Improving the protection of ICT equipment against lightning strikes

lightning-blogInformation and communication technologies (ICTs) pervade almost every aspect of our lives today with innovative devices enabling us to communicate anywhere and at any time. Yet, despite the extraordinary innovation seen in the industry in recent times, ICT devices, home networks and telecommunications equipment have become more vulnerable to the effects of lightning. This is due to more interconnections within the home and their connection to traditionally non-communications devices such as gas and water smart meters. Overvoltages due to lightning strikes to power lines and telecommunications cables can damage ICT equipment and adversely affect the availability and quality of services.

A new international standard aims to protect telecommunications equipment installed in customer premises from the effects of lightning strikes. The standard, Recommendation ITU-T K.98 “Overvoltage Protection Guide for telecommunications equipment installed in a customer premise” reached first-stage approval (‘consent’ in ITU parlance) on 29 July 2014. This standard focuses on ways in which telecommunications equipment installed in customer premises can be protected from damage due to lightning strikes to power and telecommunications lines/cables. It considers the impact of the different types of mains power distribution systems and determines the level of surge current available at customer premises due to direct strikes to these lines/cables.

The standard was produced within the framework of Working Party 1 (Damage prevention and safety) of ITU-T Study Group 5 (Environment and climate change). The standard was developed with the support of Phil Day, a former Chairman of the Working Party, under the leadership of Ahmed Zeddam, the Chairman of the Study Group.

A key conclusion is that that the majority of installations could be protected for some tens of Euros per equipment cluster and, consequently, significantly increase the reliability of service. Protecting telecommunications equipment, within a structure, requires a combination of two main components:

  1. Equipment resistibility. All equipment installed in customer premises has to be compliant with the appropriate resistibility level of Recommendation ITU-T K.21Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents”.
  2. Additional protective measures :
    • Cable routing practices complying with Recommendation ITU‑T K.66Protection of customer premises from overvoltages
    • Earthing and bonding practices complying with Recommendation ITU‑T K.66
    • Installation of Surge Protective Devices (SPD) for overvoltage protection according to Recommendation ITU-T K.66. This includes the use of both Multi-Service Surge Protective Devices (MSPDs) and primary protectors
    • Installation of an external lightning protection system (LPS) in order to achieve direct strike protection of the building.

The new standard details the information needed to protect telecommunications equipment installed in customer premises from damage due to lightning. More information is provided on the levels of surge current available at customer premises for direct strikes to the services more than 200 metres from the customer premises. It shows that it is possible to protect telecommunications equipment in customer premises, using readily available protection elements, against a direct strike to the incoming service (power or telecommunications) providing that the strike point is more than a couple of hundred metres from the customer premises in an urban or denser service area.

In simple terms, a fairly inexpensive Multiservice Surge Protective Device (MSPD) is used to protect equipment clusters. When necessary, additional surge protective devices (primary protection) need to be installed to protect the MSPDs which have been used to protect the equipment clusters. This means that the majority of installations could be efficiently protected by investing only some tens of Euros per equipment cluster.

As ITU-T Study Group 5 is also responsible for the important issue of mitigation of climate change, it is worth mentioning that applying the measures contained in this standard will also contribute to the reduction of greenhouse gas emissions by reducing the amount of servicing, which would limit the intervention of field technicians, refurbishment and waste.

With regard to the global changes taking place in lightning patterns, we have to provide solutions in order to adapt to global climate change and make telecommunications infrastructure more resilient to cope with these extremes.

This international standard will be made available at: http://www.itu.int/ITU-T/recommendations/index_sg.aspx?sg=5

zeddamDr Ahmed Zeddam, PhD in Physics
Dr Zeddam received Doctor of Research degree in electronicsand the Ph.D. degree in electromagnetic both from the University of Lille, France, where he also held the position of assistant Professor of electronics.Since 1982, he has been employed at Research and Development Division of France Telecom in Lannion where he was until 2009 head of a Research and Development Unit dealing with Electromagnetic Compatibility (EMC). He conducted research on Lightning Protection and EMC for broadband systems of communications. He is involved in several Technical Committees of international standardization bodies dealing with Electromagnetic Compatibility (ITU-T, IEC, and CENELEC). Since 2008 he is Senior Standardisation Manager within Orange and he is currently the Chairman of Study Group 5 of ITU-T “Environment and Climatic Change”. He is also involved in Commission E “Electromagnetic Noise and Interference” of International Union of Radio Science (URSI).He was the General Co-chair of IEEE ISPLC 2011.

DayPhil Day, Bachelor of Engineering – Communications
Phil Day joined Telstra Corporation Limited where he was involved in lightning protection activities. He joined Telstra Research Labs in order to conduct overvoltage protection activitie
s which included equipment and cable network resistibility, equipment resistibly compliance testing, network protection from overvoltages, earthing and bonding, equipment damage investigations and solving equipment damage problems. Phil Day joined ITU-T Study Group 5 in December 1996. He acted as Rapporteur of Question 1 (Electromagnetic resistibility of telecommunication equipment) from 1997 to 2000, producing a key result in the revision of the Resistibility Recommendations through the introduction of an enhanced resistibility level and a more effective coordination test.  He continued to act as Rapporteur of Q4 (Resistibility of new types of communication equipment and access networks). He was elected Vice Chairman of SG5 and appointed Chairman of WP 1/5, serving in these positions from 2009 to 2012. As Convenor of Australia’s National Study Group 5 since 1996 he has been effectively coordinating industry inputs to SG5.

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