(Continuation of Question 5/5) Motivation
In recent years, modern society has experienced a high and steady growing
dependency on telecommunications. In this context, the reliability of
telecommunication services has become an issue of high priority. Operators all
over the world are driving efforts in order to assure the reliability of the
entire telecommunication system, from the backbone stations up to the access
network. Therefore, the protection against the dangerous effects produced by
lightning discharges (high currents associated with strong electromagnetic
fields) is a matter of prime concern. It shall also be reminded that lightning
discharges may jeopardize the users of telecommunications services if an
adequate protection is not provided. This question aims to establish
cost-effective engineering procedures in order to allow the telecommunication
operators to achieve the desired reliability in their networks, as well as the
safety of the customers.
Close collaboration is to be maintained with IEC TC 81, as there has been
established a clear boundary on the standards for lightning protection, where SG
5 has got the responsibility for the development of risk assessment and
protection techniques for telecommunications services and the resulting
recommendations should complement the IEC 62305 series.
This Question impacts climate change issues by ensuring that adequate
resistibility requirements for equipment and protective measures for
installations reduce the amount of equipment and installation damages. By
reducing damages less fossil 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 Handbook, in force at the time of approval of
this Question, fall under its responsibility:
- K.25, K.29, K.39, K.40, K.46, K.47, K.56, K.67, K.71, K.72 and Lightning
Handbook.
Question
The purpose of this Question is to produce new or revised Recommendations or
Chapters of the Lightning Handbook regarding the protection of telecommunication
systems against the dangerous effects of lightning discharges.
Study items to be considered include, but are not limited to:
Protection of fixed telecommunications lines, including the lines made of
symmetric conductors, coaxial cables and non-metal-free fibre-optic cables and
give guidance on installation and protection of power supply systems for
telecommunication installations and equipment outside the central office;
- Protection of mobile and wireless systems, in particular radio base stations
which very often have their antennas installed in high structures exposed to
lightning discharges;
- Protection of telecommunication stations that make part of the network’s
backbone and, therefore, require a high reliability;
- Utilization of the data from lighting location system (LP) to optimize the
network protection;
- Protection of users of telecommunications services from the dangerous effects
of lightning discharges, in collaboration with Question 11/5.
Tasks
Tasks include, but are not limited to:
- Revision of Recommendations K.29 considering the results of experiments
carried out using rocket-triggered lightning over buried telecommunications
cables with different protection schemes;
- Revision of Recommendation K.39 and K.40, taking into account the IEC 62305
standards;
- Revision of Recommendation K.67 based on new information available on the
surges due to lightning.
- Revision of Recommendation K.56 regarding new information available from test
sites, where validation of K.56 using a real installation and rocket triggered
lightning is carried out;
- New Recommendation on the protection of installations at the neighborhood of
telecommunication towers;
- New recommendation on the use of the data from lighting location system (LP)
for network protection;
- Possible revision and/or edition of additional chapters of the Handbook
“Protection of telecommunication lines and equipment against lightning
discharges”. Subjects that could be considered are:
- Evaluation of shielding factor and the effect of SPD on telecommunication
lines (rationale for K.46);
- Evaluation of coupling factors for a radio base station struck by lightning
(rationale for K.56);
- Expected overvoltages induced into coaxial cables by direct and indirect
lightning discharges (input to resistibility Recommendations K.20, K.21, K.44
and K.45);
- Maximum length of bonding wires of SPDs and requirements for loops formed by
the wiring, in order to limit the lightning induced surges.
- Revision of Rec. K.71 based on the experience from its use.
An up-to-date status of work under this Question is contained in the SG 5 Work
Program (use URL as shown in the table below).
Relationships
Recommendations:
Questions:
Study Groups:
Standardization bodies:
- IEC TC 81, CENELEC TC 81X, ETSI ERM
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