Protection of telecommunication lines using metallic symmetric conductors against lightning-induced surges |
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Recommendation ITU-T K.46 gives a procedure to protect telecommunication lines using metallic symmetric conductors (i.e., twisted pair cables) against overvoltages and overcurrents imposed on the lines due to nearby lightning flashes.
The procedure is based on the representation of the line by a sequence of sections and nodes, and the evaluation of each node exposure to the lightning-induced surges. Based on the node exposure, the ground flash density and the earth resistivity, the annual number of surges above a given voltage level is calculated. If the voltage level considered is the impulse withstand voltage of the node, then the number of surges above this level corresponds to the annual number of damages to the node. This number shall be multiplied by the loss due to induced surges in order to obtain the risk of failure due to indirect lightning flashes. The highest risk of all nodes is the risk of the line.
The risk of failure due to indirect lightning flashes (R'Z) can be used in the risk assessment of a larger system to which the telecommunication line is a part, according to IEC 62305-2. The calculated risk can also be used by the line owner (e.g., telecommunication operator) in order to evaluate the need of implementing additional protection measures on the line. In this case, the calculated risk (R'Z) shall be compared with the tolerable risk due to indirect flashes (RTi), the latter calculated based on ITU T K.72. If the calculated risk is lower than the tolerable limit, the line is adequately protected. Otherwise, it is necessary to implement additional protection measures until the risk of damage is lower than or equal to the tolerable limit.
The appendices are organized as follows: Appendix I provides data on the electrical characteristics of cable shields, Appendix II presents an algorithm to guide the elaboration of software based on this Recommendation, Appendix III presents the calculation of the collection area for flashes near the line and Appendix IV shows some examples of calculation.
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Citation: |
https://handle.itu.int/11.1002/1000/11630 |
Series title: |
K series: Protection against interference |
Approval date: |
2012-05-29 |
Provisional name: | K.pair |
Approval process: | AAP |
Status: |
In force |
Maintenance responsibility: |
ITU-T Study Group 5 |
Further details: |
Patent statement(s)
Development history
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ITU-T Supplement
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Title
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Status
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Summary
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Table of contents
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Download
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K Suppl. 3 (10/2015)
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ITU-T K.20, K.21, K.45, K.82 – Additional criteria to protect telecommunication cabling during a power cross event
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In force
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here
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here
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here
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K Suppl. 8 (11/2017)
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Resistibility analysis of 5G systems
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In force
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here
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here
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here
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K Suppl. 9 (05/2019)
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5G technology and human exposure to radiofrequency electromagnetic fields
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In force
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here
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here
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here
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K Suppl. 10 (11/2017)
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Analysis of electromagnetic compatibility aspects and definition of requirements for 5G mobile systems
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In force
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here
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here
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here
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K Suppl. 13 (12/2021)
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Radiofrequency electromagnetic field (RF-EMF) exposure levels from mobile and portable devices during different conditions of use
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In force
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here
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here
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here
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K Suppl. 14 (09/2019)
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The impact of RF-EMF exposure limits stricter than the ICNIRP or IEEE guidelines on 4G and 5G mobile network deployment
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In force
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here
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here
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here
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K Suppl. 16 (10/2022)
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Electromagnetic field compliance assessments for 5G wireless networks
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In force
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here
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here
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here
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K Suppl. 19 (09/2019)
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Electromagnetic field (EMF) strength inside underground railway trains
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In force
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here
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here
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here
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K Suppl. 29 (07/2022)
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Electromagnetic field strength inside and outside of electric vehicles using wireless power transfer technology
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In force
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here
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here
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here
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Title |
Approved on |
Download |
Mitigation measures for telecommunication installations – Chapter 10
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2006
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here
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Mitigation measures for telecommunication installations
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2004
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here
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Earthing and bonding
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2003
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here
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Guide to the use of ITU-T Publications produced by Study Group 5 aimed at achieving Electromagnetic Compatibility and Safety
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2002
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here
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The protection of telecommunication lines and equipment against lightning discharges – Chapters 9 and 10
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1995
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here
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The protection of telecommunication lines and equipment against lightning discharges – Chapters 6, 7 and 8
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1978
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here
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Earthing of telecommunication installations
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1976
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here
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