ETSI ES 203 474 V1.1.1 (2018-03)
Environmental Engineering (EE); Interfacing of renewable energy or distributed power sources to 400 VDC distribution systems powering Information and Communication Technology (ICT) equipment
Environmental Engineering (EE); Interfacing of renewable energy or distributed power sources to 400 VDC distribution systems powering Information and Communication Technology (ICT) equipment
DES/EE-0252
Okoljski inženiring (EE) - Vmesniško povezovanje obnovljivih energijskih ali razpršenih elektroenergijskih virov s 400-voltnimi enosmernimi distribucijskimi sistemi, ki napajajo opremo informacijske in komunikacijske tehnologije (IKT)
Ta dokument opredeljuje medsebojno povezavo električnih inštalacij na mestu uporabe, ki napaja do 400-voltni enosmerni vmesnik, z obnovljivimi energijskimi ali razpršenimi elektroenergijskimi viri na mestu uporabe. Zajeti vidiki so:
• splošne napajalne arhitekture za:
– povezavo obnovljivega energijskega vira na mestu uporabe (PV, vetrni generator, gorivne celice itd.) z elektrarno na mestu uporabe in zlasti z enosmernim napajalnim sistemom (viri na mestu uporabe so nameščeni na stavbah ali v njihovi okolici);
– izmenjavo električne energije v enosmerno nano ali mikro omrežje in iz njega za uporabo in proizvodnjo z mesta uporabe (to vključuje namensko oddaljeno napajalno omrežje, izdelano za dostopovno opremo IKT, vendar tudi enosmerna napajalna omrežja za splošnejše namene);
– pogoje, ki so potrebni za vzdrževanje določene zmogljivosti za največ 400-voltni napajalni sistem:
električna stabilnost;
zanesljivost in vzdrževalnost;
ustrezna napolnjenost akumulatorja in upravljanje;
usklajevanje zaščite pred delovanjem strel;
omejitve elektromagnetne združljivosti in prehodne omejitve;
– specifikacijo ustreznega dimenzioniranja moči, zahteva za nadzorno spremljanje in merjenje napajanja;
– oceno zmogljivosti (varčevanje z energijo v izmeničnem omrežju, zanesljivost, prilagodljivost, vpliv na okolje itd.).
Ta dokument ne zajema:
• dimenzioniranja obnovljive energije;
• vnos napajanja v podedovana izmenična distribucijska omrežja, kar je že zajeto v številnih standardih (npr. IEC);
• nekaterih možnosti pametnega upravljanja porabe energije prek izmenjav z enosmernim nano ali mikro omrežjem.
General Information
Buy Standard
Standards Content (Sample)
ETSI ES 203 474 V1.1.1 (2018-03)
ETSI STANDARD
Environmental Engineering (EE);
Interfacing of renewable energy or distributed
power sources to 400 VDC distribution systems powering
Information and Communication Technology (ICT) equipment
---------------------- Page: 1 ----------------------
2 ETSI ES 203 474 V1.1.1 (2018-03)
Reference
DES/EE-0252
Keywords
power supply, renewable
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE
Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88
Important notice
The present document can be downloaded from:
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Users of the present document should be aware that the document may be subject to revision or change of status.
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No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2018.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.
TM TM
3GPP and LTE are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M logo is protected for the benefit of its Members.
®
GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
---------------------- Page: 2 ----------------------
3 ETSI ES 203 474 V1.1.1 (2018-03)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Architecture of up to 400 VDC power with REN coupling . 10
4.1 Overview . 10
4.2 Local and distant Renewable Energy coupling architecture to sites with up to 400 VDC . 11
5 Conditions required to keep specified performance for the up to 400 V power system . 13
5.1 General introduction . 13
5.2 Electrical Stability . 13
5.2.1 General consideration on REN power injection. 13
5.2.2 DC injection of locally generated REN power . 14
5.2.3 AC injection of REN power . 14
5.3 Reliability, Maintainability, Safety . 14
5.4 Proper battery charge and management . 15
5.4.1 DC injection of REN power . 15
5.4.2 AC injection of REN power . 16
5.4.3 EMC, transient voltage and current surge limitation . 16
5.4.4 Protection of distribution cables and protection coordination . 16
6 Control-monitoring and metering . 17
7 Assessment of performances improvement of up to 400 VDC systems with REN power . 17
7.1 Reliability, efficiency performance assessment . 17
7.2 Operational KPI of REN coupling to sites with up to 400 VDC systems . 17
Annex A (informative): Different possible coupling architectures of REN energy to AC and
DC site powering systems or to nano or micro grid . 18
A.0 General view . 18
A.1 Interconnection of REN on single AC site input . 18
A.2 Interconnection of REN on single and multiple DC distribution . 19
A.3 Interconnection of REN on single or multiple AC distribution frame . 20
A.4 Hybrid interconnection of REN on AC and DC distribution . 22
A.5 Interconnection of REN to DC nano or micro grid . 23
Annex B (informative): Details on coupling solution of REN generator to an up to 400 VDC
system . 25
Annex C (informative): Control/Monitoring consideration for Renewable Energy system
connexion to AC and DC points in DC systems . 26
Annex D (informative): General consideration for sizing and power coupling of REN system
to up to 400 VDC systems . 28
ETSI
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4 ETSI ES 203 474 V1.1.1 (2018-03)
D.1 General conditions impacting on the REN sizing and power coupling . 28
D.2 Monosource system . 28
D.3 Multisources management and balance between power sources and backup batteries . 29
History . 30
ETSI
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5 ETSI ES 203 474 V1.1.1 (2018-03)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Environmental Engineering (EE).
The up to 400 VDC power solutions feeding the power interface to ICT equipment as defined by ITU-T
(Recommendation ITU-T L.1200 series [1], [2], [3], [i.1], [i.3]) and ETSI [8], are well adapted to straight forward use
of renewable energy or distributed power sources through new simple DC nano or micro grids. This series defines the
coupling of local or remote renewable energy into an up to 400 VDC power system without reducing DC performances
defined in Recommendation ITU-T L.1202 [2] mainly for efficiency and reliability. The main advantages are saving of
fossil fuel (as a source of primary energy consumption), reduction of GHG emission and increase of resilience.
Additional site interconnection by DC grid can even bring more optimization. One other big benefit is that compared to
AC, on 400 VDC there is no synchronization required between the various inputs, which keeps the architecture simple.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "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
The up to 400 VDC power feeding solution for ICT sites (datacenters, telecom centers) and other building using the up
to 400 VDC power interface Recommendation ITU-T L.1200 [1], are well adapted to straightforward use of renewable
energy or distributed power sources through new DC nano or micro grid, most of them being more complex in AC than
in DC. The DC would allow great simplification by avoiding frequency and phase synchronization of AC generators or
inverters.
ETSI
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6 ETSI ES 203 474 V1.1.1 (2018-03)
The present document aims at defining interface and architecture for injecting renewable energy into an up to 400 VDC
power system in charge of providing power to ICT and facilities equipment with an interface compliant to
Recommendation ITU-T L.1200 [1], and with a DC power architecture as defined in Recommendation
ITU-T L.1204 [i.3], without reducing DC performances defined in Recommendation ITU-T L.1202 [2] mainly for
efficiency and reliability.
The addition of local renewable energy will reduce energy consumption from the public utility, and possibly fossil
primary energy consumption and the corresponding high GHG emission.
It can also provide more resilience in case of public electric grid interruption.
In addition, energy exchange is simple with distributed green power sources e.g. photovoltaic, wind power, fuel cell
(FC) or engine generator using green fuel through a DC nano or micro grids at the level of a multi-building site or
between different sites. These sites can be any type of ICT sites such as network access or nodes, data-centers, customer
premises including IoT devices, etc.). Such an inter-buildings or sites power interconnection is called "site grid" by
opposition to public electric utility.
These DC energy exchanges through site grid can bring higher level of optimization such as:
• exploit green-energy sources more efficiently by optimal location of renewable energy generator (e.g. for wind
system in windy places and for PV system, in places out of shadow);
• complement local back-up power system e.g. battery;
• share local renewable energy excess of one site with other sites;
• ensure remote powering of distributed ICT site in the neighbourhood (e.g. by dedicated remote DC power
cables or hybrid optical and DC power cables).
Injection of the renewable energy into the legacy AC public utility should consider the use of electricity for ICT
services, and avoids undetermined use in the neighbourhood that can be inefficient. Key performance indicators could
be used for reducing inconsidered use by accounting for efficient use of renewable energy on one ICT site or
interconnected sites through a nano grid.
Many documents provided in bibliography are elaborating on the benefit and the need of coupling REN energy to local
installation or to nano grid [i.7], [i.14] to ICT installation and the advantages of doing it in DC [i.8], [i.9], [i.10], [i.11],
[i.12]. LCA approach is more detailed in [i.13].
The present document was developed jointly by ETSI TC EE and ITU-T Study Group 5 and published respectively by
ITU and ETSI as Recommendation ITU-T L.1205 [i.1] and ETSI ES 203 474 (the present document), which are
technically equivalent.
ETSI
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7 ETSI ES 203 474 V1.1.1 (2018-03)
1 Scope
The present document defines interconnection of site power installation feeding up to 400 VDC interface, to site
renewable energy or to distributed DC power. The covered aspects are:
• general power architectures for:
- connection of a site renewable energy source (PV, wind generator, fuel cells, etc.) to a site power plant
and especially the DC power system, (the site sources being on the buildings or around);
- exchange of power to and from a DC nano or micro grid for use and production out of the site (this
includes dedicated remote powering network built for ICT access equipment but also more general
purpose DC electric grids);
- conditions required to keep specified performance for the up to 400V power system:
electrical stability;
reliability and maintainability;
proper battery charge and management;
lightning protection coordination;
EMC and transient limits;
- specification of proper power sizing, Requirement for control-monitoring and power metering;
- assessment of performances (AC grid energy saving, reliability, flexibility, environmental impact, etc.).
The present document does not cover:
• renewable energy dimensioning;
• power injection into the legacy AC utilities which is already covered by many standards (e.g. from IEC);
• some of the smart power management possibilities through exchanges with DC nano or micro grid.
2 References
2.1 Normative 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
https://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.
The following referenced documents are necessary for the application of the present document.
[1] Recommendation ITU-T L.1200 (2012): "Direct current power feeding interface up to 400 V at the
input to telecommunication and ICT equipment".
[2] Recommendation ITU-T L.1202 (2015): "Methodologies for evaluating the performance of up to
400 VDC power feeding system and its environmental impact".
[3] Recommendation ITU-T L.1203 (2016): "Colour and marking identification of up to 400 VDC
power distribution for information and communication technology systems".
ETSI
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8 ETSI ES 203 474 V1.1.1 (2018-03)
[4] ETSI EN 301 605 (V1.1.1): "Environmental Engineering (EE); Earthing and bonding of 400 VDC
data and telecom (ICT) equipment".
[5] ETSI ES 202 336 (all parts): "Environmental Engineering (EE); Monitoring and Control Interface
for Infrastructure Equipment (Power, Cooling and Building Environment Systems used in
Telecommunication Networks)".
[6] IEC 60364 series: "Low-voltage electrical installations".
NOTE: Available at https://webstore.iec.ch/searchform&q=IEC%2060364.
[7] IEC 62368-1: "Audio/video, information and communication technology equipment - Part 1:
Safety requirements".
[8] ETSI ES 203 408 (V1.1.1) (2016-12): "Environmental Engineering (EE); Colour and marking of
DC cable and connecting devices".
2.2 Informative 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.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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.1205 (October 2016): "Interfacing of renewable energy or distributed
power sources to up to 400 VDC power feeding systems".
[i.2] ETSI EN 302 099 (V2.1.1): "Environmental Engineering (EE); Powering of equipment in access
network".
[i.3] Recommendation ITU-T L.1204 (2016): "Extended architecture of power feeding systems of up to
400 VDC".
[i.4] Recommendation ITU-T L.1302 (2015): "Assessment of energy efficiency on infrastructure in
data centres and telecom centres".
[i.5] Recommendation ITU-T L.1350 (2016): "Energy efficiency metric of base station site".
[i.6] Recommendation ITU-T L.1410: "Methodology for environmental life cycle assessments of
information and communication technology goods, networks and services".
[i.7] K.K. Nguyen et al. (Projet GreenStar) (2011): "Renewable Energy Provisioning for ICT Services
in a Future Internet" Future Internet Assembly, LNCS 6656 (open access at SpringerLink.com),
pp. 421-431.
[i.8] IEEE/Intelec 2013 (Hamburg): "DC power wide spread in Telecom/Datacenter and in home/office
with renewable energy and energy autonomy", Didier Marquet and al. Orange Labs; Toshimitsu
Tanaka et al. NTT.
[i.9] Vicor White paper: "High-voltage DC distribution is key to increased system efficiency and
renewable-energy opportunities", Stephen Oliver.
NOTE: Available at http://www.vicorpower.com/documents/whitepapers/wp-High-voltage-DC-Distribution.pdf.
[i.10] STARLINE: "Phasing Out Alternating Current Directory: An Engineering Review of DC Power
for Data Centers", David E. Geary.
ETSI
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9 ETSI ES 203 474 V1.1.1 (2018-03)
[i.11] 400 VDC Power Solutions from Emerson Network Power: "Innovative Power Architecture for
Data Center and Telecommunications Sites".
NOTE: Available at https://www.vertivco.com/globalassets/products/critical-power/dc-power-systems/400v-dc-
power-solutions-brochure.pdf.
[i.12] IEEE/Intelec 2014 (paper quoted on Emerge Alliance): "Three Case Studies of Commercial
Deployment of 400V DC Data and Telecom Centers in the EMEA Region", Sara Maly Lisy,
Mirna Smrekar Emerson Network Power.
NOTE: Available at http://www.emergealliance.org/portals/0/documents/events/intelec/TS01-2.pdf.
[i.13] IREED 2011 (Lille 23-24 March 2011, 7 p): "Wiring design based on Global Energy Requirement
criteria: a first step towards an eco-designed DC distribution scheme", C. Jaouen, B. Multon,
F. Barruel.
[i.14] Micro grids: "A bright future".
NOTE: Available at http://www1.huawei.com/enapp/198/hw-110948.htm.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
back-up power system: power system providing energy to equipment of an ICT site in case of downstream electric
unavailability
distributed power source: local electrical power source where energy is produced close to the user and distributed by a
nano or micro grid by opposition to a centralized power plant with a long distance electricity transport grid
NOTE: This local power source can be an individual user power system or a small collective energy power plant
for a group of customers. It can include energy sources or storage or cogeneration of heat and electricity
using any primary energy renewable or not.
distributed power system: system of distributed power source and possibly other function such as energy conversion,
interconnection, safety system, energy storage and corresponding management
ICT equipment (Recommendation ITU-T L.1200 [1]): information and communication equipment (e.g. switch,
transmitter, router, server, and peripheral devices) used in telecommunication centres, data-centres and customer
premises
Interface P (Recommendation ITU-T L.1200 [1]): interface, physical point, at which power supply is connected in
order to operate the ICT equipment
nano grid, micro grid: local area grid connecting some building together at relatively short distance
NOTE: It can be in AC or DC. In general nano grid is lower than 100 kW, micro grid can be of higher power.
"Nano or micro grid" will be used in the present document.
renewable energy: energy which can be obtained from natural resources that can be constantly replenished
NOTE: Source: Australian Renewable energy Agency.
renewable energy source: source producing electrical energy from renewable energy
site grid: DC nano or micro grid between ICT sites by opposition to public electric utility
ETSI
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10 ETSI ES 203 474 V1.1.1 (2018-03)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
BMS Battery Management System
CHP Combined Heat and Power
CT Current Transducer
CU Control Unit
DC Direct Current
EE Energy Efficiency
EMC Electro-Magnetic Compatibility EMC
FC Fuel Cell
GHG Green House Gas
HV High Voltage
HVAC High Voltage AC
ICT Information and Communication Technology
IoT Internet of Things
KPI Key Performance Indicator
LCA Life Cycle Analysis
LVAC Low Voltage AC
LVDC Low Voltage DC
MW Megawatt
PDF Power Distribution Frame
PDU power Distribution Unit
Ppeak Peak power
Pu Used power
PV Photovoltaic
PWM Pulse Width Modulation
REN Renewable Energy
RF Rectifier Function
TCO Total Cost Ownership
VDC Volt DC
4 Architecture of up to 400 VDC power with REN
coupling
4.1 Overview
In existing buildings, AC grid (HVAC or LVAC) and LVAC distributions are powering ICT equipment, cooling
systems, back-up power systems, control/monitoring, lighting, office computers, Ethernet switches routers and many
other equipment in the building such as ventilation, heater, lifts, etc. A part of the equipment is DC powered by the DC
power feeding systems, and this part is mainly using 400 VDC rather than -48 VDC because of the higher power
density of equipment in order to reduce cable cross-section area and distribution losses.
ICT sectors work on the reduction of the non- renewable primary energy use by reducing direct electricity consumption
and producing more Renewable Energy (REN).
The REN generators are generally in LVDC and so power arrangement up to 400 VDC power systems is much more
convenient for injecting REN.
NOTE: REN generators that are in AC are generally producing variable frequency and voltage requiring precise
synchronization for connection to AC grid.
DC REN generators allow easier consumption of locally generated energy or generated by a group of close sites
through DC nano or micro grid compared to solution with local AC generator synchronized with AC grid.
ETSI
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11 ETSI ES 203 474 V1.1.1 (2018-03)
Due to the wide use of AC in ICT buildings, the REN coupling solutions should consider a progressive swap from AC
injection to DC. Figure 1 gives the general principle of energy flow of the renewable energy or distributed DC power to
the existing power system of the building integrating an up to 400 VDC system.
LVAC
AC Board
HVAC
Rectifier/charger
grid up to 400VDC
∼
DC loads
=
AC back-up
Generator AC ICT, cooling,
other AC use Battery
(48V system, UPS)
AC
Generators using Renewable Energy sources, e.g.
DC bidirectional
Sun PV, wind turbine, water flow, green fuel (engine or fuel
DC nano grid
cell)
external
and/or interconnexion interface to DC nano/micro grid
to the building
Figure 1: General energy flow principle for coupling renewable or
distributed DC site grid to an up to 400 VDC power system in a building of a site
The flow direction is indicated by the arrow and reverse direction from REN to grid depends on excess of power not
used by the sites for powering ICT equipment, cooling and air conditioning equipment and building use could be sent to
the AC or DC grids. This is to avoid loss of productivity and to contribute to the local or regional nation electric mix
and CO reduction effort and to obtain a better TCO for the user.
2
Combined Heat and Power generation (CHP) and storage can be also alternatives, but they are not covered in the
present document focused on injection of electricity in DC and partly in AC.
4.2 Local and distant Renewable Energy coupling architecture
to sites with up to 400 VDC
There are different architectures for interconnections of local REN or distributed power systems or DC nano and micro
grid up to 400 VDC power systems in buildings or sites. It includes local renewable power sources:
• connected to AC and/or DC distribution:
- for local consumption;
- for local injection of excess of production into external grid;
• connected to an external DC nano or micro grid:
- for injection of excess of DC production towards other buildings or sites;
- for remote interconnection to the AC grid e.g. for mutualized injection of DC energy excess on one
single point;
- for islanding the group of sites when running on own distributed power production capacity (e.g. pure or
hybrid renewable energy source with energy storage).
ETSI
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12 ETSI ES 203 474 V1.1.1 (2018-03)
NOTE: The connection to DC nano or micro grid for different services is not fully covered in the present
document as R&D is still on-going in many directions such as swapping part of the AC grid power
systems to more energy coming from local renewable energy or from external DC nano or micro grid,
extending resilience of the site to face grid power interruption, taking advantage of smart grid services at
the level of the interconnection to AC grid e.g. renewable energy injection or storage to support the grid,
on demand peak shedding, etc.
Figure 2 gives the general principles of electrical coupling interconnection of the local REN or from DC from
nano/micro grid to the existing power systems of the building integrating up to 400 VDC systems. The power injection
can be done:
• in DC only;
• in AC only;
• in AC and DC.
DC outputs
Main LVAC
Power Distribution
Distribution
Frame (PDF)
Board
HV or LV
Rectifier/charger
DC ICT
AC grid
∼
or other
=
DC use
AC ICT
AC back-up
ITU-T L.1200
Generator
or EN 300 132-3-1
Cooling
Battery
up to 400 V
...
Final draft ETSI ES 203 474 V1.1.0 (2018-01)
ETSI STANDARD
Environmental Engineering (EE);
Interfacing of renewable energy or distributed
power sources to 400 VDC distribution systems powering
Information and Communication Technology (ICT) equipment
---------------------- Page: 1 ----------------------
2 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
Reference
DES/EE-0252
Keywords
power supply, renewable
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE
Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88
Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the
print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2018.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are trademarks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
oneM2M logo is protected for the benefit of its Members.
GSM® and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
---------------------- Page: 2 ----------------------
3 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Architecture of up to 400 VDC power with REN coupling . 10
4.1 Overview . 10
4.2 Local and distant Renewable Energy coupling architecture to sites with up to 400 VDC . 11
5 Conditions required to keep specified performance for the up to 400V power system . 13
5.1 General introduction . 13
5.2 Electrical Stability . 13
5.2.1 General consideration on REN power injection. 13
5.2.2 DC injection of locally generated REN power . 14
5.2.3 AC injection of REN power . 14
5.3 Reliability, Maintainability, Safety . 14
5.4 Proper battery charge and management . 15
5.4.1 DC injection of REN power . 15
5.4.2 AC injection of REN power . 16
5.4.3 EMC, transient voltage and current surge limitation . 16
5.4.4 Protection of distribution cables and protection coordination . 16
6 Control-monitoring and metering . 17
7 Assessment of performances improvement of up to 400 VDC systems with REN power . 17
7.1 Reliability, efficiency performance assessment . 17
7.2 Operational KPI of REN coupling to sites with up to 400 VDC systems . 17
Annex A (informative): Different possible coupling architectures of REN energy to AC and
DC site powering systems or to nano or micro grid . 18
A.0 General view . 18
A.1 Interconnection of REN on single AC site input . 18
A.2 Interconnection of REN on single and multiple DC distribution . 19
A.3 Interconnection of REN on single or multiple AC distribution frame . 20
A.4 Hybrid interconnection of REN on AC and DC distribution . 22
A.5 Interconnection of REN to DC nano or micro grid . 23
Annex B (informative): Details on coupling solution of REN generator to an up to 400 VDC
system . 25
Annex C (informative): Control/Monitoring consideration for Renewable Energy system
connexion to AC and DC points in DC systems . 26
ETSI
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4 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
Annex D (informative): General consideration for sizing and power coupling of REN system
to up to 400 VDC systems . 28
D.1 General conditions impacting on the REN sizing and power coupling . 28
D.2 Monosource system . 28
D.3 Multisources management and balance between power sources and backup batteries . 29
History . 30
ETSI
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5 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
Intellectual Property Rights
Essential patents
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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This final draft ETSI Standard (ES) has been produced by ETSI Technical Committee Environmental Engineering (EE),
and is now submitted for the ETSI standards Membership Approval Procedure.
The up to 400 VDC power solutions feeding the power interface to ICT equipment as defined by ITU-T
(Recommendation ITU-T L.1200 series [1], [2], [3], [i.1], [i.3]) and ETSI [8], are well adapted to straight forward use
of renewable energy or distributed power sources through new simple DC nano or micro grids. This series defines the
coupling of local or remote renewable energy into an up to 400 VDC power system without reducing DC performances
defined in Recommendation ITU-T L.1202 [2] mainly for efficiency and reliability. The main advantages are saving of
fossil fuel (as a source of primary energy consumption), reduction of GHG emission and increase of resilience.
Additional site interconnection by DC grid can even bring more optimization. One other big benefit is that compared to
AC, on 400 VDC there is no synchronization required between the various inputs, which keeps the architecture simple.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "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
The up to 400 VDC power feeding solution for ICT sites (datacenters, telecom centers) and other building using the up
to 400 VDC power interface Recommendation ITU-T L.1200 [1], are well adapted to straightforward use of renewable
energy or distributed power sources through new DC nano or micro grid, most of them being more complex in AC than
in DC. The DC would allow great simplification by avoiding frequency and phase synchronization of AC generators or
inverters.
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6 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
The present document aims at defining interface and architecture for injecting renewable energy into an up to 400 VDC
power system in charge of providing power to ICT and facilities equipment with an interface compliant to
Recommendation ITU-T L.1200 [1], and with a DC power architecture as defined in Recommendation
ITU-T L.1204 [i.3], without reducing DC performances defined in Recommendation ITU-T L.1202 [2] mainly for
efficiency and reliability.
The addition of local renewable energy will reduce energy consumption from the public utility, and possibly fossil
primary energy consumption and the corresponding high GHG emission.
It can also provide more resilience in case of public electric grid interruption.
In addition, energy exchange is simple with distributed green power sources e.g. photovoltaic, wind power, fuel cell
(FC) or engine generator using green fuel through a DC nano or micro grids at the level of a multi-building site or
between different sites. These sites can be any type of ICT sites such as network access or nodes, data-centers, customer
premises including IoT devices, etc.). Such an inter-buildings or sites power interconnection is called "site grid" by
opposition to public electric utility.
These DC energy exchanges through site grid can bring higher level of optimization such as:
• exploit green-energy sources more efficiently by optimal location of renewable energy generator (e.g. for wind
system in windy places and for PV system, in places out of shadow);
• complement local back-up power system e.g. battery;
• share local renewable energy excess of one site with other sites;
• ensure remote powering of distributed ICT site in the neighbourhood (e.g. by dedicated remote DC power
cables or hybrid optical and DC power cables).
Injection of the renewable energy into the legacy AC public utility should consider the use of electricity for ICT
services, and avoids undetermined use in the neighbourhood that can be inefficient. Key performance indicators could
be used for reducing inconsidered use by accounting for efficient use of renewable energy on one ICT site or
interconnected sites through a nano grid.
Many documents provided in bibliography are elaborating on the benefit and the need of coupling REN energy to local
installation or to nano grid [i.7], [i.14] to ICT installation and the advantages of doing it in DC [i.8], [i.9], [i.10], [i.11],
[i.12]. LCA approach is more detailed in [i.13].
The present document was developed jointly by ETSI TC EE and ITU-T Study Group 5 and published respectively by
ITU and ETSI as Recommendation ITU-T L.1205 [i.1] and ETSI ES 203 474 (the present document), which are
technically equivalent.
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7 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
1 Scope
The present document defines interconnection of site power installation feeding up to 400 VDC interface, to site
renewable energy or to distributed DC power. The covered aspects are:
• general power architectures for:
- connection of a site renewable energy source (PV, wind generator, fuel cells, etc.) to a site power plant
and especially the DC power system, (the site sources being on the buildings or around);
- exchange of power to and from a DC nano or micro grid for use and production out of the site (this
includes dedicated remote powering network built for ICT access equipment but also more general
purpose DC electric grids);
- conditions required to keep specified performance for the up to 400V power system:
electrical stability;
reliability and maintainability;
proper battery charge and management;
lightning protection coordination;
EMC and transient limits;
- specification of proper power sizing, Requirement for control-monitoring and power metering;
- assessment of performances (AC grid energy saving, reliability, flexibility, environmental impact, etc.).
The present document does not cover:
• renewable energy dimensioning;
• power injection into the legacy AC utilities which is already covered by many standards (e.g. from IEC);
• some of the smart power management possibilities through exchanges with DC nano or micro grid.
2 References
2.1 Normative 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
https://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.
The following referenced documents are necessary for the application of the present document.
[1] Recommendation ITU-T L.1200 (2012): "Direct current power feeding interface up to 400 V at the
input to telecommunication and ICT equipment".
[2] Recommendation ITU-T L.1202 (2015): "Methodologies for evaluating the performance of up to
400 VDC power feeding system and its environmental impact".
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8 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
[3] Recommendation ITU-T L.1203 (2016): "Colour and marking identification of up to 400 VDC
power distribution for information and communication technology systems".
[4] ETSI EN 301 605 (V1.1.1): "Environmental Engineering (EE); Earthing and bonding of 400 VDC
data and telecom (ICT) equipment".
[5] ETSI ES 202 336 (all parts): "Environmental Engineering (EE); Monitoring and Control Interface
for Infrastructure Equipment (Power, Cooling and Building Environment Systems used in
Telecommunication Networks)".
[6] IEC 60364 series: "Low-voltage electrical installations".
NOTE: Available at https://webstore.iec.ch/searchform&q=IEC%2060364.
[7] IEC 62368-1: "Audio/video, information and communication technology equipment - Part 1:
Safety requirements".
[8] ETSI ES 203 408 (V1.1.1) (2016-12): "Environmental Engineering (EE); Colour and marking of
DC cable and connecting devices".
2.2 Informative 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.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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.1205 (October 2016): "Interfacing of renewable energy or distributed
power sources to up to 400 VDC power feeding systems".
[i.2] ETSI EN 302 099 (V2.1.1): "Environmental Engineering (EE); Powering of equipment in access
network".
[i.3] Recommendation ITU-T L.1204 (2016): "Extended architecture of power feeding systems of up to
400 VDC".
[i.4] Recommendation ITU-T L.1302 (2015): "Assessment of energy efficiency on infrastructure in
data centres and telecom centres".
[i.5] Recommendation ITU-T L.1350 (2016): "Energy efficiency metric of base station site".
[i.6] Recommendation ITU-T L.1410: "Methodology for environmental life cycle assessments of
information and communication technology goods, networks and services".
[i.7] K.K. Nguyen et al. (Projet GreenStar) (2011): "Renewable Energy Provisioning for ICT Services
in a Future Internet" Future Internet Assembly, LNCS 6656 (open access at SpringerLink.com),
pp. 421-431.
[i.8] IEEE/Intelec 2013 (Hamburg): "DC power wide spread in Telecom/Datacenter and in home/office
with renewable energy and energy autonomy", Didier Marquet and al. Orange Labs; Toshimitsu
Tanaka et al. NTT.
[i.9] Vicor White paper: "High-voltage DC distribution is key to increased system efficiency and
renewable-energy opportunities", Stephen Oliver.
NOTE: Available at http://www.vicorpower.com/documents/whitepapers/wp-High-voltage-DC-Distribution.pdf.
[i.10] STARLINE: "Phasing Out Alternating Current Directory: An Engineering Review of DC Power
for Data Centers", David E. Geary.
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9 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
[i.11] 400 VDC Power Solutions from Emerson Network Power: "Innovative Power Architecture for
Data Center and Telecommunications Sites".
NOTE: Available at https://www.vertivco.com/globalassets/products/critical-power/dc-power-systems/400v-dc-
power-solutions-brochure.pdf.
[i.12] IEEE/Intelec 2014 (paper quoted on Emerge Alliance): "Three Case Studies of Commercial
Deployment of 400V DC Data and Telecom Centers in the EMEA Region", Sara Maly Lisy,
Mirna Smrekar Emerson Network Power.
NOTE: Available at http://www.emergealliance.org/portals/0/documents/events/intelec/TS01-2.pdf.
[i.13] IREED 2011 (Lille 23-24 March 2011, 7 p): "Wiring design based on Global Energy Requirement
criteria: a first step towards an eco-designed DC distribution scheme", C. Jaouen, B. Multon,
F. Barruel.
[i.14] Micro grids: "A bright future".
NOTE: Available at http://www1.huawei.com/enapp/198/hw-110948.htm.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
back-up power system: power system providing energy to equipment of an ICT site in case of downstream electric
unavailability
distributed power source: local electrical power source where energy is produced close to the user and distributed by a
nano or micro grid by opposition to a centralized power plant with a long distance electricity transport grid
NOTE: This local power source can be an individual user power system or a small collective energy power plant
for a group of customers. It can include energy sources or storage or cogeneration of heat and electricity
using any primary energy renewable or not.
distributed power system: system of distributed power source and possibly other function such as energy conversion,
interconnection, safety system, energy storage and corresponding management
ICT equipment (Recommendation ITU-T L.1200 [1]): information and communication equipment (e.g. switch,
transmitter, router, server, and peripheral devices) used in telecommunication centres, data-centres and customer
premises
Interface P (Recommendation ITU-T L.1200 [1]): interface, physical point, at which power supply is connected in
order to operate the ICT equipment
nano grid, micro grid: local area grid connecting some building together at relatively short distance
NOTE: It can be in AC or DC. In general nano grid is lower than 100 kW, micro grid can be of higher power.
"Nano or micro grid" will be used in the present document.
renewable energy: energy which can be obtained from natural resources that can be constantly replenished
NOTE: Source: Australian Renewable energy Agency.
renewable energy source: source producing electrical energy from renewable energy
site grid: DC nano or micro grid between ICT sites by opposition to public electric utility
ETSI
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10 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
BMS Battery Management System
CHP Combined Heat and Power
CT Current Transducer
CU Control Unit
DC Direct Current
EE Energy Efficiency
EMC Electro-Magnetic Compatibility EMC
FC Fuel Cell
GHG Green House Gas
HV High Voltage
HVAC High Voltage AC
ICT Information and Communication Technology
IoT Internet of Things
KPI Key Performance Indicator
LCA Life Cycle Analysis
LVAC Low Voltage AC
LVDC Low Voltage DC
MW Megawatt
PDF Power Distribution Frame
PDU power Distribution Unit
Ppeak Peak power
Pu Used power
PV Photovoltaic
PWM Pulse Width Modulation
REN Renewable Energy
RF Rectifier Function
TCO Total Cost Ownership
VDC Volt DC
4 Architecture of up to 400 VDC power with REN
coupling
4.1 Overview
In existing buildings, AC grid (HVAC or LVAC) and LVAC distributions are powering ICT equipment, cooling
systems, back-up power systems, control/monitoring, lighting, office computers, Ethernet switches routers and many
other equipment in the building such as ventilation, heater, lifts, etc. A part of the equipment is DC powered by the DC
power feeding systems, and this part is mainly using 400 VDC rather than -48 VDC because of the higher power
density of equipment in order to reduce cable cross-section area and distribution losses.
ICT sectors work on the reduction of the non- renewable primary energy use by reducing direct electricity consumption
and producing more Renewable Energy (REN).
The REN generators are generally in LVDC and so power arrangement up to 400 VDC power systems is much more
convenient for injecting REN.
NOTE: REN generators that are in AC are generally producing variable frequency and voltage requiring precise
synchronization for connection to AC grid.
DC REN generators allow easier consumption of locally generated energy or generated by a group of close sites
through DC nano or micro grid compared to solution with local AC generator synchronized with AC grid.
ETSI
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11 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
Due to the wide use of AC in ICT buildings, the REN coupling solutions should consider a progressive swap from AC
injection to DC. Figure 1 gives the general principle of energy flow of the renewable energy or distributed DC power to
the existing power system of the building integrating an up to 400 VDC system.
LVAC
AC Board
HVAC
Rectifier/charger
grid up to 400VDC
∼
DC loads
=
AC back-up
Generator AC ICT, cooling,
other AC use Battery
(48V system, UPS)
AC
Generators using Renewable Energy sources, e.g.
DC bidirectional
Sun PV, wind turbine, water flow, green fuel (engine or fuel
DC nano grid
cell)
external
and/or interconnexion interface to DC nano/micro grid
to the building
Figure 1: General energy flow principle for coupling renewable or
distributed DC site grid to an up to 400 VDC power system in a building of a site
The flow direction is indicated by the arrow and reverse direction from REN to grid depends on excess of power not
used by the sites for powering ICT equipment, cooling and air conditioning equipment and building use could be sent to
the AC or DC grids. This is to avoid loss of productivity and to contribute to the local or regional nation electric mix
and CO reduction effort and to obtain a better TCO for the user.
2
Combined Heat and Power generation (CHP) and storage can be also alternatives, but they are not covered in the
present document focused on injection of electricity in DC and partly in AC.
4.2 Local and distant Renewable Energy coupling architecture
to sites with up to 400 VDC
There are different architectures for interconnections of local REN or distributed power systems or DC nano and micro
grid up to 400 VDC power systems in buildings or sites. It includes local renewable power sources:
• connected to AC and/or DC distribution:
- for local consumption;
- for local injection of excess of production into external grid;
• connected to an external DC nano or micro grid:
- for injection of excess of DC production towards other buildings or sites;
- for remote interconnection to the AC grid e.g. for mutualized injection of DC energy excess on one
single point;
- for islanding the group of sites when running on own distributed power production capacity (e.g. pure or
hybrid renewable energy source with energy storage).
ETSI
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12 Final draft ETSI ES 203 474 V1.1.0 (2018-01)
NOTE: The connection to DC nano or micro grid for different services is not fully covered in the present
document as R&D is still on-going in many directions such as swapping part of the AC grid power
systems to more energy coming from local renewable energy or from external DC nano or micro grid,
extending resilience of the site to face grid power interruption, taking advantage of smart grid services at
the level of the interconnection to AC grid e.g. renewable energy injection or storage to support the grid,
on demand peak shedding, etc.
Figure 2 gives the general principles of electrical coupling interconnection of the local REN or from DC from
nano/micro grid to the existing power systems of the building integrating up to 400 VDC systems. The power injection
can be done:
• in DC only;
• in AC only;
• in AC and DC.
DC outp
...
SLOVENSKI STANDARD
SIST ES 203 474 V1.1.1:2019
01-januar-2019
Okoljski inženiring (EE) - Vmesniško povezovanje obnovljivih energijskih ali
razpršenih elektroenergijskih virov s 400-voltnimi enosmernimi distribucijskimi
sistemi, ki napajajo opremo informacijske in komunikacijske tehnologije (IKT)
Environmental Engineering (EE) - Interfacing of renewable energy or distributed power
sources to 400 VDC distribution systems powering Information and Communication
Technology (ICT) equipment
Ta slovenski standard je istoveten z: ETSI ES 203 474 V1.1.1 (2018-03)
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
29.240.01 2PUHåMD]DSUHQRVLQ Power transmission and
GLVWULEXFLMRHOHNWULþQHHQHUJLMH distribution networks in
QDVSORãQR general
SIST ES 203 474 V1.1.1:2019 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ES 203 474 V1.1.1:2019
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SIST ES 203 474 V1.1.1:2019
ETSI ES 203 474 V1.1.1 (2018-03)
ETSI STANDARD
Environmental Engineering (EE);
Interfacing of renewable energy or distributed
power sources to 400 VDC distribution systems powering
Information and Communication Technology (ICT) equipment
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SIST ES 203 474 V1.1.1:2019
2 ETSI ES 203 474 V1.1.1 (2018-03)
Reference
DES/EE-0252
Keywords
power supply, renewable
ETSI
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SIST ES 203 474 V1.1.1:2019
3 ETSI ES 203 474 V1.1.1 (2018-03)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 Architecture of up to 400 VDC power with REN coupling . 10
4.1 Overview . 10
4.2 Local and distant Renewable Energy coupling architecture to sites with up to 400 VDC . 11
5 Conditions required to keep specified performance for the up to 400 V power system . 13
5.1 General introduction . 13
5.2 Electrical Stability . 13
5.2.1 General consideration on REN power injection. 13
5.2.2 DC injection of locally generated REN power . 14
5.2.3 AC injection of REN power . 14
5.3 Reliability, Maintainability, Safety . 14
5.4 Proper battery charge and management . 15
5.4.1 DC injection of REN power . 15
5.4.2 AC injection of REN power . 16
5.4.3 EMC, transient voltage and current surge limitation . 16
5.4.4 Protection of distribution cables and protection coordination . 16
6 Control-monitoring and metering . 17
7 Assessment of performances improvement of up to 400 VDC systems with REN power . 17
7.1 Reliability, efficiency performance assessment . 17
7.2 Operational KPI of REN coupling to sites with up to 400 VDC systems . 17
Annex A (informative): Different possible coupling architectures of REN energy to AC and
DC site powering systems or to nano or micro grid . 18
A.0 General view . 18
A.1 Interconnection of REN on single AC site input . 18
A.2 Interconnection of REN on single and multiple DC distribution . 19
A.3 Interconnection of REN on single or multiple AC distribution frame . 20
A.4 Hybrid interconnection of REN on AC and DC distribution . 22
A.5 Interconnection of REN to DC nano or micro grid . 23
Annex B (informative): Details on coupling solution of REN generator to an up to 400 VDC
system . 25
Annex C (informative): Control/Monitoring consideration for Renewable Energy system
connexion to AC and DC points in DC systems . 26
Annex D (informative): General consideration for sizing and power coupling of REN system
to up to 400 VDC systems . 28
ETSI
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SIST ES 203 474 V1.1.1:2019
4 ETSI ES 203 474 V1.1.1 (2018-03)
D.1 General conditions impacting on the REN sizing and power coupling . 28
D.2 Monosource system . 28
D.3 Multisources management and balance between power sources and backup batteries . 29
History . 30
ETSI
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SIST ES 203 474 V1.1.1:2019
5 ETSI ES 203 474 V1.1.1 (2018-03)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables 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 (https://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.
Trademarks
The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners.
ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does
not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks.
Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Environmental Engineering (EE).
The up to 400 VDC power solutions feeding the power interface to ICT equipment as defined by ITU-T
(Recommendation ITU-T L.1200 series [1], [2], [3], [i.1], [i.3]) and ETSI [8], are well adapted to straight forward use
of renewable energy or distributed power sources through new simple DC nano or micro grids. This series defines the
coupling of local or remote renewable energy into an up to 400 VDC power system without reducing DC performances
defined in Recommendation ITU-T L.1202 [2] mainly for efficiency and reliability. The main advantages are saving of
fossil fuel (as a source of primary energy consumption), reduction of GHG emission and increase of resilience.
Additional site interconnection by DC grid can even bring more optimization. One other big benefit is that compared to
AC, on 400 VDC there is no synchronization required between the various inputs, which keeps the architecture simple.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "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
The up to 400 VDC power feeding solution for ICT sites (datacenters, telecom centers) and other building using the up
to 400 VDC power interface Recommendation ITU-T L.1200 [1], are well adapted to straightforward use of renewable
energy or distributed power sources through new DC nano or micro grid, most of them being more complex in AC than
in DC. The DC would allow great simplification by avoiding frequency and phase synchronization of AC generators or
inverters.
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The present document aims at defining interface and architecture for injecting renewable energy into an up to 400 VDC
power system in charge of providing power to ICT and facilities equipment with an interface compliant to
Recommendation ITU-T L.1200 [1], and with a DC power architecture as defined in Recommendation
ITU-T L.1204 [i.3], without reducing DC performances defined in Recommendation ITU-T L.1202 [2] mainly for
efficiency and reliability.
The addition of local renewable energy will reduce energy consumption from the public utility, and possibly fossil
primary energy consumption and the corresponding high GHG emission.
It can also provide more resilience in case of public electric grid interruption.
In addition, energy exchange is simple with distributed green power sources e.g. photovoltaic, wind power, fuel cell
(FC) or engine generator using green fuel through a DC nano or micro grids at the level of a multi-building site or
between different sites. These sites can be any type of ICT sites such as network access or nodes, data-centers, customer
premises including IoT devices, etc.). Such an inter-buildings or sites power interconnection is called "site grid" by
opposition to public electric utility.
These DC energy exchanges through site grid can bring higher level of optimization such as:
• exploit green-energy sources more efficiently by optimal location of renewable energy generator (e.g. for wind
system in windy places and for PV system, in places out of shadow);
• complement local back-up power system e.g. battery;
• share local renewable energy excess of one site with other sites;
• ensure remote powering of distributed ICT site in the neighbourhood (e.g. by dedicated remote DC power
cables or hybrid optical and DC power cables).
Injection of the renewable energy into the legacy AC public utility should consider the use of electricity for ICT
services, and avoids undetermined use in the neighbourhood that can be inefficient. Key performance indicators could
be used for reducing inconsidered use by accounting for efficient use of renewable energy on one ICT site or
interconnected sites through a nano grid.
Many documents provided in bibliography are elaborating on the benefit and the need of coupling REN energy to local
installation or to nano grid [i.7], [i.14] to ICT installation and the advantages of doing it in DC [i.8], [i.9], [i.10], [i.11],
[i.12]. LCA approach is more detailed in [i.13].
The present document was developed jointly by ETSI TC EE and ITU-T Study Group 5 and published respectively by
ITU and ETSI as Recommendation ITU-T L.1205 [i.1] and ETSI ES 203 474 (the present document), which are
technically equivalent.
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1 Scope
The present document defines interconnection of site power installation feeding up to 400 VDC interface, to site
renewable energy or to distributed DC power. The covered aspects are:
• general power architectures for:
- connection of a site renewable energy source (PV, wind generator, fuel cells, etc.) to a site power plant
and especially the DC power system, (the site sources being on the buildings or around);
- exchange of power to and from a DC nano or micro grid for use and production out of the site (this
includes dedicated remote powering network built for ICT access equipment but also more general
purpose DC electric grids);
- conditions required to keep specified performance for the up to 400V power system:
electrical stability;
reliability and maintainability;
proper battery charge and management;
lightning protection coordination;
EMC and transient limits;
- specification of proper power sizing, Requirement for control-monitoring and power metering;
- assessment of performances (AC grid energy saving, reliability, flexibility, environmental impact, etc.).
The present document does not cover:
• renewable energy dimensioning;
• power injection into the legacy AC utilities which is already covered by many standards (e.g. from IEC);
• some of the smart power management possibilities through exchanges with DC nano or micro grid.
2 References
2.1 Normative 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
https://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.
The following referenced documents are necessary for the application of the present document.
[1] Recommendation ITU-T L.1200 (2012): "Direct current power feeding interface up to 400 V at the
input to telecommunication and ICT equipment".
[2] Recommendation ITU-T L.1202 (2015): "Methodologies for evaluating the performance of up to
400 VDC power feeding system and its environmental impact".
[3] Recommendation ITU-T L.1203 (2016): "Colour and marking identification of up to 400 VDC
power distribution for information and communication technology systems".
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[4] ETSI EN 301 605 (V1.1.1): "Environmental Engineering (EE); Earthing and bonding of 400 VDC
data and telecom (ICT) equipment".
[5] ETSI ES 202 336 (all parts): "Environmental Engineering (EE); Monitoring and Control Interface
for Infrastructure Equipment (Power, Cooling and Building Environment Systems used in
Telecommunication Networks)".
[6] IEC 60364 series: "Low-voltage electrical installations".
NOTE: Available at https://webstore.iec.ch/searchform&q=IEC%2060364.
[7] IEC 62368-1: "Audio/video, information and communication technology equipment - Part 1:
Safety requirements".
[8] ETSI ES 203 408 (V1.1.1) (2016-12): "Environmental Engineering (EE); Colour and marking of
DC cable and connecting devices".
2.2 Informative 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.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
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.1205 (October 2016): "Interfacing of renewable energy or distributed
power sources to up to 400 VDC power feeding systems".
[i.2] ETSI EN 302 099 (V2.1.1): "Environmental Engineering (EE); Powering of equipment in access
network".
[i.3] Recommendation ITU-T L.1204 (2016): "Extended architecture of power feeding systems of up to
400 VDC".
[i.4] Recommendation ITU-T L.1302 (2015): "Assessment of energy efficiency on infrastructure in
data centres and telecom centres".
[i.5] Recommendation ITU-T L.1350 (2016): "Energy efficiency metric of base station site".
[i.6] Recommendation ITU-T L.1410: "Methodology for environmental life cycle assessments of
information and communication technology goods, networks and services".
[i.7] K.K. Nguyen et al. (Projet GreenStar) (2011): "Renewable Energy Provisioning for ICT Services
in a Future Internet" Future Internet Assembly, LNCS 6656 (open access at SpringerLink.com),
pp. 421-431.
[i.8] IEEE/Intelec 2013 (Hamburg): "DC power wide spread in Telecom/Datacenter and in home/office
with renewable energy and energy autonomy", Didier Marquet and al. Orange Labs; Toshimitsu
Tanaka et al. NTT.
[i.9] Vicor White paper: "High-voltage DC distribution is key to increased system efficiency and
renewable-energy opportunities", Stephen Oliver.
NOTE: Available at http://www.vicorpower.com/documents/whitepapers/wp-High-voltage-DC-Distribution.pdf.
[i.10] STARLINE: "Phasing Out Alternating Current Directory: An Engineering Review of DC Power
for Data Centers", David E. Geary.
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[i.11] 400 VDC Power Solutions from Emerson Network Power: "Innovative Power Architecture for
Data Center and Telecommunications Sites".
NOTE: Available at https://www.vertivco.com/globalassets/products/critical-power/dc-power-systems/400v-dc-
power-solutions-brochure.pdf.
[i.12] IEEE/Intelec 2014 (paper quoted on Emerge Alliance): "Three Case Studies of Commercial
Deployment of 400V DC Data and Telecom Centers in the EMEA Region", Sara Maly Lisy,
Mirna Smrekar Emerson Network Power.
NOTE: Available at http://www.emergealliance.org/portals/0/documents/events/intelec/TS01-2.pdf.
[i.13] IREED 2011 (Lille 23-24 March 2011, 7 p): "Wiring design based on Global Energy Requirement
criteria: a first step towards an eco-designed DC distribution scheme", C. Jaouen, B. Multon,
F. Barruel.
[i.14] Micro grids: "A bright future".
NOTE: Available at http://www1.huawei.com/enapp/198/hw-110948.htm.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
back-up power system: power system providing energy to equipment of an ICT site in case of downstream electric
unavailability
distributed power source: local electrical power source where energy is produced close to the user and distributed by a
nano or micro grid by opposition to a centralized power plant with a long distance electricity transport grid
NOTE: This local power source can be an individual user power system or a small collective energy power plant
for a group of customers. It can include energy sources or storage or cogeneration of heat and electricity
using any primary energy renewable or not.
distributed power system: system of distributed power source and possibly other function such as energy conversion,
interconnection, safety system, energy storage and corresponding management
ICT equipment (Recommendation ITU-T L.1200 [1]): information and communication equipment (e.g. switch,
transmitter, router, server, and peripheral devices) used in telecommunication centres, data-centres and customer
premises
Interface P (Recommendation ITU-T L.1200 [1]): interface, physical point, at which power supply is connected in
order to operate the ICT equipment
nano grid, micro grid: local area grid connecting some building together at relatively short distance
NOTE: It can be in AC or DC. In general nano grid is lower than 100 kW, micro grid can be of higher power.
"Nano or micro grid" will be used in the present document.
renewable energy: energy which can be obtained from natural resources that can be constantly replenished
NOTE: Source: Australian Renewable energy Agency.
renewable energy source: source producing electrical energy from renewable energy
site grid: DC nano or micro grid between ICT sites by opposition to public electric utility
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3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AC Alternating Current
BMS Battery Management System
CHP Combined Heat and Power
CT Current Transducer
CU Control Unit
DC Direct Current
EE Energy Efficiency
EMC Electro-Magnetic Compatibility EMC
FC Fuel Cell
GHG Green House Gas
HV High Voltage
HVAC High Voltage AC
ICT Information and Communication Technology
IoT Internet of Things
KPI Key Performance Indicator
LCA Life Cycle Analysis
LVAC Low Voltage AC
LVDC Low Voltage DC
MW Megawatt
PDF Power Distribution Frame
PDU power Distribution Unit
Ppeak Peak power
Pu Used power
PV Photovoltaic
PWM Pulse Width Modulation
REN Renewable Energy
RF Rectifier Function
TCO Total Cost Ownership
VDC Volt DC
4 Architecture of up to 400 VDC power with REN
coupling
4.1 Overview
In existing buildings, AC grid (HVAC or LVAC) and LVAC distributions are powering ICT equipment, cooling
systems, back-up power systems, control/monitoring, lighting, office computers, Ethernet switches routers and many
other equipment in the building such as ventilation, heater, lifts, etc. A part of the equipment is DC powered by the DC
power feeding systems, and this part is mainly using 400 VDC rather than -48 VDC because of the higher power
density of equipment in order to reduce cable cross-section area and distribution losses.
ICT sectors work on the reduction of the non- renewable primary energy use by reducing direct electricity consumption
and producing more Renewable Energy (REN).
The REN generators are generally in LVDC and so power arrangement up to 400 VDC power systems is much more
convenient for injecting REN.
NOTE: REN generators that are in AC are generally producing variable frequency and voltage requiring precise
synchronization for connection to AC grid.
DC REN generators allow easier consumption of locally generated energy or generated by a group of close sites
through DC nano or micro grid compared to solution with local AC generator synchronized with AC grid.
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Due to the wide use of AC in ICT buildings, the REN coupling solutions should consider a progressive swap from AC
injection to DC. Figure 1 gives the general principle of energy flow of the renewable energy or distributed DC power to
the existing power system of the building integrating an up to 400 VDC system.
LVAC
AC Board
HVAC
Rectifier/charger
grid up to 400VDC
∼
DC loads
=
AC back-up
Generator AC ICT, cooling,
other AC use Battery
(48V system, UPS)
AC
Generators using Renewable Energy sources, e.g.
DC bidirectional
Sun PV, wind turbine, water flow, green fuel (engine or fuel
DC nano grid
cell)
external
and/or interconnexion interface to DC nano/micro grid
to the building
Figure 1: General energy flow principle for coupling renewable or
distributed DC site grid to an up to 400 VDC power system in a building of a site
The flow direction is indicated by the arrow and reverse direction from REN to grid depends on excess of power not
used by the sites for powering ICT equipment, cooling and air conditioning equipment and building use could be sent to
the AC or DC grids. This is to avoid loss of productivity and to contribute to the local or regional nation electric mix
and CO reduction effort and to obtain a better TCO for the user.
2
Combined Heat and Power generation (CHP) and storage can be also alternatives, but they are not covered in the
present document focused on injection of electricity in DC and partly in AC.
4.2 Local and distant Renewable Energy coupling architecture
to sites with up to 400 VDC
There are different architectures for interconnections of local REN or distributed power systems or DC nano and micro
grid up to 400 VDC power systems in buildings or sites. It includes local renewable power sources:
• connected to AC and/or DC distribution:
- for local consumption;
- for local injection of excess of production into external grid;
• connected to an external DC nano or micro grid:
- for injection of excess of DC production towards other buildings or sites;
- for remote interconnection to the AC
...
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