic interference situations to which the limits must be
related.
Suggestions concerning the interference situations to be examined are given in Annex A. Suggestions
concerning the appropriate calculation methods are given in Annex B. Suggestions concerning the
appropriate measurement methods are given in Annex C. Suggestions about the use of mitigation
measures are given in Annex D. Suggestions for management of interference are given in Annex E.

The following dates are fixed:

– latest date by which the amendment has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2012-10-24

– latest date by which the national standards conflicting
with the amendment have to be withdrawn (dow) 2014-10-24

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
– 5 – EN 50443:2011
1 Scope
The presence of a.c. power supply systems or of a.c. electric traction systems (in this standard also
indicated as a.c. power systems) may cause voltages to build up in pipeline systems, (in this standard
indicated as interfered systems) running in the close vicinity, due to one or more of the following
mechanisms:
− inductive coupling,
− conductive coupling,
− capacitive coupling.
Such voltages may cause danger to persons, damage to pipelines or connected equipment or
disturbance to the electrical/ electronic equipment connected to the pipeline.

This European Standard deals with the situations where these effects may arise and with the maximum
tolerable limits of the interference effects, taking into account the behaviour of the a.c power systems
both in normal operating condition and/or during faults.

NOTE In the worst case, the pipe may not disperse current to ground. As a consequence, the prospective touch voltage
coincides with the interference voltage.

This European Standard applies to all metallic pipelines irrespective of the conveyed fluid, e.g. liquid or
gas, liable to be interfered by high voltage a.c. railway and high voltage a.c. power supply systems.

The objective of this standard is to establish:
− the procedure for evaluating the electromagnetic interference;
− the interference distance to be considered;
− the types of coupling to be considered for operating and fault conditions of the high voltage a.c.
electric traction systems and high voltage a.c. power supply systems;
− the configurations to be considered for both metallic pipeline and high voltage a.c. electric traction
systems or high voltage a.c. power systems;
− the limits of the voltages due to the electromagnetic interference;
− information on interference situations, calculation methods, measuring methods, mitigation measures,
management of interference.
This European Standard is applicable to all new metallic pipelines and all new high voltage a.c. electric
traction systems and high voltage a.c. power supply systems and all major modifications that may change
significantly the interference effect.

This European Standard only relates to phenomena at the fundamental power frequency (e.g. 50 Hz or
16,7 Hz).
This European Standard does not apply to:
− all aspects of corrosion,
− the coupling from a.c. railway and power supply systems with nominal voltages less than or equal to
1 kV,
− interference effects on the equipment not electrically connected to the pipeline.

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 60050-161, International Electrotechnical Vocabulary  Chapter 161: Electromagnetic
compatibility
IEC 60050-195, International Electrotechnical Vocabulary  Part 195: Earthing and protection
against electric shock
IEC 60050-826, International Electrotechnical Vocabulary  Part 826: Electrical installations

3 Terms and definitions
For the purposes of this document, the terms and definitions given in the International Electrotechnical
Vocabulary (IEV) apply, unless they are defined in this European Standard:

3.1
a.c. electric traction system
a.c. railway electrical distribution network used to provide energy for rolling stock
NOTE The system may comprise:
- contact line systems,
- return circuit of electric railway systems,
- running rails of non-electric railway systems, which are in the vicinity of, and conductively connected to the running rails of an
electric railway system.
3.2
a.c power supply system
a.c. electrical system devoted to electrical energy transmission and including overhead lines, cables,
substations and all apparatus associated with them
NOTE This includes HV transmission lines with 16,7 Hz.

3.3
a.c. power system
a.c. electric traction system or a.c. power supply system
NOTE Where it is necessary to differentiate, each interfering system is clearly indicated with its proper term.

3.4
interfering system
general expression encompassing an interfering high voltage a.c. electric traction system and/or high
voltage a.c. power supply system

3.5
interfered system
system on which the interference effects appear
NOTE In this standard pipeline system.

3.6
pipeline system
system of pipe network with all associated equipment and stations
NOTE 1 In this standard pipeline system refers only to metallic pipeline system.
NOTE 2 The associated equipment is the equipment electrically connected to the pipeline.

3.7
earth
conductive mass of the earth, whose electric potential at any point is conventionally taken as equal to
zero
[IEC 60050-826-04-01]
– 7 – EN 50443:2011
3.8
operating condition
fault free operation of any system
NOTE Transients are not to be considered as an operating condition.

3.9
fault condition
non intended condition caused by short-circuit to earth, the fault duration being the normal clearing time
of the protection devices and switches
NOTE The short circuit is an unintentional connection of an energized conductor to earth or to any metallic part in contact with
earth.
3.10
conductive coupling
coupling which occurs when a part of the current belonging to the interfering system returns to the system
earth via the interfered system or when the voltage to the reference earth of the ground in the vicinity of
the influenced object rises because of a fault in the interfering system, and the results of which are
conductive voltages and currents

3.11
inductive coupling
phenomenon whereby the magnetic field produced by a current carrying circuit influences another circuit;
the coupling being quantified by the mutual impedance of the two circuits, and the results of which are
induced voltages and hence currents that depend for example on the distances, length, inducing current,
circuit arrangement and frequency

3.12
capacitive coupling
phenomenon whereby the electric field produced by an energized conductor influences another
conductor, the coupling being quantified by the capacitance between the conductors and the
capacitances between each conductor and earth, and the results of which are interference voltages into
conductive parts or conductors insulated from earth, these voltages depending for example on the
voltage of the influencing system, distances and circuit arrangement

3.13
interference
phenomenon resulting from conductive, capacitive, inductive coupling between systems, and which can
cause malfunction, disturbance, danger, damage, etc.

3.14
disturbance
malfunction of an equipment loosing its capability of working properly for the duration of the interference
NOTE When the interference disappears, the interfered system starts again working properly without any external intervention.

3.15
damage
permanent reduction in the quality of service which can be offered by the interfered system
NOTE 1 Examples of damages are: coating perforation, pipe pitting, pipe perforation, permanent malfunction of the equipment
connected to the pipes, etc.
NOTE 2 A reduction in the quality of service may be also the complete cancellation of service.

3.16
interference situation
situation in which an interference may appear (permanently or intermittently) between an a.c. power
system and a metallic pipeline system, a given interference situation being defined by the geometrical
and electrical data of the a.c. power system and of the metallic pipeline system as well as defined by the
data describing the medium between the two systems
NOTE An interference situation may cause:
− danger to persons;
− damage to the pipeline and/or to the connected equipment;
− disturbance of the electrical and/or electronic equipment connected to the pipeline.

3.17
interference distance
maximum distance between the pipeline system and a.c. power system for which an interference shall be
considered
3.18
interfering current
vectorial sum of the currents flowing through the conductors relevant to the a.c. power system (i.e.
catenaries, feeders, return conductors, phase conductors, earth wires)
NOTE This interfering current is used to simplify the calculations when the distances between the interfering system and the
interfered system is high as compared to the distances between the conductors of the interfering system.

3.19
interference voltage
voltage caused on the interfered system by the conductive, inductive and capacitive coupling with the
nearby interfering system between a given point and the earth or across an insulating joint

3.20
prospective touch voltage
voltage between simultaneously accessible conductive parts when those conductive parts are not being
touched by a person or an animal
NOTE In the case dealt in this standard the prospective touch voltage coincides with the interference voltage. This is due to the
fact that in the worst case the interfered pipe may not disperse current to ground.
[IEC 60050-195-05-09]
3.21
skilled person
person with relevant education and experience to enable him or her to perceive risks and to avoid
hazards which electricity can create
[IEC 60050-195-04-01]
3.22
(electrically) instructed person
person adequately advised or supervised by electrically skilled persons to enable him or her to perceive
risks and to avoid hazards which electricity can create
[IEC 60050-195-04-02]
3.23
immunity
ability of a device, equipment or system to perform without degradation in the presence of an
electromagnetic disturbance
[IEC 60050-161]
– 9 – EN 50443:2011
3.24
environmental reduction factor
factor which represents the reduction of interference voltage associated with the presence of extended
earthed extraneous metallic structures
NOTE The value of the environmental reduction factor depends on many parameters (e.g. impedance of the circuit made of the
structure and the earth).
3.25
reduction factor
factor which represents the reduction of interference voltage associated with the presence of the current
flowing through the tracks, the return conductors, the cable shields, the shield wires, etc.

3.26
rural area
area which has a low density of local metallic structures in direct electrical contact with the soil

3.27
urban area
area which contains a high density of local metallic structures in direct electrical contact with the soil such
as water pipes, cables with bare metal sheaths, railway tracks, earthing structures of buildings, masts
and foundations
4 Procedure
In order to evaluate the acceptability of an interference produced by an a.c. power system on a metallic
pipeline system, the following design steps apply:
a) define the interference distance to be considered, according to Clause 5;
b) define the interference situations to be examined (worst cases of interference), according to
Clause 6;
c) select the involved coupling type(s) to be considered, according to Clause 7;
d) select the involved interference effect(s) to be considered, according to Clause 8;
e) assess the interference result(s) for each effect selected in the previous step, according to Clause 9;
f) select the acceptable limit for each of the results assessed in the previous step, according to
Clause 10;
g) determine the interference results on the metallic pipeline system by calculation or measurement,
according to Clause 11;
h) compare the interference results with the relevant limits; if the comparison shows that the
interference situation is unacceptable, mitigation measures shall be applied, according to Clause 12.

The procedure shall be carried out twice, i.e. considering short term interference (due to a.c. power
system in fault conditions) and long term interference (due to a.c. power system in operating conditions).

The design steps shall be supported and agreed by the involved parties.

5 Interference distance
5.1 General
The a.c. power systems located at a distance less than or equal to the interference distance from a given
metallic pipeline system shall be considered as interfering systems for this pipeline system.

The objective of interference distance is to limit the number of interfering systems to be considered and
for which assessing the interfering currents/voltages is necessary.

National rules, recommendations and guidelines determining other interference distances may be
applied.
NOTE 1 An alternative method for evaluating the interfering distances is presented in Annex A of Recommendation
ITU-T K.68:2008.
NOTE 2 The soil resistivity to be taken into account in defining the value of the interference distance is the one of the deep layers
of soil (as deep as needed for interference calculations).

5.2 Interference distance for normal operating conditions
5.2.1 overhead a.c. power systems
In rural areas, for soil resistivity below 3 000 Ωm, an interference distance of 1 000 m between the
interfering system and the metallic pipeline system should be considered. In case of soil resistivity value
greater than 3 000 Ωm, the interference distance value, in metres, should be equal to the soil resistivity
value, in Ωm, divided by 3.
In urban areas, the previous interference distance may be decreased, taking into account the
environmental reducing factor of the metallic structures existing in these areas. The interference distance
should not be less than 300 m.

NOTE Typical values for the environmental reducing factor are 0,1 to 0,7 (see ITU-T K.68:2008, Appendix II).

5.2.2 underground a.c. power systems
For underground a.c. power systems the interference distance should be 50 m.

5.3 Interference distance for fault condition
5.3.1 General
For a.c. power supply systems, the hereunder distances apply in the case of neutral solidly earthed or
earthed through small impedance.

The fault current values associated with insulating and resonant earthed systems are low and do not
result in danger or in significant risk of damage or disturbance and calculations or measurements are only
required when interference occurs.

5.3.2 overhead a.c. power systems
In rural areas, for soil resistivity below 3 000 Ωm, an interference distance of 3 000 m between the
interfering system and the metallic pipeline system should be considered. In case of soil resistivity value
greater than 3 000 Ωm, the interference distance value, in metres, should be equal to the soil resistivity
value in Ωm.
In urban areas, for soil resistivity below 3 000 Ωm, the interference distance should not be less than
300 m. For soil resistivity greater than 3 000 Ωm the interference distance, in metres, should be equal to
the soil resistivity value, in Ωm, divided by 10.

5.3.3 underground a.c. power systems
For underground a.c. power systems the interference distance should be 50 m.

5.4 Summary of the interference distances
Table 1 summarises the above statements.

– 11 – EN 50443:2011
Table 1  Interference distances
a
Interference distance
ρρρρ
Type of a.c. power
m
Areas
systems
Ω m
Normal operation Fault condition
> 3 000
ρ/3 ρ
overhead Rural
≤ 3 000 1 000 3 000
> 3 000
ρ/10
overhead Urban
≥ 300
≤ 3 000
≥ 300
underground all all 50 50
a
National rules, recommendations and guidelines determining other interference distances may be applied.

6 Interference situations
When dealing with a metallic pipeline system interfered by an a.c. power system, only interferences
below the limits indicated in chapter 10 are acceptable.

In general, several interference situations within the interference distance should be investigated, in order
to be sure that all the possible unacceptable interferences, if any, are turned into acceptable ones, by
adopting suitable mitigation measures as indicated in Annex D.

In Annex A suggestions are given on how to select the set of interference situations to be investigated.
Some suggestions about configuration and input data are given in informative Annex B.
7 Coupling types
Table 2 defines the coupling types requiring calculation and/or measurement for evaluating the
acceptability of the interference situation and maximum distances to be considered for the calculations.
Distances correspond to a compromise between the results of calculations and the experience of the
operators. The values refer to the limits of the interference voltages indicated in Table 3.

Table 2  Coupling types and distances to be considered
Metallic pipeline system
Above ground
Underground
Not electrically Electrically
connected to earth connected to earth
Normal Fault Normal Fault Normal Fault
operation condition operation condition operation condition
f f f f f f
Inductive Inductive Inductive Inductive Inductive Inductive
a b
Capacitive --- --- --- --- ---
c d c e c d c e
--- --- Conductive Conductive Conductive Conductive

a
Capacitive coupling from a railway system has to be considered in case of proximity lower than:
- 10 m in case of 15 kV, 16,7 Hz systems;
- 50 m in case of 25 kV, 50 Hz systems.

b
Capacitive coupling from a.c. power supply systems shall be considered in case of proximity lower than 100 m.

c
Conductive coupling from an a.c. electric traction system shall be considered in case of crossing or proximity lower than 5 m from
the nearest rail or masts or metallic components connected to the rails.
For faults in the HV side of an a.c. substation supplying an a.c. electric traction system, conductive coupling shall be considered
in case of proximity lower than 150 m from the earthing grid.

d
Not to be considered for the a.c. power supply systems.

e
To prevent damages to the pipeline or to the connected equipment, the following conditions apply:
Conductive coupling from a.c. power supply systems shall be considered in case of proximity lower than:
- 5 m from the closest visible part of the tower of a HV power line rated at 50 kV or less;
- 20 m from the closest visible part of the tower of a HV power line provided with earth wire(s) with nominal voltage greater than
50 kV;
- 100 m from the closest visible part of the tower of a HV power line not provided with earth wire(s) with nominal voltage greater
than 50 kV;
- 20 m from earthing systems of HV power cables with nominal voltage greater than 50 kV;
- 150 m from the earthing grid of a power substation.
In any case a minimum distance of 2 m from the closest part of the earthing system of a tower shall be observed.

To guarantee the electrical safety of persons, in case any metallic part connected to the pipeline is accessible to them,
conductive coupling has to be considered within the interference distance defined in Clause 5.

f
The interference distances are equal to the ones indicated in Clause 5.

NOTE It is assumed that fault current values associated with insulating and resonant earthed systems are low and do not result in
danger or in significant risk of damage or disturbance and calculations or measurements are only required when interference
occurs.
For pipelines without longitudinal electrical continuity, e.g. cast iron pipelines, interference effects are
usually negligible.
8 Interference
The effects to be considered are the following:
a) danger to persons who come in direct contact or contact through conductive parts with the metallic
pipeline system or with the connected equipment;
b) damage to the pipeline or to the connected equipment;
c) disturbance of electrical/electronic equipment, connected to the pipeline.

The pipeline company shall apply electrical/electronic systems such that they will not react in dangerous
ways, nor in ways which will stop production, to the short duration voltages not exceeding the values
defined in paragraph 10.3.1 and currents which appear during short circuits on the a.c. power system.

– 13 – EN 50443:2011
9 Interference results
The following interference results shall be evaluated:
a) for danger to persons who come in direct contact or in contact through conductive parts with the
metallic pipeline system or to the connected equipment, the voltage to earth of the pipeline and the
voltage difference on the insulating joints shall be evaluated in normal operation and in fault
conditions;
b) for damage to pipeline or to the connected equipment, the voltage to earth of the pipeline and the
voltage difference on the insulating joints shall be evaluated in normal operation and in fault
conditions;
c) for disturbance of electric/electronic equipment connected to the pipeline the voltage across the
electric/electronic equipment connected to the pipeline at the connection points shall be evaluated in
normal operation only.
10 Limits for permissible interference
10.1 General
Limits given in the following clauses apply:
− to the total interference result, produced on a single pipeline, or pipeline system, by all the a.c.
interfering systems acting together, when considering the operating conditions of the interfering
sources;
− to the interference result, produced on a single pipeline, or pipeline system, by a single a.c. interfering
system acting alone, when considering the fault conditions of the interfering system.

NOTE An interfering system may be composed of many interconnected lines.

10.2 Limits related to electrical safety of persons
10.2.1 General
The limits stated in 10.2.2 and in 10.2.3:
− apply to those parts of the metallic pipeline or connected equipment normally accessible to
(electrically) instructed persons, all along the pipeline,
− refer to instructed persons with common clothing, without particular individual protection means other
than shoes with an insulating resistance not less than 3 000 Ω. In case of use of individual protection
means a specific study shall evaluate the admissible values for the interference voltages, which can
be higher than the ones given in 10.2.2 and in 10.2.3.

The permissible voltages given in 10.2.2 and in 10.2.3 are in accordance with typical situation and
working procedures (see ITU-T K.68).

In case of more severe situations (wet conditions, narrow working space, repairing operations, etc.) or
where common people (i.e. neither electrically instructed nor skilled persons) may come in contact with
the pipeline in operating conditions, additional precautions should be taken into consideration (e.g.
reduce admissible voltage, use of insulating coverings, special instruction to personnel, etc).

The voltage to ground limits hereunder specified refer to interference voltages.

10.2.2 Operating conditions
The interference voltage (r.m.s. value) of the pipeline system versus earth or across the insulating joints
at any point normally accessible to any person (see 10.2.1) shall not exceed 60 V.

10.2.3 Fault conditions
The interference voltage (r.m.s. value) of the pipeline system versus earth or across the insulating joints
at any point normally accessible to (electrically) instructed persons shall not exceed the values given in
Table 3. Table 3 takes into consideration the specific situation of handling of pipelines and connected
equipment.
Table 3  Limits for interference voltage related to danger to (electrically) instructed
persons
Fault duration Interference voltage
(r.m.s. value)
t
s V
2 000
t ≤ 0,1
1 500
0,1 < t ≤ 0,2
0,2 < t ≤ 0,35 1 000
0,35 < t ≤ 0,5 650
0,5 < t ≤ 1,0
1 < t ≤ 3
t > 3 60
10.3 Limits related to damage to the pipeline system
10.3.1 Fault conditions
− The interference voltage (r.m.s. value) between the metallic pipeline system and the earth at any point
of the pipeline system, or the interference voltage (r.m.s. value) between any element of the
electric/electronic equipment connected between the metallic pipeline and the earth, shall not exceed
2 000 V;
− The voltage difference (r.m.s. value) across an insulating joint shall not exceed 2 000 V.

Values greater than 2 000 V can be accepted if the plant is able to withstand such values and if there is
an agreement on that.
10.3.2 Operating conditions
Under operating conditions the interference voltage (r.m.s. value) between any point of the metallic
pipeline system and the earth or the voltage between any element of the electric/electronic equipment
connected to the metallic pipeline and the earth shall not exceed 60 V.

10.4 Limits related to disturbance of the pipeline system
In operating conditions, an interference voltage (r.m.s. value) of 60 V between the metallic pipeline
system and the earth shall be permitted without disturbing electric/electronic equipment connected
between the metallic pipeline and the earth and an interference voltage (r.m.s. value) of 60 V across the
insulating joints shall be permitted without disturbing electric/electronic equipment connected across the
insulating joint.
11 Evaluation of the interference results
When dealing with a metallic pipeline system interfered by an a.c. power system, only acceptable
interferences are allowed.
Interference results shall be evaluated through calculation or measurement.

– 15 – EN 50443:2011
Each company involved in the interference is responsible for providing correct data relevant to its
systems involved.
Some suggestions concerning input data and calculation are given in Annex B.

Measurements are also used to evaluate the interference results. Measurement results can be directly
compared with the limits only if the measurements are performed in the same interference condition to
which limits apply. If this is not the case, measurements require a suitable elaboration based on
calculation methods and on measurements performed at the same time on both the a.c. power system
and the pipeline system.
Some suggestions concerning measurement methods are given in Annex C.

The calculation methods and the measurement methods shall be agreed between the power and/or
railway infrastructure manager and the pipeline company.

Where measurements are to be carried out, they shall be coordinated between the involved parties.

To take into account all the electromagnetic interferences acting together see Annex B.

12 Mitigation measures
In case interference results exceed the limits, mitigation measures shall be agreed on by the involved
parties, in order to make the interference situation acceptable.

NOTE Which measures are taken and whether the measures are taken on the interfering or on the interfered system, will depend
on the significance of the interference, the impact in terms of safety, equipment damage and malfunction, cost and complexity of
mitigation options and the party introducing the change.

Some suggestions concerning mitigation measures are given in Annex D.

Annex A
(informative)
Indications to select interference situations
The scope of the interference evaluation and mitigation is to get assurance that only acceptable
interferences occur.
In general, several interference situations should be investigated within the interference distance, in order
to be sure that all the possible unacceptable interferences, if any, are turned into acceptable ones, by
adopting suitable mitigation measures.

In general it is impossible to give rules for defining the set of interference situations to be examined.
During the design procedure it is necessary to examine an adequate set of interference situations in
order to be sure that, after the design stage, unacceptable interferences exist no more.

In some cases, characterized by simple configurations of the involved systems, it can be possible to
define a priori, before making interference calculations, the worst interference situation, resulting in the
highest value of interference results.

This is the case, e.g., of fault condition on “simple” power systems (e.g. a simple a.c. railway line is the
one where trains are fed by the contact wire only and the current return is made through rails and earth
only, without special arrangements like return conductors, booster transformers or autotransformers),
where, usually, the worst fault position is the one corresponding to the one of the ends of the exposure
zone.
In the majority of cases the worst interference situation can be evaluated only after making several
calculations. Thus in the design procedure an adequate set of calculations has to be selected in order to
be sure that it comprises the worst case.

Interference problems can arise not only when the metallic pipeline system is completed, but also during
the installation stage, even if at that stage only some parts of the whole metallic pipeline system are
involved in the coupling phenomena.

– 17 – EN 50443:2011
Annex B
(informative)
Guidance for interference investigations
B.1 Introduction
It should be considered that a calculation method able to evaluate the results of interference requires a
lot of input data and a variety of algorithms. Thus it is impossible to give a description of one or more
calculation methods as a normative part of this standard. This is the reason why we give in this
informative Annex B some suggestions only, which can be used to carefully select, according to the
interference problem to be solved, the specific calculation method to be used.

If national rules concerning calculations exist, they should be applied.

B.2 Configuration of the a.c. electric traction system
B.2.1 General
As a general rule, the closer the inducing railway line is to the induced pipeline, the greater the number of
parameters describing the railway line is required.

The fundamental parameters to be known for evaluating at one frequency the interference results should
be:
a) in case the approach distance is less than 100 m and the length of parallelism is greater than
1 000 m within this distance:
1) the current flowing in all relevant conductors and tracks for the considered frequency;
2) the geometrical position of all relevant conductors;
3) the geographic position of the line;
b) in other cases, when the distance between railway line and pipeline is longer:
1) the interfering current for the considered frequency;
2) the geographic position of the line.
Instead of the current flowing in the tracks or in conductors other than the contact wire, the relevant
reduction factors may be used.

NOTE T
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