BS EN 50162-2005 Protection against corrosion by stray current from direct current systems《直流系统中杂散电流引起腐蚀的防护》.pdf

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1、BRITISH STANDARD BS EN 50162:2004 Protection against corrosion by stray current from direct current systems The European Standard EN 50162:2004 has the status of a British Standard ICS 29.020; 77.060 BS EN 50162:2004 This British Standard was published under the authority of the Standards Policy and

2、 Strategy Committee on 19 January 2005 BSI 19 January 2005 ISBN 0 580 45265 4 National foreword This British Standard is the official English language version of EN 50162:2004. The UK participation in its preparation was entrusted by Technical Committee GEL/9, Railway electrotechnical applications,

3、to Subcommittee GEL/9/3, Fixed equipment, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document

4、may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. User

5、s are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change,

6、 and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 30, an inside back cover and a back cover. The BSI copyright notice

7、 displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 50162 NORME EUROPENNE EUROPISCHE NORM August 2004 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Ele

8、ctrotechnique Europisches Komitee fr 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 ICS 29.020; 77.060 English version Protect

9、ion against corrosion by stray current from direct current systems Protection contre la corrosion due aux courants vagabonds des systmes courant continu Schutz gegen Korrosion durch Streustrme aus Gleichstromanlagen This European Standard was approved by CENELEC on 2004-05-01. CENELEC members are bo

10、und 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

11、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 sam

12、e 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, Portug

13、al, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 50162:2004 - 2 - 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

14、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 con

15、flicting 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 interference8 5.1 Identification.8 5.2 Measurement .

16、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 Principles11 7.3 Direct current systems at industrial sites .11 7.4 Direct current systems at ports

17、11 7.5 Direct current communication systems12 7.6 Direct current traction systems 12 7.7 High-voltage direct current transmission systems .12 7.8 Cathodic protection systems13 7.9 Interference caused by electrical drainage (secondary interference)14 8 Reduction of stray current interference Modifica

18、tions 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 int

19、erference21 EN 50162:2004 - 4 - Annex C (informative) Criteria for maximum acceptable levels of potential shift U of anodic interference.23 Annex D (informative) The use of current probes to evaluate fluctuating stray current interference on cathodically protected structures24 Annex E (informative)

20、Interference situations and protection techniques.27 Bibliography30 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 anodi

21、c potential gradients (cathodic interference) .22 Figure D.1 - Measuring method24 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

22、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

23、 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 station29 Tables Table 1 Acceptable positive potential shifts U for buried or immersed metal structures which are not cathod

24、ically 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 structur

25、es (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 a

26、t 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

27、 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 corros

28、ion other measures have to be applied. EN 50162:2004 - 6 - 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:

29、 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 corr

30、osion 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 mea

31、sures 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 u

32、nintentional, 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

33、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) st

34、eel 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

35、, 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 applicati

36、on 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 stra

37、y 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 d

38、efinitions 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 f

39、rom 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 stru

40、cture 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 th

41、e transfer of current 3.5 unidirectional drainage bond device that provides electrical drainage by means of a unidirectional bond between the affected structure and the stray current source. The bond includes a device such as a diode to ensure that current can only flow in one direction EN 50162:200

42、4 - 8 - 4 Information exchange and co-operation During the design stage of buried or immersed metallic structures the possibility of both causing and suffering from stray current interference shall be taken into consideration in order to meet the criteria mentioned in Clause 6. Electrical interferen

43、ce problems on buried or immersed metallic structures shall be considered with the following points in mind: the owner of the metallic structure may protect a structure against corrosion with the method that he considers to be the most suitable. However, electrical interference to neighbouring struc

44、tures shall be maintained within the defined limits; stray currents, especially from d.c. traction systems are directly related to the design of the return circuits. This means that it is possible to limit the stray current but not to remove it entirely; where other structures that may be affected a

45、re present, the requirement to maintain interference within the defined limits applies to all affected structures. This goal is best achieved by agreement, co-operation and information exchange between the parties involved. Information exchange and co-operation are important and shall be carried out

46、 both at the design stage and during operation of the systems. In this way possible effects, suitable precautions and remedies can be assessed. The following information shall be exchanged: 1) details of new buried metallic structures; 2) cathodic protection installations or significant modification

47、s; 3) d.c. traction system installations or significant modifications; 4) HVDC transmission line installation or modification. Agreement and co-operation may be more effectively achieved and maintained by periodic meetings between interested parties, committees or other associations who can establis

48、h information exchange procedures and protocols. 5 Identification and measurement of stray current interference 5.1 Identification In cases where there is a possible corrosion risk due to d.c. interference analysis of the situation shall consider electrical properties and the location of the possibl

49、e source of interference as well as anomalies recorded during routine cathodic protection measurements. There are four principal ways to identify stray-current interference. These are to measure one or more of the following: structure to electrolyte potential fluctuations; deviations from normal structure to electrolyte potentials; voltage gradients in the electrolyte; line currents in pipelines coupons or metallic cable sheaths. NOTE The measurement