《AS-NZS-4853-2000.pdf》由会员分享，可在线阅读，更多相关《AS-NZS-4853-2000.pdf（68页珍藏版）》请在三一文库上搜索。
1、AS/NZS 4853:2000 Australian/New Zealand Standard Electrical hazards on metallic pipelines AS/NZS 4853 AS/NZS 4853:2000 This Joint Australian/New Zealand Standard was prepared by Joint Technical Committee EL/1, Wiring Rules. It was approved on behalf of the Council of Standards Australia on 3 Novembe
2、r 2000 and on behalf of the Council of Standards New Zealand on 27 October 2000. It was published on 1 December 2000. The following interests are represented on Committee EL/1: The Association of Consulting Engineers Australia Australian Building Codes Board Australian Electrical and Electronic Manu
3、facturers Association Communications, Electrical Plumbing Union Electrical Contractors Association of New Zealand Electrical Contractors Association Qld Electrical Safety Organisation (New Zealand) Electricity Supply Association of Australia Institute of Electrical Inspectors Institution of Engineer
4、s Australia Insurance Council of Australia Limited Ministry of Commerce New Zealand National Electrical and Communications Association New Zealand Council of Elders New Zealand Electrical Institute Regulatory authorities (electrical) Telstra Corporation Limited Additional interests participating in
5、the preparation of this Standard: Cathodic Protection Consultants/Installers Electrical Protection Engineers Gas Suppliers Pipe Manufacturers Pipeline Installers Pipeline Operators Railways Water Authorities Keeping Standards up-to-date Standards are living documents which reflect progress in scienc
6、e, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should
7、include any amendments which may have been published since the Standard was purchased. Detailed information about joint Australian/New Zealand Standards can be found by visiting the Standards Australia web site at .au or Standards New Zealand web site at www.standards.co.nz and looking up the releva
8、nt Standard in the on-line catalogue. Alternatively, both organizations publish an annual printed Catalogue with full details of all current Standards. For more frequent listings or notification of revisions, amendments and withdrawals, Standards Australia and Standards New Zealand offer a number of
9、 update options. For information about these services, users should contact their respective national Standards organization. We also welcome suggestions for improvement in our Standards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. Please ad
10、dress your comments to the Chief Executive of either Standards Australia International or Standards New Zealand at the address shown on the back cover. This Standard was issued in draft form for comment as DR 99086. AS/NZS 4853:2000 Australian/New Zealand Standard Electrical hazards on metallic pipe
11、lines First published as AS/NZS 4853:2000. COPYRIGHT Standards Australia/Standards New Zealand All rights are reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Joi
12、ntly published by Standards Australia International Ltd, GPO Box 5420, Sydney, NSW 2001 and Standards New Zealand, Private Bag 2439, Wellington 6020 ISBN 0 7337 3683 1 AS/NZS 4853:2000 2 PREFACE This Standard was prepared by the Joint Standards Australia/Standards New Zealand Committee EL-001, Wirin
13、g Rules. The objective of this Standard is to provide guidelines on how to limit the electrical hazards which may appear on metallic pipelines, to identify some additional safeguards which may be necessary, and to specify acceptable electrical limits on pipelines. This Standard also provides a range
14、 of informative appendices (which is not intended to be exhaustive) on the following subjects, which have a bearing on the application of the Standard: (a) Sample methods of calculation of induced and other voltages from high voltage power lines and a.c. electric rail on pipelines. (b) Methods of co
15、ntrolling or reducing the induced or coupled voltages on pipelines, to achieve the prescribed values. (c) Precautions available to mitigate hazards due to fault conditions on the high voltage system. (d) The interaction of cathodic protection systems with protective earthing systems and some suggest
16、ed means of resolving the resultant problems. (e) Check lists of data that may be required for calculation of low frequency induction (LFI) from the electricity transmission organization and from the pipeline owner or authority. (f) Pipeline lightning protection. (g) A brief bibliography on the tech
17、nical matters addressed in this Standard. During preparation of this Standard, reference was made to documentation provided by Brisbane Water and acknowledgment is made of their assistance. The terms normative and informative have been used in this Standard to define the application of the appendix
18、to which they apply. A normative appendix is an integral part of a Standard, whereas an informative appendix is only for information and guidance. Symbols used in equations in this Standard are defined in relation to the particular equations in which they occur. AS/NZS 4853:2000 3 CONTENTS Page FORE
19、WORD4 1 SCOPE5 2 APPLICATION.5 3 REFERENCED DOCUMENTS5 4 DEFINITIONS5 5 ACCEPTABLE VOLTAGE LIMITS5 6 LOW FREQUENCY INDUCTION (LFI).9 7 CAPACITIVE COUPLING 12 8 EFFECTS OF LIGHTNING13 9 CONDUCTIVE EFFECTEARTH POTENTIAL RISE (EPR).14 10 OTHER HAZARDS15 11 INTERACTION BETWEEN PROTECTIVE EARTHING SYSTEM
20、S ON PIPELINES AND CATHODIC PROTECTION SYSTEMS.17 12 COMMISSIONING AND MAINTENANCE OF PIPELINE EARTHING SYSTEMS17 APPENDICES A LIST OF REFERENCED DOCUMENTS19 B DEFINITIONS.20 C LOAD CURRENT LFI EXAMPLE CALCULATION.22 D FAULT CURRENT LFI EXAMPLE CALCULATION.25 E EFFECTS OF A.C. TRACTION SYSTEM ON A N
21、EARBY PIPELINE.34 F PIPELINE LOOP IMPEDANCE .39 G SAMPLE CALCULATION OF INTERCEPTED CAPACITIVE CURRENT.45 H EPR NEAR A HIGH VOLTAGE INSTALLATION .48 I MECHANICAL HANDLING OF PIPE LENGTHS 59 J INTERACTION OF CATHODIC PROTECTION SYSTEMS WITH PIPELINE PROTECTIVE EARTHING SYSTEMS61 K BIBLIOGRAPHY63 AS/N
22、ZS 4853:2000 4 FOREWORD To utilize land effectively, it is common to use easements for both high voltage power lines and pipelines. This close proximity of high voltage power lines and pipelines can result in voltages being induced onto the pipeline from a number of external influences. Although ove
23、rland transmission lines and metallic pipelines have been laid and constructed in the same easements for many years, the continuous growth of energy consumption, with increases in voltages, load currents and fault capacities, has resulted in an increase in the electrical and physical problems. The a
24、doption of modern pipeline insulating coatings has exacerbated these problems. There is a growing concern about the following aspects: (a) Safety of people making contact with the pipeline. (b) Risk of damage to the pipeline coating and metal. (c) Risk of damage to equipment such as the pipeline cat
25、hodic protection (CP) system and telemetry systems. This Standard considers a number of circumstances which give rise to electrical conditions on pipelines. (i) Low frequency induction (LFI) due to parallel or near parallel positioning of the pipelines and high voltage power lines or high voltage a.
26、c. traction systems. (ii) Earth potential rise (EPR) due to pipeline proximity with high voltage power line towers, substation earth mats, and other earthing current discharge points. (iii) EPR due to lightning current following flash attachment to objects or structures adjacent to the pipelines. (i
27、v) Capacitive coupling due to the placing, temporarily or permanently, of pipelines sufficiently adjacent to high voltage power lines to intercept a significant proportion of their electric field. (v) The effects of lightning current introduced to the pipeline, directly or indirectly, and the effect
28、s due to the electrical properties of the pipeline and its coating. (vi) The fortuitous contact of pipelines with other electrical systems such as electricity distribution or traction systems. AS/NZS 4853:2000 COPYRIGHT 5 STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND Australian/New Zealand Standard Elec
29、trical hazards on metallic pipelines 1 SCOPE This Standard specifies voltage limits and corresponding time constraints acceptable on both underground and above-ground pipelines that may be subject to power system influences. Guidance on the mitigation of lightning flash attachments is also provided.
30、 NOTE: The acceptable voltage and time limits are based on the conditions outlined in AS 3859. This Standard describes the mechanisms which create hazardous electrical conditions on such pipelines and provides guidance on how to calculate and mitigate these hazards. This Standard does not cover elec
31、trical hazards on electricity power plant associated with the construction of pipelines and their coatings. Such hazards are covered by AS/NZS 3000 and its associated Standards. 2 APPLICATION This Standard is applicable to those pipelines with electrically conducting walls, usually steel, and with a
32、n aqueous slurry or hydrocarbon-based product content such as water, oil or gas. The responsibility for the application of this Standard rests with the owner or operating authority of the pipeline and therefore they should seek competent advice with regards to its content. It is not intended that th
33、is Standard be applied retrospectively to installations existing at the date of publication of this Standard in so far as design, construction, operation, maintenance and testing are concerned. However, this Standard may be used during redesign or upgrading of existing pipelines to achieve conforman
34、ce. 3 REFERENCED DOCUMENTS The documents referred to in this Standard are listed in Appendix A. 4 DEFINITIONS For the purpose of this Standard the definitions listed in Appendix B apply. 5 ACCEPTABLE VOLTAGE LIMITS 5.1 General This Clause 5 sets out requirements for two categories of acceptable volt
35、age limits for pipelines. Requirements for Category A touch voltage limits are provided in Clause 5.3. Requirements for Category B touch voltage limits are provided in Clause 5.4. NOTES: 1 The voltage limits are touch voltage limits as defined in this Standard. 2 Pipelines which have touch voltages
36、above those given in Clause 5.4 are outside the scope of this Standard. Some indication of the nature of such voltages is provided in Clause 5.5. 3 Reference in other documents to the acceptable voltage limits given in this Standard may be achieved by the wording Category A (or Category B) touch vol
37、tage limits in accordance with AS/NZS 4853 (this Standard) as appropriate. AS/NZS 4853:2000 COPYRIGHT 6 4 There is a misconception that internationally agreed power and telecommunication induction and earth potential rise (EPR) limits are applicable generally to environmental safety. These limits ar
38、e as follows: (a) Voltage withstand for pulse conditions of affected telecommunications equipment is relatively high ( 1500 V). (b) Low risk conditions in telecommunications terminalsclear, dry, insulated floors and very small contact areas. (c) Very low coincident exposure (based on statistical ana
39、lysis). (d) Minute cost to telecom carriers to fit exposed circuits with gas tube protectors, which are often required to protect against lightning surges. Combined with high resistance circuits (50 1000 ohm), these offer high protection. These items are not applicable to pipeline technology. 5.2 Ri
40、sk assessment Acceptable Category A maximum touch voltage limits for accessible pipelines are given in Table 5.3. The voltages relate to electrical safety protection from electric shock. However, Category A touch voltage limits may be unnecessarily onerous on pipelines with totally restricted public
41、 access (e.g. high pressure gas transmission lines) and a risk assessment should be made to determine whether Category B touch voltage limits (Clause 5.4 and Table 5.4) may be permitted. NOTE: Guidance on risk management is given in AS/NZS 4360. Whilst the major point of the risk assessment is to de
42、termine the acceptability of Category B touch voltage limits, attention is drawn to the need for a risk assessment also for some aspects of installations with Category A touch voltage limits. The risk assessment shall be in two parts; one for pipelines accessible by the general public and the other
43、for pipelines only accessible to authorized persons. The risk assessment shall include the following: (a) Depth of burial of the pipeline. (b) Protection against loss of pipeline cover. (c) Electrical isolation of accessible sections of pipelines or other adequate protection. (d) Protection of catho
44、dic protection (CP) test points by equipotential mats or other appropriate means. (e) Design and location of any earthing system. (f) Frequency and duration of power system faults. (g) The location of the pipeline in relation to power system plant. (h) The accessibility of the pipeline. (i) The requ
45、irements of the appropriate regulators. (j) The need for appropriate signs. (k) Training of authorized personnel. (l) The need for the use of personal protection equipment such as special footwear or gloves. AS/NZS 4853:2000 COPYRIGHT 7 In assessing the risks associated with a substantial pipe to so
46、il voltage (e.g. 3000 V), account must be taken of the source and impedances of the origin of this voltage. For example, 3000 V from earth potential rise (EPR) due to a fault to a high voltage power line tower a few metres from a buried pipeline is of little consequence; a pipeline coating in good c
47、ondition should survive this condition. Minor leakage current from the soil to the pipeline is negligible. However 3000 V from low frequency induction (LFI) on a pipeline is energy imparted to the pipeline, at low impedance, and may travel for many kilometres along the pipeline, unless mitigated by
48、measures described in this Standard. The power level can be hundreds of kilowatts. Higher voltage short term electrical surges (e.g. 300 V 100 ms) in accordance with Table 5.3 would not normally be electrically hazardous in terms of AS 3859. However they can cause violent muscular reaction which cou
49、ld lead to physical injury (such as falling from a ladder or contact with power tools, etc). The assumptions, methodology and outcomes of the risk assessment shall be appropriately documented and retained. The risk assessment shall be revalidated whenever a change to the pipeline or its environment occurs or every five years whichever occurs first. The performance review outlined in Clause 12.4 should also be carried out at this time. NOTE: Where a section of pipeline is wholly underground, and isolated from all terminals and appurtenances, includin