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International Telecommunication Union Technical Session on Home Networks Geneva, 29/04/2011 ITU-T Study Group 5 Protection against Lightning Phil Day Australia.

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Presentation on theme: "International Telecommunication Union Technical Session on Home Networks Geneva, 29/04/2011 ITU-T Study Group 5 Protection against Lightning Phil Day Australia."— Presentation transcript:

1 International Telecommunication Union Technical Session on Home Networks Geneva, 29/04/2011 ITU-T Study Group 5 Protection against Lightning Phil Day Australia

2 ITU-T Study Group 5 Introduction o This presentation is about the protection of Home Network (HN) equipment and will specifically cover: Protection parts Philosophy of protection Classification of ports Mechanisms of damage Risk Technical Session - Home Networks - Geneva

3 ITU-T Study Group 5 Introduction (cont) Standards Conclusion Technical Session - Home Networks - Geneva

4 ITU-T Study Group 5 Protection parts o Protection of an installation may require a combination of: Lightning protection of the building. Resistibility of equipment. Protection of incoming lines. Earthing and bonding of the installation Technical Session - Home Networks - Geneva

5 ITU-T Study Group 5 Protection parts Technical Session - Home Networks - Geneva equipment a.c. mains SPD metallic water pipe earth electrodes LPS main earthing terminal Telecommunication cable Figure 1 SPD

6 ITU-T Study Group 5 Protection parts o Protection of the building structure: Protection of the building structure, if necessary, is installed according to the IEC series. It includes a Lightning Protection System (LPS) comprising air terminals, downconductors, equipotential bonding conductors and earth terminations Technical Session - Home Networks - Geneva

7 ITU-T Study Group 5 Protection parts o Resistibility requirements are in Recommendation K.21: inherent and coordination requirement for external ports. inherent requirement for internal ports. basic requirement for general use. enhanced requirement for specific reasons Technical Session - Home Networks - Geneva

8 ITU-T Study Group 5 Protection parts Special requirements where earthing and bonding cannot be achieved Technical Session - Home Networks - Geneva

9 ITU-T Study Group 5 Protection parts o Protection of incoming lines and equipment: Installation of primary protection on external lines; mains and external telecommunication or data lines as required. Installation of protection at the equipment as required Technical Session - Home Networks - Geneva

10 ITU-T Study Group 5 Protection parts o Earthing and bonding Earthing is the connection of the earth bar to earth, usually via an installed earth electrode. Bonding is the interconnection of earth electrodes and interconnection of metallic parts to minimise potential differences Technical Session - Home Networks - Geneva

11 ITU-T Study Group 5 Protection parts (cont) SPDs and cable screens are earthed IEC has the possibility of bonding the PE to the structure earth on each floor to reduce loop sizes Technical Session - Home Networks - Geneva

12 ITU-T Study Group 5 Philosophy of Protection o The first method of protection is to install a Multiservice Surge Protective Device (MSPD): These are described in Recommendation K.66 (currently called a Combination Protection Unit (CPU). They provide equipotential bonding of the ports at the equipment Technical Session - Home Networks - Geneva

13 ITU-T Study Group 5 Philosophy of Protection They will protect against surges induced into the services and internal wiring, and against conducted surges let through by the primary SPD Technical Session - Home Networks - Geneva

14 ITU-T Study Group 5 Philosophy of Protection (cont) o Power and telecommunication Network operators may install SPDs in lightning prone areas. o If not, it is recommended that SPDs be installed as required. o These primary SPDs (telecoms and mains) protect MSPDs, secondary protection and the house wiring Technical Session - Home Networks - Geneva

15 ITU-T Study Group 5 Classification of ports o Equipment can have a combination of internal and external ports: External ports are protectable by a GDT on the telecommunications ports and a mains SPD on the mains port. They must comply with a coordination test Technical Session - Home Networks - Geneva

16 ITU-T Study Group 5 Classification of ports Internal ports require a unique SPD designed according to IEC There is no coordination test in K.21. Guidance on classification of ports is given in K.44 and K.75. Incorrect classification may result in damage Technical Session - Home Networks - Geneva

17 ITU-T Study Group 5 Mechanisms of damage o Strike to the structure (S1) may result in damage to external ports (conducted surges) and internal ports (induced surges) o Strike near to the structure (S2) may result in damage to internal ports (induced surges) Technical Session - Home Networks - Geneva

18 ITU-T Study Group 5 Mechanisms of damage (cont) o Strike to the services (S3) may result in damage to external ports (conducted surges) and internal ports (conducted surges). This is the work introduced by NTT. This issue will be studied over the next few months. o Strike near to the services (S4) may result in damage to external ports (induced surges) Technical Session - Home Networks - Geneva

19 ITU-T Study Group 5 Practices which may cause damage o Internal port connected to external cable. o The interconnected pieces of equipment are connected to different un-bonded electrodes Technical Session - Home Networks - Geneva

20 ITU-T Study Group 5 Risk o Risk is covered in some ITU-T documents but not for damage of customer equipment. o Risk is also covered in IEC , but not for damage of customer equipment. o Need to consider loss versus frequency of damage Technical Session - Home Networks - Geneva

21 ITU-T Study Group 5 Risk (cont) o Recommendation K.hnwr will contain the information for performing a risk assessment and also an example risk assessment. o The frequency of damage will be determined Technical Session - Home Networks - Geneva

22 ITU-T Study Group 5 Relevant Standards o The following ITU-T documents are relevant. K.21, K.44, K.66, K.71, K.74, K.75 and K.hnwr o The following IEC documents are relevant IEC , IEC , IEC parts 12, 21 and 22 and IEC series Technical Session - Home Networks - Geneva

23 ITU-T Study Group 5 Conclusion o If we are to prevent damage to HN equipment we need: Adequate resistibility of equipment. Correct classification and use of ports. Good installation practices. Correct earthing and bonding. Protection for external and internal ports as necessary. _________________________________________________ Technical Session - Home Networks - Geneva


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