international telecommunication union geneva, 20-21 july 2009 electrical safety and electromagnetic...
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InternationalTelecommunicationUnion
Geneva, 20-21 July 2009
Electrical Safety and
Electromagnetic Compatibility
Ahmed ZEDDAM,ITU-T SG 5 Chairman
(France Telecom)
Claude MONEYRapporteur of Q6/5
(Swisscom)
ITU Consultation on Conformance Assessment and Interoperability Testing
(Geneva, 20-21 July 2009)
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Outline of the presentation
ITU-T SG5 mandate and objectives
Protection & Safety issues : Avoiding DamagesDamages and InjuriesInjuries to people
EMC issue : Limiting disturbancesdisturbances to and from telecommunication systems
Human exposure to EMFs GuidanceGuidance for the telecommunication sector and support to developing countriessupport to developing countries (Resolution 72)
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ITU-T SG 5
SG 5 Title:“Environment & Climate Change”
SG 5 Mandate Study Group 5 is responsible for :
Studies related to protection of telecommunication networks and equipment from interference and lightning;
Studies related to electromagnetic compatibility (EMC), safety and health effects connected with electromagnetic health effects connected with electromagnetic fieldsfields produced by telecommunication installations and devices, including cellular phones;
Studies on the existing copper network outside plant and related indoor installations.
Studies on ICT & Climate Change
In this field, ITU-T SG 5 is the most experienced and competent standardization body
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Meaning of the Mandate: ExampleStudy Electromagnetic Phenomena that can potentially cause damages or disturbancesdamages or disturbances to telecommunication installations or injury to people injury to people (telecommunication personnel and service users) as well as health effect health effect to population
MDFSwitchingequipment
Subscriber premises
Remote site
Telecommunication centreLightnin
g
Power line
Telecom line
Mobile phone
Radiostation
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SG 5 structure
WP 1/5(Resistibility)Equipment Resistibility Lightning protectionEarthing & BondingElectromagnetic interference from power and traction systemsSafety
WP 2/5(EMC)
Human exposure to e.m. fieldsEMC
EmissionImmunity
Electromagnetic security
WP 3/5Climate change
ICT & climate changeMethodologyPower feeding systemsEnergy efficiencyEnvironmental protection, recycling
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Objective
Study electromagnetic phenomena to define PROTECTIVE MEASURES and/or INSTALLATION TECHNIQUES by means :
Recommendations: K-seriesRecommendations: K-seriesDirectivesDirectives
HandbooksHandbooks Lightning HandbookEarthing Handbook Measuring HandbookMitigation Handbook
Recommendations for limiting the RISK of:
DamagesDamages to telecommunication installations and equipmentsDisturbancesDisturbances to and from telecommunication systemsInjury to peopleInjury to people
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Outline of the presentation
ITU-T SG5 mandate and objectives
Protection & Safety issues : Avoiding DamagesDamages and InjuriesInjuries to people
EMC issue : Limiting disturbancesdisturbances to and from telecommunication systems
Human exposure to EMFs GuidanceGuidance for the telecommunication sector and support to developing countriessupport to developing countries (Resolution 72)
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Damages
Sources of damages:LightningElectric Power and Traction systemsElectrostatic discharge (ESD)
The damages can be reduced by:Equipment resistibilityInstallation rulesProtective measures
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Resistibility and Protection
Preventing equipment damage may require a combination of resistibilityresistibility and protectionprotection
Resistibility isThe ability of the equipment to withstand an over-voltage or over-current
Protection isThe addition of protective measures to prevent damages from larger surges
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SG 5 role in the equipment protection
SG 5 is unique in over-voltage protection
Defines equipment resistibility requirementsEnsures coordination between equipment and external protectionsEvaluates installation practices and their effect on resistibility
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Equipment resistibility requirements
Customer’s
premisesK.20 K.45 K.21
Telecom
centres
Access Networ
k
K.44Test methods
Equipments have to work in many different operators’ environments. However, there’s a need for a single environment requirement
Relevant RecommendationsTests:
Impulse tests (Lightning) Induction tests at power
frequencies (16, 50 or 60 Hz) Power contact tests
Two protection levels: Basic Enhanced
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Resistibility tests
Conformance testingTesting is performed with the equipment operational and connected to any associated equipment. Testing is performed for each normal mode of operation e.g. “on hook” and “off hook”.Testing is performed
Line to line (transverse)Line to earth (longitudinal)Port to external port (e.g. Telecommunications to mains port)
For all tests, performancecriteria are defined
Damages
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Protection measures
Installation practicesMultiservice Surge Protective Device (MSPD) if required. Depends on risk assessmentEarthing and bondingA new Home Network Special Group has recently been established to investigate damages and provide installation guidelines
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Safety
SG 5 is not the lead working group. This role is held by IEC
However, SG 5 shall be involved whensafety and resistibility are linked e.g. insulation is used as a protection measurethe IEC assumes that the network operator will install protection in lightning prone areasnetwork operators’ special needs have to be taken into account
Relevant RecommendationsK.50, K.51, K.64, K.75
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Example: Recommendation K.57 Protection measures for radio base stations sited
on power line towers
RBS cabinet between the legs of the tower
RBS antenna and the elevated cabinet
Recommendation K.57 (09/2003, Geneva):www.itu.int/rec/T-REC-K/eThe CIGRE Technical Brochure N° 266 www.e-cigre.org
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Outline of the presentation
ITU-T SG5 mandate and objectives
Protection & Safety issues: Avoiding Damages and Injuries to people
EMC issue : Limiting disturbancesdisturbances to and from telecommunication systems
Human exposure to EMFs GuidanceGuidance for the telecommunication sector and support to developing countriessupport to developing countries (Resolution 72)
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Electromagnetic Compatibility
EMC Recommendations of K. series cover:
Definition of environment K.34Equipment test/conformance K.43, K.48, K.49, K.63, K.75Test/conformance of the networkEmission of networks K.60
ITU-T SG5 normally refers to basic documents produced by IEC and develops Recommendations on How to apply them in the Telecom environment
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Example: Recommendation K.63
Maintaining the suitability of production telecommunications equipment to its intended electromagnetic environment
Recommendation K.63 defines rules on how to execute tests on normal production for checking the compliance with the EMC requirements.Stability of the productSupport both operator and manufacturerRec. K.63 suggests that only 3 tests, performed on a small number of equipments selected at random from a batch, are sufficient to give a good confidence on EMC performance:
1.1. Radiated emission Radiated emission 2.2. ESD ESD 3.3. EFT EFT
Classification based on these 3 tests:Class I: Equipment “suitable”Class II: Equipment “Acceptable”Class III: Equipment “Not suitable”
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Radiation: why to deal with?
Risk: reduced revenue if the deployment of broad band services is restricted to some areas due to interference to other services
How does interference occur How to manage this interference problem
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Radiation
Risk: restricted deployment of broad band services due to interference to other “radio” services
How does interference occur How to manage this interference problem
Example: recommendation K.60To be used only in case of radio interferenceGives advice how to solve the interference case: Defines border between network operator and Authority responsibility
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Outline of the presentation
ITU-T SG5 mandate and objectives
Protection & Safety issues: Avoiding Damages and Injuries to people
EMC issue : Limiting disturbancesdisturbances to and from telecommunication systems
Human exposure to EMFs Guidance for the telecommunication sector and support to developing countries (Resolution 72)
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Human exposure to electromagnetic fields (EMF)
Question 3/5: Human exposure to electromagnetic fields (EMF) due to radio systems and mobile equipment
Guidance for the telecommunication sectorCollaboration with other
standardization bodies (IEC, CENELEC, WHO) in order to avoid duplication of workSupport to developing countries –
Resolution 72
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Relevant ITU-T Recommendations on EMF:
K.52 (2000/2004) Guidance on complying with limits for human exposure to electromagnetic fields
K.61 (2003/2008) Guidance to measurement and numerical prediction of electromagnetic fields for compliance with human exposure limits for telecommunication installations
K.70 (2007) Mitigation techniques to limit human exposure to EMF's in the vicinity of radiocommunication base stations
K. guide (under development) Guide to the Management of Human Exposure to Electromagnetic Fields (EMFs)
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Example :Recommendation ITU-T K.70
Mitigation techniques to limit human exposure to EMFs in the vicinity of radiocommunication stations
Modeling of the transmitting antennasImportance of the Vertical Radiation Pattern (VRP)Identification of the main source of radiationMitigation techniques in order to reduce radiation level – if requiredEMF-estimator – software with the library of examples of the transmitting antennas
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Conclusion
Only an incomplete picture of the ITU-T SG5 activities has been presented
SG 5 hasn’t produced recommendations for conformance and interoperability testing. However, resistibility recommendations (K.20, K.21, K.44 and K.45) minimize equipment down time (reduction in damages to equipment from lightning and power induction surges) and might be seen as conformance criteria
Furthermore, minimising downtime could be considered a subset of interoperability.
• The Recommendations dealing with resistibility conformance would be useful to consider for an ITU mark program