international telecommunication union geneva, 20-21 july 2009 electrical safety and electromagnetic...

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)

InternationalTelecommunicationUnionGeneva, 20-21 July 2009 2

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)


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


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


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


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




Protection & Safety issues : Avoiding DamagesDamages and InjuriesInjuries to people




Damages

Sources of damages:LightningElectric Power and Traction systemsElectrostatic discharge (ESD)

The damages can be reduced by:Equipment resistibilityInstallation rulesProtective measures


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


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


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


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


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


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


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




Protection & Safety issues: Avoiding Damages and Injuries to people




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


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”


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


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




Protection & Safety issues: Avoiding Damages and Injuries to people


Human exposure to EMFs Guidance for the telecommunication sector and support to developing countries (Resolution 72)


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


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)


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


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

international telecommunication union geneva, 20-21 july 2009 electrical safety and electromagnetic...

Documents

telecommunication sector

resistibility slide

equipment protection

damages damages

damages sources of damages

protection levels

equipment damage

equipment operational