EN 50162:2004
(Main)Protection against corrosion by stray current from direct current systems
Protection against corrosion by stray current from direct current systems
This standard establishes the general principles to be adopted to minimize the effects of stray current corrosion caused by direct-current (d.c.) on buried or immersed metal structures. The standard is intended to offer guidance for: – the design of direct current systems which may produce stray currents; – the design of metal structures, which are to be buried or immersed and – which may be subject to stray current corrosion; – the selection of appropriate protection measures. The standard mainly deals with external stray current corrosion on buried or immersed structures. However stray current corrosion may also occur internally in systems containing an electrolyte e.g. near insulating joints or high resistance pipe joints in a water pipeline. These situations are not dealt with in detail in this standard but principles and measures described here are generally applicable for minimizing the interference effects. Stray currents may also cause other effects such as overheating. These are not covered in this standard. D.C. systems that can cause currents to flow in the earth or any other electrolyte, whether intentional or unintentional, include: – d.c. traction systems; – trolley bus systems; – d.c. power systems; – d.c. equipment at industrial sites; – d.c. communication systems ; – cathodic protection systems; – high voltage d.c. (HVDC) transmission systems; – d.c. track circuit signalling systems. For stray currents from traction systems EN 50122-2 gives requirements for minimizing their production and for the effects within the railroad. Systems which may be affected by stray currents include buried or immersed metal structures such as: a) pipelines; b) metal sheathed cables; c) tanks and vessels; d) earthing systems; e) steel reinforcement in concrete; f) steel piling. An affected structure carrying stray currents, e.g. a pipeline or cable may itself affect other nearby structures (see Clause 8). This standard does not address the effect of a.c. stray current. Where a.c. stray current is suspected, care should be taken when taking measurements on any components due to risk of large induced voltages. If a.c. stray current interference is present the criteria described in this standard will not apply.
Schutz gegen Korrosion durch Streuströme aus Gleichstromanlagen
Protection contre la corrosion due aux courants vagabonds des systèmes à courant continu
Železniške naprave – Zaščita proti koroziji zaradi učinkovanja blodečih tokov pri enosmernih tokovnih sistemih
General Information
Standards Content (Sample)
SLOVENSKI SIST EN 50162:2005
STANDARD
december 2005
Železniške naprave – Zaščita proti koroziji zaradi učinkovanja blodečih tokov
pri enosmernih tokovnih sistemih
Protection against corrosion by stray current from direct current systems
ICS 29.020; 77.060 Referenčna številka
© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno
EUROPEAN STANDARD EN 50162
NORME EUROPÉENNE
EUROPÄISCHE NORM August 2004
ICS 29.020; 77.060
English version
Protection against corrosion by stray current
from direct current systems
Protection contre la corrosion Schutz gegen Korrosion
due aux courants vagabonds durch Streuströme aus
des systèmes à courant continu Gleichstromanlagen
This European Standard was approved by CENELEC on 2004-05-01. 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, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and 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
© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50162:2004 E
Foreword
This European Standard has been prepared by CENELEC BTTF 114-1, Protection against corrosion
by stray current from direct current systems.
The text of the draft was submitted to the Unique Acceptance Procedure and was approved by
CENELEC as EN 50162 on 2004-05-01.
The following dates were fixed:
- latest date by which the EN has to be implemented
at national level by publication of an identical national
standard or by endorsement (dop) 2005-05-01
- latest date by which the national standards
conflicting with the EN have to be withdrawn (dow) 2007-05-01
- 3 - EN 50162:2004
Contents
Introduction .5
1 Scope .6
2 Normative references.7
3 Definitions.7
4 Information exchange and co-operation.8
5 Identification and measurement of stray current interference.8
5.1 Identification.8
5.2 Measurement .9
6 Criteria for stray-current interference .10
6.1 Anodic interference .10
6.2 Cathodic interference.10
7 Reduction of stray current interference – Modifications to current source.11
7.1 General .11
7.2 Principles.11
7.3 Direct current systems at industrial sites .11
7.4 Direct current systems at ports .11
7.5 Direct current communication systems.12
7.6 Direct current traction systems .12
7.7 High-voltage direct current transmission systems .12
7.8 Cathodic protection systems.13
7.9 Interference caused by electrical drainage (secondary interference).14
8 Reduction of stray current interference – Modifications to the interfered structure .15
8.1 General .15
8.2 Design prerequisites .15
8.3 Installation of mitigation devices .15
9 Inspection and maintenance .18
Annex A (informative) Stray current corrosion, potential measurements and IR-drop .19
Annex B (informative) Principles of anodic and cathodic interference.21
Annex C (informative) Criteria for maximum acceptable levels of potential shift ΔU of anodic
interference.23
Annex D (informative) The use of current probes to evaluate fluctuating stray current interference on
cathodically protected structures.24
Annex E (informative) Interference situations and protection techniques.27
Bibliography.29
Figures
Figure B.1 - Principle of interference due to d.c. operated railways .21
Figure B.2 - Principle of interference due to cathodic potential gradients (anodic interference) .21
Figure B.3 - Principle of interference due to anodic potential gradients (cathodic interference) .22
Figure D.1 - Measuring method.24
Figure D.2 - Example of the result of a probe current measurement („A“ indicates the period in
which the reference level is measured; „B“ indicates the period with the highest
reduction of the reference level). .25
Figure D.3 - Graphical representation of Table D.1 .26
Figure E.1 - Examples for secondary interference.27
Figure E.2 - Mitigation of interference using a drainage bond .27
Figure E.3 - Mitigation of interference using a unidirectional drainage bond.28
Figure E.4 - Mitigation of interference using a forced drainage bond .28
Figure E.5 - Mitigation of interference using an earthing electrode or a galvanic anode.29
Figure E.6 - Mitigation of interference using an impressed current station.29
Tables
Table 1 – Acceptable positive potential shifts ΔU for buried or immersed metal structures which
are not cathodically protected .10
Table D.1 – Current criteria in case of interference due to d.c. traction systems .26
- 5 - EN 50162:2004
Introduction
Stray currents originating from direct current systems may cause severe material damage by
corrosion, stray current corrosion, on buried or immersed metal structures (see Annex A). Particularly,
long buried horizontal structures, e.g. pipelines and metal sheathed cables, may be in danger of this
type of corrosion. Since corrosion damage can appear after only a short time of exposure to stray
current it is important to make provisions for protective measures at an early stage and also to check
the effect of these measures regularly.
This standard describes appropriate measures that can be applied to interfering d.c. systems and, if
necessary, to structures which are, or which can be, exposed to stray current corrosion. The standard
also gives measurement criteria for determining when these measures must be applied. Measurement
techniques used on d.c. interfered structures are described in EN 13509.
The measures described in this standard are aimed for protection against stray current corrosion. For
effective protection against other types of corrosion other measures have to be applied.
1 Scope
This standard establishes the general principles to be adopted to minimize the effects of stray current
corrosion caused by direct-current (d.c.) on buried or immersed metal structures.
The standard is intended to offer guidance for:
– the design of direct current systems which may produce stray currents;
– the design of metal structures, which are to be buried or immersed and
– which may be subject to stray current corrosion;
– the selection of appropriate protection measures.
The standard mainly deals with external stray current corrosion on buried or immersed structures.
However stray current corrosion may also occur internally in systems containing an electrolyte e.g.
near insulating joints or high resistance pipe joints in a water pipeline.
These situations are not dealt with in detail in this standard but principles and measures described
here are generally applicable for minimizing the interference effects.
Stray currents may also cause other effects such as overheating. These are not covered in this
standard.
D.C. systems that can cause currents to flow in the earth or any other electrolyte, whether intentional
or unintentional, include:
– d.c. traction systems;
– trolley bus systems;
– d.c. power systems;
– d.c. equipment at industrial sites;
– d.c. communication systems ;
– cathodic protection systems;
– high voltage d.c. (HVDC) transmission systems;
– d.c. track circuit signalling systems. For stray currents from traction systems EN 50122-2 gives
requirements for minimizing their production and for the effects within the railroad.
Systems which may be affected by stray currents include buried or immersed metal structures such
as:
a) pipelines;
b) metal sheathed cables;
c) tanks and vessels;
d) earthing systems;
e) steel reinforcement in concrete;
f) steel piling.
- 7 - EN 50162:2004
An affected structure carrying stray currents, e.g. a pipeline or cable may itself affect other nearby
structures (see Clause 8).
This standard does not address the effect of a.c. stray current. Where a.c. stray current is suspected,
care should be taken when taking measurements on any components due to risk of large induced
voltages. If a.c. stray current interference is present the criteria described in this standard will not
apply.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 50122-2:1998, Railway applications - Fixed installations - Part 2: Protective provisions against the
effects of stray currents caused by d.c. traction systems
EN 12954:2001, Cathodic protection of buried or immersed metallic structures – General principles
and application for pipelines
EN 13509:2003, Cathodic protection measurement techniques
3 Definitions
For the purposes of this European Standard, the terms and definitions given in EN 12954, EN 50122-2
and the following apply.
3.1
coating
electrically insulating covering bonded to a metal surface for protection against corrosion by
preventing contact between the electrolyte and the metal surface
3.2
drainage (electrical drainage)
transfer of stray current from an affected structure to the current source by means of a deliberate bond
NOTE For drainage devices see direct drainage bond, unidirectional drainage bond and forced drainage bond
3.3
direct drainage bond
device that provides electrical drainage by means of a direct bond between an affected structure and
the stray current source. The bond may include a series resistor to limit current
3.4
forced drainage bond
device that provides electrical drainage by means of a bond between an affected structure and the
stray current source. The bond includes a separate source of d.c. power to augment the transfer of
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.