ETSI TR 103 229 V1.1.1 (2014-07)

Environmental Engineering (EE); Safety Extra Low Voltage (SELV) DC power supply network for ICT devices with energy storage and grid or renewable energy sources options

DTR/EE-02042

General Information

• Status: Published
• Publication Date: 03-Jul-2014
• Technical Committee: EE 2 - EE Power Supply
• Current Stage: 12 - Completion
• Due Date: 02-Jul-2014
• Completion Date: 04-Jul-2014
• Mandate: M/462

Standards Content (Sample)

ETSI TR 103 229 V1.1.1 (2014-07)






Technical Report
Environmental Engineering (EE);
Safety Extra Low Voltage (SELV) DC power supply network for
ICT devices with energy storage and grid or renewable energy
sources options

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2 ETSI TR 103 229 V1.1.1 (2014-07)



Reference
DTR/EE-02042
Keywords
energy management, power supply, renewable
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3 ETSI TR 103 229 V1.1.1 (2014-07)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 7
3 Abbreviations and symbols . 9
3.1 Symbols . 9
3.2 Abbreviations . 9
4 General architecture of a CPE SELV DC network . 10
4.1 Power distribution efficiency and voltage choice considerations . 12
4.2 Efficiency targets for element of the DC power supply network solution. 13
4.3 Power expendability, modularity and power regulation . 14
4.3.1 Modularity and Power expandability . 14
4.3.2 Transient power regulation . 15
4.3.3 Voltage regulation, ripple, noise, inrush current . 15
4.4 Reliability and maintenance . 16
4.4.1 MTBF . 16
4.4.2 Failure detection and replacement . 16
4.5 SELV plugs discussion . 16
4.6 EMC requirements . 17
4.6.1 EMC emission and immunity . 17
4.6.2 Voltage regulation, ripple, noise, inrush current . 17
4.7 Eco-Environmental specification . 18
4.7.1 Ecodesign . 18
4.7.2 Lifetime . 19
4.7.3 Copper used in distribution and energy efficiency . 19
4.8 Safety aspects . 20
4.9 Control/monitoring aspects . 21
Annex A: Loss and section design for SELV DC network distribution and example . 22
Annex B: Inputs for defining SELV DC network architecture and energy gain assessment
compared to individual adapters . 26
B.1 GGPAH home DC distribution architecture solution . 26
B.2 Emerge Alliance 24 V ceiling distribution specification . 26
B.3 IEEE UPAMD™ P1823™ project . 26
Annex C: Setting solution for DC/DC converter . 27
C.1 UI setting solution . 27
C.2 Cable setting solution . 27
C.2.1 Passive solution example . 27
C.2.2 Digital solution example . 27
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4 ETSI TR 103 229 V1.1.1 (2014-07)
Annex D: Assessment of the benefit of the SELV DC network . 29
Annex E: Bibliography . 30
History . 31

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5 ETSI TR 103 229 V1.1.1 (2014-07)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Environmental Engineering (EE).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "may not", "need", "need not", "will",
"will not", "can" and "cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms
for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
With the massive development and convergence of Telecom and IT, there are more and more customer Premises
Equipment such as ICT devices terminals and home network. Each of them requires an electric adapter and an AC plug
to be powered. That creates a forest of cables and energy losses, so the need of mutualising power at the level of a room
with a SELV DC network has appeared with the benefit of reducing the amount of adapters and plugs, reducing by the
way quantity of material used (plastic, copper, electronic) and thus reducing electronic wastes.
In addition this will allow simpler reuse of the output of this common power supply for new ICT devices by using the
universal power adapters for fixed devices as standardized by ETSI and recommended by ITU-T. There would also be a
significant saving on power consumption from a better efficiency on a wide range of power and reduced no load power
losses.
For each of USB-A charger avoided by connecting a USB-A detachable charging cable to the DC network, it has been
roughly assessed for 1 Billion units, a potential saving of 100 000 tons of power supply material, and 2 TWh
consumption, 1 million tons of CO2 emission each year.
Other benefits are offered to users in the zone or room where the SELV DC networks operate such as autonomy by the
battery and grid energy cost reduction by using renewable energy sources, PV being the easiest to install having a very
long lifetime.
Moreover, it is an enabler and extender of telecom service use in emerging countries where there is no electricity grid
and it brings at the same time some additional electricity for other use such as lighting with LEDs.
Finally, the SELV distribution is the natural extension in rooms of the Building 400 VDC distribution when it will be
widely spread as it seems to be a useful complement to distribution AC to offer more resilience to disaster and improve
efficiency and use of renewable energy at building level in smart cities and micro grids.
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6 ETSI TR 103 229 V1.1.1 (2014-07)
1 Scope
The present document specifies a Safety Extra Low Voltage DC power supply unit for powering at home or in public
area (stores, hotels, railway stations, etc.) any ICT devices equipped with DC input or any ICT adapter with DC input
compliant with EN 300 132-3-1 [i.17].
It gives information on:
• architecture with multi-outputs or DC network and powering area (room, zone);
• input and output voltage interface;
• configuration of interface voltage;
• optimization of efficiency and cost by mutualising several devices on the same DC power system;
• compatibility with future building using the up to 400 VDC power interface defined in EN 300 132-3-1 [i.17];
• integrated power shutdown management, to save energy as much as possible;
• reliability;
• EMC and resistibility;
• power autonomy to enable standalone power of ICT in case of crisis (electric grid failure, climatic crisis,
earthquake, etc.);
• possibility to use renewable energy especially in emerging countries with no grid or of poor quality grid:
which input interface, and how to make the sizing?
• possibility to power devices other than ICT such as low power light which highly increases life quality and
sustainable development;
• some information on product safety;
• ecodesign principles with assessment of gains in mass of material use, energy and CO2 emission.
The present document also gives an overview of other existing standards in the field.
The detailed description of power generators and power converters or controllers are out of the scope.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
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7 ETSI TR 103 229 V1.1.1 (2014-07)
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] Recommendation ITU-T L.1000: "Universal power adapter and charger solution for mobile
terminals and other hand-held ICT devices".
[i.2] Recommendation ITU-T L.1001: "External universal power adapter solutions for stationary
information and communication technology devices".
[i.3] Recommendation ITU-T L.1002 "External universal power adapter solutions for portable
information and communication technology devices".
[i.4] "Code of Conduct on Energy Efficiency of External Power Supplies": European Commission
Directorate-General JRC Joint Research Centre Institute for Energy and Transport Renewable
Energy Unit.
[i.5] ETSI EN 302 099: "Environmental Engineering (EE); Powering of equipment in access network".
[i.6] Recommendation ITU-T K.74: "EMC, resistibility and safety requirements for home network
devices".
[i.7] IEC 61000-3-2: "Electromagnetic compatibility (EMC) -Part 3-2: Limits -Limits for harmonic
current emissions (equipment input current less than or equal to 16 A per phase)".
[i.8] IEC 60038: "IEC standard voltages".
[i.9] IEC 60950-1: "Information technology equipment - Safety - Part 1: General requirements".
[i.10] ETSI EN 300 132-2: "Environmental Engineering (EE); Power supply interface at the input to
telecommunications and datacom (ICT) equipment; Part 2: Operated by -48 V direct current (dc)".
[i.11] IEC 60896 series: "Stationary lead-acid batteries".
[i.12] ETSI ES 202 336 (all parts): "Environmental Engineering (EE); Monitoring and control interface
for infrastructure equipment (Power, Cooling and environment systems used in telecommunication
networks)".
[i.13] IEC 60364-4-41: "Low-voltage electrical installations - Part 4-41: Protection for safety -Protection
against electric shock".
[i.14] IEC 62430: "Environmentally conscious design for electrical and electronic products".
[i.15] ETSI TS 103 199: "Environmental Engineering [EE]; Life Cycle Assessment (LCA) of ICT
equipment, networks and services; General methodology and common requirements".
[i.16] Recommendation ITU-T L.1410: "Environmental impact Assessment method for goods network
and service".
[i.17] ETSI EN 300 132-3-1 (V2.1.1): "Environmental Engineering (EE); Power supply interface at the
input to telecommunications and datacom (ICT) equipment; Part 3: Operated by rectified current
source, alternating current source or direct current source up to 400 V; Sub-part 1: Direct current
source up to 400 V".
[i.18] IEEE UPAMD™ P1823™: "Universal Power Adapter for Mobile Device".
[i.19] IEC TC 100: "Project P1683 of Technical Specification of "Universal charger for PC".
[i.20] Recommendation ITU-T K.66: "Protection of customer premises from overvoltages and
overcurrents".
[i.21] ISO 11898-3: "Road vehicles -- Controller area network (CAN) -- Part 3: Low-speed, fault-
tolerant, medium-dependent interface".
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8 ETSI TR 103 229 V1.1.1 (2014-07)
[i.22] Recommendation ITU-T K.21: "Resistibility of telecommunication equipment installed in
customer premises to overvoltages and overcurrents".
[i.23] EU directive on charger efficiency and no load power Energy Star V2.
[i.24] Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their
Disposal.
[i.25] IEC 60320-1: "Appliance couplers for household and similar general purposes - Part 1: General
requirements".
[i.26] ISO 14040: "Environmental management -- Life cycle assessment -- Principles and framework".
[i.27] ISO 14044: "Environmental management -- Life cycle assessment -- Requirements and
guidelines".
[i.28] "The first thousand optimized solar BTS stations of Orange group, A very positive experience full
of learning", Didier Marquet Orange et alii., IEEE Intelec 2011 Amsterdam.
[i.29] "Spread of DC power in telecom/data centres and homes/offices with renewable energy and
energy autonomy" Didier Marquet (Orange), Toshimitsu Tanaka (NTT-f), Kensuke Murai, Tanaka
Toru, Tadatoshi Babasaki (NTT), IEEE/Intelec 2013 Hamburg.
[i.30] Darnel study, "External AC-DC Power Supplies: Economic Factors, Application Drivers,
Architecture/Packaging Trends, Technology and Regulatory Developments", Tenth Edition, Feb
2011.
[i.31] GSMA 2010: "Green Power for Mobile", Bi-annual Report November 2010.
[i.32] ITU-D: "ICT 2011 development outlook".
[i.33] "New power supply optimiSed for new telecom networks and services Didier Marquet et alii,
France Telecom CNET, Jean-Paul Gabillet et alii ALCATEL-CIT", IEEE Intelec 1999
Copenhagen.
[i.34] Recommendation ITU-T K.85: "Requirements for the mitigation of lightning effects on home
networks installed in customer premises".
[i.35] IEC 62619: "Secondary cells and batteries containing alkaline or other non-acid electrolytes -
Safety requirements for large format secondary lithium cells and batteries for use in industrial
applications".
®
[i.36] Emerge Alliance .
NOTE: Available at: http://www.emergealliance.org/.
[i.37] Green Grid Platform At Home voluntary organization in Japan.
NOTE: Available at http://ggpah.org/.
[i.38] GeSI-ITU-T Study 2012, An Energy-aware Survey on ICT Device Power Supplies.
NOTE: Available at http://www.itu.int/ITU-T/climatechange/report-ict-device.html.
[i.39] CENELEC EN 55022: "Information technology equipment - Radio disturbance characteristics -
Limits and methods of measurement".
[i.40] CENELEC EN 55024: "Information technology equipment - Immunity characteristics - Limits and
methods of measurement".
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9 ETSI TR 103 229 V1.1.1 (2014-07)
3 Abbreviations and symbols
3.1 Symbols
For the purposes of the present document, the following symbols apply:
I current
Pu Useful Power of the load
R resistance
U voltage
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
ASCII American Standard Code for Information Interchange
CAN Controller Area Network
CMOS Complementary Metal Oxyde Semiconductor
CPE Customer Premises Equipment
CPS Common Power Supply
DC Direct Current
DIN Deutsches Institut für Normung
GGPAH Green Grid Platform At Home
GHG Green House Gas
HF High Frequency
ICT Information and communications technology
LCA Life Cycle Assessment
MPPT Maximum Power Point Tracker
MTBF Mean Time Between Failure
NTT Nippon Telegraph and Telecom
PC Personal computer
PoE Power over Ethernet
PSU Power Supply Unit
PV PhotoVoltaïc
PWM Pulse-width modulation
RH Relative Humidity
SCCP Short Chain Chlorinated Paraffins
SELV Safety Extra Low Voltage
UCPS Universal Common Power Supply
UPA Universal Power Adapter.
UPAMD™ Universal Power Adapter for Mobile Devices
VAC Volt in Alternating Current
VDC Volt in Direct Current
XML eXtended Mark-up Language
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10 ETSI TR 103 229 V1.1.1 (2014-07)
4 General architecture of a CPE SELV DC network
Many studies are showing the extension of the use of ICT terminals in Customer Premises all over the world. For
example the ITU-D outlook [i.32] is showing that Telecom network and terminals are developing in Emerging countries
faster than the electric grid.
For the mobile network a GSMA study [i.31] and for example an IEEE/intelec 2011 paper [i.28] have shown that the
massive deployment would be more based on renewable energy and single legacy Diesel generator could be replaced by
hybrid power system. As a consequence of this fast Telecom network development, there is an increased need of
electricity in customer premises, that can bring at the same time more comfort and social benefit, such as low power
consumption lighting for emerging countries. The universal adapter solution already promoted for powering ICT
devices Recommendation ITU-T L.1000 [i.1], Recommendation ITU-T L.1001 [i.2] or Recommendation ITU-T L.1002
[i.3] ensures the compatibility with renewable energy systems such as those based on PV modules, either small system
in SELV voltage and these Recommendations introduce compliance of the chargers with EN 300 132-3-1 [i.17] at
building level. IEEE/intelec paper 2013 [i.29] is showing a possible start of wide spread of these solutions.
As in many homes there is not only one terminal but several, and because there is a need of shared charging points for
users (public or private), it appears that a DC network solution could be an optimized solution. It was already stated as
already presumed in IEEE/Intelec 1999 paper [i.33].
Other solutions based on AC inverter using for example DC from solar PV module or battery allow the use of AC
adapter but the efficiency and reliability is poor. Even if the up to 400 VDC interface is possible for complete swap of
the distribution inside buildings but it seems there is also a space for a more optimized and progressive zone or room
lower voltage DC network. The best solution for safety is a SELV voltage lower than 60 VDC in compliance to
IEC 60364-4-41 [i.13]. The DC voltage level, would depend on the environment where it is used (e.g. dry or wet). For
maximal safety, it seems better to keep this limit for wet area not at the maximum value of 120 VDC. 30 VDC limit is
even better for human safety if there is a serious risk of water ingress.
Considering the increasing need of security and availability of ICT, this solution can also in developed countries. Japan
has an initiative on that in greengrid@home [i.37]. There will be compatibility with up to 400 VDC network.
In addition, a SELV DC network mainly for telecom, health and safety ICT can bring at the same time a back-up
possibility for more autonomy and less failure of sensible ICT devices while reducing the use of fossil energy resources
and the CO2 emission and other environmental or human risks.
Figure 1 is presenting the general architecture of a home SELV DC grid able to power home CPE equipment. It can also
be applied in other customer premises: small office, commercial or business building. Not all possible voltage
converters are represented, refer to DC distribution network description list in this clause.
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11 ETSI TR 103 229 V1.1.1 (2014-07)
Other local
Generator
AC or DC Power Grid Wind
PV module
Fuel cell
Energy
Water turbine
storage:
Stirling type
Battery,
Muscular type
Solar Flywheel,
(sport, animals)
Power supply
Controler
…
…
SELV primary DC bus
SELV
Power output management
distribution
network
Star distribution
DC/AC inverter
Option
Sub DC bus
DC/DC
or DC node
device
device
device device device device

NOTE 1: This architecture can include also an optional reverse power feeding module connected to the DC
distribution network compliant with EN 302 099 [i.5].
NOTE 2: DC/DC Converter on sub DC bus or DC nodes are called POL.

Figure 1: Architecture of a SELV DC power system and distribution grid solution in CPE
This architecture takes into account other studies and ongoing standardization:
• Darnel study on charger and power supply, [i.30]
®
• Emerge Alliance 24 V distribution for lighting and ICT device in office or commercial building rooms [i-36]
• ITU-T SG5 L.1000 [i.1], L1001 [i.2], L.1002 [i.3]
• IEEE UPAMD™ P1823™ [i.18]
• IEC TC 100 P1683 [i.19] on universal interface for computers [i.19]
• SELV home power distribution in Japan Green Grid Platform At Home [i.37]
Refer to annex B for more details.
The power generating system includes:
• A primary SELV DC bus where are connected: energy storage, primary power supply using DC or AC grid,
generators and output power distribution management system.
• A SELV DC distribution network feeding power to loads directly or through DC/DC and sub distribution.
NOTE 1: The input liaison of the controller to the external sources (grid, PV, wind generator, etc.) is out of the
scope of this CPE primary distribution.
NOTE 2: The DC grid is compliant with EN 300 132-3-1 [i.17], and should be compliant with future standards for
DC safety and DC plugs under definition by IEC.
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12 ETSI TR 103 229 V1.1.1 (2014-07)
The SELV DC distribution network includes:
• SELV DC power output management including protected outputs against short-circuit and optional limitation
of power or energy consumption.
• Possible DC subdistribution of different types: bus, star.
• Connection nodes.
• Optional Voltage DC/DC adapter or converter that can be dedicated or common to several devices: it can be
floor level converter (e.g. 24/12 V) or final POL converter (e.g. 12/5 V).
• Optional DC/AC inverter for using existing AC adapters of devices.
• Optional DC/DC step-up converter (e.g. 24/300 V) for using existing DC adapters of devices.
• Plugs for detachable power cable towards devices.
NOTE 3: The power output management and the battery management have to share information. They can be
designed as a common unit.
NOTE 4: Due to possibility of DC/DC conversion in this network there can be more than 1 SELV voltage used to
optimize the copper section and voltage drops and losses on the cables.
4.1 Power distribution efficiency and voltage choice
considerations
A detailed study in annex A is showing the relation between the voltage, the power and the cable section and length.
It appears that 5 V is clearly too low a voltage for power higher than 10 W, 12 V or 10 - 15 V range could be
convenient till 100 W for lower distance than 10 meters as it is in small vehicle for DC sub-network allowing reuse of
common accessories manufactured for car.
It should be noticed that 24 V has been chosen for bigger vehicles such as vans, and that manufacturers have considered
higher voltage for high class vehicles equipped with high power comfort equipment. After a long trend to 36 V or 42 V,
the new trend in car industry is 48 V with dual battery 12 V lead-acid for starter, 48 V for other accessories.
In fixed or mobile homes 12 V is already very common for lighting with incandescent bulbs or LED lights and for small
accessories with motors (fans, etc.). For large working zones or office rooms Emerge Alliance [i.36] is promoting 24 V.
A good compromise could be also a voltage range
...