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Question 3/5

Question 3/5 – Interference to telecommunication networks due to power systems and electrified railway systems
(Continuation of Question 9/5)


The electromagnetic interference experienced by telecommunications networks due to power systems and electrified railway systems has been studied by ITU and documented in the nine volumes of the Directives and in a number of Recommendations. There is a need to maintain these documents and to ensure good coordination between them.

This Question impacts climate change issues by ensuring that the adequate resistibility requirements for equipment and protective measures for installations reduce the amount of equipment and installation damage. By reducing damages less fossils fuels are burnt (personnel do not have to drive to a site to repair equipment) and less manufacturing is required (less replacement equipment is needed).

The following Recommendations and Directives, in force at the time of approval of this Question, fall under its responsibility:

  • K.5, K.6, K.7, K.8, K.9, K.13, K.14, K.19, K.26, K.54, K.57, K.68
  • Directives, except Volume VIII.


Study items to be considered include, but are not limited to:

  • Interference caused by power and traction systems to telecommunication systems. (Input to the amendment of the Directives);
  • Interference to telecommunication systems by the emergence of harmonics flowing on power systems. (Input to amendment of Volume V of the Directives);
  • Method for identifying the transfer potential of EPR occurring in HV and/or MV substation through metallic connection or non-metallic conductive coupling with the earthing system or neutral of LV network. (Input to draft K.hvps1 regarding transfer potential);
    NOTE: Magnitude of transferred voltage caused by phase to earth short circuit of MV network with directly earthed neutral and double earth fault of network with not directly earthed neutral have of special importance.
  • Method for identifying the effective earth current and earthing resistance of sub-stations with special view of earthing resistance of MV/LV transformer station relevant to transferred potential in urban area. (Input to draft K.hvps2 regarding earth potential rise);
  • Interference to telecommunication transmission systems other than POTS, e.g. limits for ISDN and xDSL. Transients occurring on LV supply networks as sources of interference to broadband technologies should also be considered (in collaboration with Question H/5, input to new;
  • Managing of the problem of induction into optic fibre cables containing metallic members. e.g. strength members, moisture barrier, screens and tracer tapes etc. (Possible input to Handbook Outside plant technologies for public networks);
  • Maintenance of Recommendation K.57 aiming at the more complete coverage of the existing installations. The Recommendation K.57 is focused on the protection requirements for base station hold by towers of HV lines. However, there is an increasing need in the telecommunication market for operators to install antennas of radio base stations and/or equipment on utility poles such as MV tower and LV poles installed in urban areas.

The following issues need to be addressed that are related to such installations:

  • Installation locations on the utility pole of the RF antennas/equipment and isolation issues;
  • Electromagnetic interference between the power system and the RF system;
  • Increased lightning protection measures;
  • Safety concerns during installation/maintenance.


Tasks include, but are not limited to:

  • A new Recommendation on interference to telecommunications transmission systems other than POTS, e.g. limits for ISDN and xDSL, with special view of the more extensive use of power electronics in the future smart grids;
  • A new Recommendation on transferred EPR (K.hvps1) and earth potential rise (K.hvps2);
  • Revision of Volume V of the Directives with regard to emergence of harmonics on power plant;
  • Maintenance and enhancement of the relevant Recommendations, definitely K 57;
  • Maintenance and enhancement of some other Volumes of the Directives.

NOTE – The revision of the Directives should be done in collaboration with CIGRE and UIC. An up-to-date status of work under this Question is contained in the SG 5 work programme (use URL as shown in the table below).




  • K-series


  • 2, 4, 8, 9 and 12/5

Study Groups:

  • ITU-T SG 15, ITU-D SG 2

International organizations:


Standardization bodies:

  • CENELEC TC 210, TC 106X