1、 International Telecommunication Union ITU-T L.1200TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2012) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Direct current power feeding interface up to 400 V at the input to telecommunication and ICT
2、equipment Recommendation ITU-T L.1200 Rec. ITU-T L.1200 (05/2012) i Recommendation ITU-T L.1200 Direct current power feeding interface up to 400 V at the input to telecommunication and ICT equipment Summary Recommendation ITU-T L.1200 specifies the direct current (DC) interface between the power fee
3、ding system and ICT equipment connected to it. It also describes normal and abnormal voltage ranges, and immunity test levels for ICT equipment to maintain the stability of telecommunication and data communication services. The specified interface is operated from a DC power source of up to 400 V to
4、 allow increased power consumption and equipment power density, in order to obtain higher energy efficiency and reliability with less material usage than using a lower voltage such as 48 VDC or AC UPS power feeding solutions. History Edition Recommendation Approval Study Group 1.0 ITU-T L.1200 2012-
5、05-29 5 Keywords Data centre, direct current, energy efficiency, ICT equipment, power feeding system, reliability, telecommunication centre. ii Rec. ITU-T L.1200 (05/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunicat
6、ions, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunicatio
7、ns on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure la
8、id down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunic
9、ation administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these man
10、datory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws
11、 attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or
12、others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not repre
13、sent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T L.1200 (05/20
14、12) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 DC power feeding interface specification 2 6.1 Definition of DC power feeding interface 3 6.2 Voltage r
15、ange at interface P . 3 6.3 Reference test voltage (UT) at interface P 4 6.4 Abnormal conditions 4 6.5 Inrush current 7 Appendix I Information on grounding method . 8 I.1 Basic configuration . 8 I.2 Specification for PE at interface P 8 Bibliography. 10 iv Rec. ITU-T L.1200 (05/2012) Introduction Th
16、is Recommendation specifies a power feeding system for ICT equipment with a DC voltage of up to 400 V. This Recommendation takes into consideration the improvements in energy efficiency as well as the reduction in greenhouse gas (GHG) emissions and raw materials that are enabled by using the up to 4
17、00 VDC power feeding system. The up to 400 VDC power feeding system was developed, due to increased power consumption and equipment power density, in order to obtain a higher energy efficiency with less material consumption than using a lower voltage such as 48 VDC or AC UPS power feeding solutions.
18、 One of the advantages of up to 400 VDC power feeding is that it reduces intermediate power conversion stages (e.g., the inverter and power factor compensator can be eliminated) and it is lower current usage than 48 V feeding for the same power requirement, thereby improving the efficiency and relia
19、bility of the entire power feeding system. This Recommendation is concerned with the requirements for the interface between the power feeding system and telecommunication and ICT equipment. It also includes requirements relating to its stability, safety and measurement. Reliability and scalability a
20、re easier to improve in DC compared to AC because phase synchronization and inverters are not required. The system architecture is also simpler. The purpose of the up to 400 VDC interface is to facilitate interworking of different loads, standardization of power feeding systems for ICT equipment, an
21、d installation, operation and maintenance of ICT equipment and systems with different origins. In addition, the DC interface can also simplify the use of renewable energy power sources with DC output such as photovoltaic generators and fuel cell systems. Rec. ITU-T L.1200 (05/2012) 1 Recommendation
22、ITU-T L.1200 Direct current power feeding interface up to 400 V at the input to telecommunication and ICT equipment 1 Scope This Recommendation is aimed at providing compatibility between the power feeding system and ICT equipment installed at telecommunication centres, data centres and customer pre
23、mises. This Recommendation deals with the requirements for an up to 400 VDC interface between power feeding system and ICT equipment. This Recommendation covers the following main items: The identification of a power feeding system with the same characteristics for all ICT equipment defined in any l
24、ocation where an up to 400 VDC interface is used, e.g., telecommunication centres, radio base stations, data centres and customer premises. The up to 400 VDC voltage range in normal and abnormal service conditions at the interface defined in this Recommendation. Behaviour during voltage variation, d
25、ips, short interruptions, transients, inrush current, grounding, etc. The general requirements for safety and earthing and bonding are out of the scope of this Recommendation unless specific requirements are not defined in current standards. 2 References The following ITU-T Recommendations and other
26、 references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged t
27、o investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document,
28、the status of a Recommendation. IEC 60445 IEC 60445 (2010), Basic and safety principles for man-machine interface, marking, and identification Identification of equipment terminals, conductor terminations, and conductors. IEC 61000-4-5 IEC 61000-4-5 (2005), Electromagnetic compatibility (EMC) Part 4
29、-5: Testing and measurement techniques Surge immunity test. IEC 61000-4-29 IEC 61000-4-29 (2000), Electromagnetic compatibility (EMC) Part 4-29: Testing and measurement techniques Voltage dips, short interruptions and voltage variations on d.c. input power port immunity tests. ETSI EN 300-132-3-1 ET
30、SI EN 300-132-3-1 (2012), 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 subpart 1: direct current (DC) up to 400 V s
31、olution. 2 Rec. ITU-T L.1200 (05/2012) 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 abnormal DC voltage range: DC voltage range at interface P where ICT equipment may not operate within its specificati
32、on, but is not damaged. 3.2.2 DC voltage range: DC voltage range at interface P. 3.2.3 ICT equipment: Information and communication equipment (e.g., switch, transmitter, router, server, and peripheral devices) used in telecommunication centres, data centres and customer premises. 3.2.4 interface P:
33、Interface, physical point, at which power feeding system is connected to operate ICT equipment. Refer to Figure 1. 3.2.5 normal DC voltage range: DC voltage range at interface P where ICT equipment operates within its specification. 3.2.6 power feeding system: Power source to which ICT equipment is
34、intended to be connected. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AC Alternating Current (also when used as a suffix to units of measurement) DC Direct Current (also when used as a suffix to units of measurement) EMC Electromagnetic Compatibili
35、ty GHG Green House Gas ICT Information and Communication Technology PE Protective Earth Rg Resistance for the grounding system UPS Uninterruptible Power Supply UTReference test voltage Vooutput Voltage of power feeding system VDC Volts DC 5 Conventions None. 6 DC power feeding interface specificatio
36、n This clause describes the DC power feeding interface to ICT equipment in data centres, telecommunication centres and customer premises. Rec. ITU-T L.1200 (05/2012) 3 6.1 Definition of DC power feeding interface L.1200(12)_F01(+)()PEInterface PPower feedingsystem ICT equipmentFigure 1 Definition of
37、 interface P The power feeding interface, shown as interface P in Figure 1, is a physical point at which all the requirements apply. This point is situated between the power feeding system and ICT equipment in accordance with IEC 60445. In this clause, all specifications are defined at the input of
38、ICT equipment. Figure 2 shows a typical use of interface P. L.1200(12)_F02AC power DC powerAC mains AC/DCconverterICT equipmentInterface PBatterysystemPower feeding systemRectifierDefinitions such as DC voltage range is defined at this interface pointFigure 2 Illustration of power feeding system and
39、 ICT equipment 6.2 Voltage range at interface P 6.2.1 Normal DC voltage range The maximum environmental benefit will only be achieved by transitioning towards a single voltage interface: the target solution. However, it is also recognized that there have already been some regional developments in DC
40、 for powering ICT equipment. To take advantage of the benefits resulting from a single voltage range interface (the target solution), a transitional period will be specified during which a transitional solution is allowed towards the single DC voltage range at the input of the ICT equipment. The tar
41、get delay for full implementation of the target solution shall be as short as possible from the date of publication of this Recommendation. Target solution This solution has the following characteristics: The normal voltage range is the range of steady-state voltage over which ICT equipment shall ma
42、intain a specified normal service. The minimum voltage is 260 V. The maximum voltage is 400 V. 4 Rec. ITU-T L.1200 (05/2012) The voltage at the output of the power supply must take into account the voltage drop in the cable at a maximum steady current. Any new ICT equipment or electrical room instal
43、lation compliant with this Recommendation shall use this target voltage range (260-400 V). Transitional solution The transitional voltage range over which ICT equipment shall maintain a specified normal service is 192 V-288 V. This can be used for the migration of DC systems towards the recommended
44、target voltage range for a limited time in some regions. 6.2.2 Abnormal DC voltage range ICT equipment may be subjected to steady-state voltage out of the normal DC voltage range for the target solution. The limits of an abnormal DC voltage range for the target solution are defined as follows: 0 V 1
45、 s) interruption of the operating voltage at interface P. NOTE 1 With reference to clauses 6.1.1 and 6.1.2 of IEC 61000-4-29 the definition of low impedance is a generator output impedance 100 k . NOTE 2 The purpose of the second test above (“High impedance“) is to test the performance of the system
46、 during a power start-up of the system from 0 V (i.e., all system capacitors are fully discharged). This reflects the reset of a tripped circuit-breaker on interface P or DC interruptions in the network caused by transient voltage. This reset can also occur with the recovery of interface P voltage f
47、ollowing the restoration of AC mains after an AC mains interruption longer than the battery backup time. 6.4.4 Voltage surges/transients The voltage surges at interface P shall be tested by referring to IEC 61000-4-5 and ETSI EN 300-132-3-1. The condition and compliance criteria for testing are in T
48、able 4. Voltage surges may occur at interface P when faults (e.g., short circuits) occur in the power distribution system. The voltage surges due to short circuits and protective device clearance are characterized by a voltage drop in the abnormal voltage range, followed by an overvoltage often in e
49、xcess of the maximum abnormal voltage range and dependent upon the power distribution up to interface P and the ICT equipment connected to interface P. The purpose of this clause is thus to address the energy and subsequent so-called “fuse blowing surge“ associated with a short circuit. Other voltage surges induced from other external sources, e.g., faults on the AC mains or lightning, belong to EMC generic requirements and are outside the scope of this Recommendation. Due to the lack of commercial test generators f
