1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T L.1202 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2015) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Methodologies for evaluating the performance of an up to 400
2、 VDC power feeding system and its environmental impact Recommendation ITU-T L.1202 Rec. ITU-T L.1202 (04/2015) i Recommendation ITU-T L.1202 Methodologies for evaluating the performance of an up to 400 VDC power feeding system and its environmental impact Summary Recommendation ITU-T L.1202 is provi
3、ded as a complement to Recommendation ITU-T L.1201, which describes the architecture of direct current (DC) power systems with an up to 400 VDC information and communication technology (ICT) equipment interface. The up to 400 VDC ICT equipment interface is described in Recommendation ITU-T L.1200. R
4、ecommendation ITU-T L.1202 provides a framework for assessing performances of up to 400 VDC power feeding systems and the savings incurred when compared to other power feeding systems such as the 48 VDC power system and the AC uninterruptable power system (UPS) commonly used in information and commu
5、nication technology (ICT) sites. This Recommendation deals with performance factors such as efficiency, reliability/availability and environmental impact. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T L.1202 2015-04-22 5 11.1002/1000/12427 _ * To access the Recommendation,
6、 type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T L.1202 (04/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized
7、agency in the field of telecommunications, 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 v
8、iew to standardizing telecommunications 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 Recommend
9、ations is covered by the procedure laid 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 concis
10、eness to indicate both a telecommunication 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 Recommendat
11、ion is achieved when all of these mandatory 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. I
12、NTELLECTUAL PROPERTY RIGHTSITU draws 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,
13、 whether asserted by ITU members or 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 a
14、re cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permiss
15、ion of ITU. Rec. ITU-T L.1202 (04/2015) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Comparative evaluation of energy efficiency of up to 400 VDC systems . 3 5.1 Acc
16、uracy and additional measurements . 3 5.2 AC input power factor 4 5.3 System energy efficiency . 4 5.4 Energy efficiency of ICT equipment PSU 5 5.5 Comparative energy efficiency of the power feeding system 5 6 Methodology for evaluating the reliability/availability performance of up to 400 VDC power
17、 feeding systems . 5 6.1 Reliability model for system failure rate and availability assessment . 5 7 Methodologies for evaluating environmental impact of up to 400 VDC systems . 9 7.1 Input current total harmonic distortion of the system 10 7.2 EMC, noise of power feeding system and PSU equipment 10
18、 7.3 Electrostatic discharge immunity of the DC system and DC PSU . 10 Appendix I Energy efficiency performance evaluation 11 I.1 General calculation principle 11 I.2 ATIS evaluation of rectifier efficiency . 13 Appendix II Measured efficiency values on AC UPS and up to 400 VDC power systems 14 II.1
19、 Test conditions 14 II.2 Test results 14 II.3 Analysis of the test results 15 Appendix III Reliability/dependability evaluation method 16 III.1 Reliability performance 16 III.2 The quantitative approach 16 III.3 Dependability performance 17 Appendix IV Reliability in EMerge Alliance and TGG . 20 App
20、endix V Availability calculation 22 Appendix VI Examples of availability calculations . 24 VI.1 Availability in Tier . 24 VI.2 Availability for the power feeding systems described in ITU-T L.1201 . 25 Appendix VII Availability comparison between power feeding architectures . 26 Bibliography. 27 iv R
21、ec. ITU-T L.1202 (04/2015) Introduction The architecture of direct current (DC) power systems with an up to 400 VDC ICT equipment interface ITU-T L.1200 is recommended in ITU-T L.1201. This Recommendation compliments ITU-T L.1201 providing a framework for assessing the performances of up to 400 VDC
22、power feeding systems and savings incurred when compared to other power feeding systems such as the 48 VDC power system and the AC UPSs commonly used in ICT sites. Energy efficiency results obtained by applying this Recommendation can be used as input for the evaluation of the energy efficiency perf
23、ormance of DC power systems for up to 400 VDC equipment in data centres and telecommunication centres. A comparative assessment approach as described in ITU-T L.1320 allows an energy efficiency measurement of the up to 400 VDC power feeding system at the level of the equipment to be compared with th
24、e energy efficiency measurement of other power equipment. A gain in energy savings of 5% to 20% has been assessed for the up to 400 VDC power feeding system in many papers and presentations (see Bibliography). This Recommendation also reports other benefits in terms of reliability, maintainability,
25、scalability and reduced electric power disturbance when compared to AC UPS and distribution systems. This Recommendation provides assessment tools for reliability and recommends comparative assessment methods. Gains are also foreseen in terms of battery use and in terms of the environmental impact a
26、nd waste reduction with a reduced electronic conversion stage. As there is no loss in inverters with fewer current ripples, the battery can last longer or its capacity can be slightly reduced. This Recommendation recommends using the general life cycle environmental assessment method described in IT
27、U-T L.1410 as the basic approach. Rec. ITU-T L.1202 (04/2015) 1 Recommendation ITU-T L.1202 Methodologies for evaluating the performance of an up to 400 VDC power feeding system and its environmental impact 1 Scope This Recommendation provides a comparative performance assessment of the up to 400 VD
28、C power feeding system using the interface described in ITU-T L.1200 and installed in telecommunications centres, data centres and customer premises, to determine the environmental savings of the new power feeding architectures defined in ITU-T L.1201. The performances evaluated include efficiency p
29、erformance, reliability performance and environmental impact over life cycle, based on ITU-T Recommendations on metrics and assessment methodologies. Other issues such as electrical disturbances, EMC, scalability and maintenance performance are partially covered. 2 References The following ITU-T Rec
30、ommendations and other 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
31、therefore encouraged to 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
32、stand-alone document, the status of a Recommendation. ITU-T L.1200 Recommendation ITU-T L.1200 (2012), Direct current power feeding interface up to 400 V at the input to telecommunication and ICT equipment. ITU-T L.1201 Recommendation ITU-T L.1201 (2014), Architecture of power feeding systems of up
33、to 400 VDC. ITU-T L.1320 Recommendation ITU-T L.1320 (2014), Energy efficiency metrics and measurement for power and cooling equipment for telecommunications and data centres. ITU-T L.1410 Recommendation ITU-T L.1410 (2014), Methodology for environmental life cycle assessments of information and com
34、munication technology goods, networks and services. IEC 62040-3 IEC 62040-3:2011, Uninterruptible power systems (UPS) Part 3: Method of specifying the performance and test requirements. ATIS-0600015.04.2010 ATIS-0600015.04.2010, Energy Efficiency for Telecommunication Equipment: Methodology for Meas
35、urement and Reporting DC Power Plant Rectifier Requirements. 3 Definitions 3.1 Terms defined elsewhere None. 2 Rec. ITU-T L.1202 (04/2015) 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 availability (performance): The ability of an item to be in a sta
36、te to perform a required function under given conditions at a given instant of time or over a given time interval, assuming that the required external resources are provided. NOTE 1 This ability depends on the combined aspects of the reliability performance, the maintainability performance and the m
37、aintenance support performance. NOTE 2 Required external resources, other than maintenance resources do not affect the availability performance of the item. 3.2.2 dependability: The collective term used to describe the availability performance and its influencing factors: reliability performance, ma
38、intainability performance and maintenance support performance. NOTE Dependability is used only for general descriptions in non-quantitative terms. 3.2.3 reliability (performance): The ability of an item to perform a required function under given conditions for a given time interval. NOTE 1 It is gen
39、erally assumed that the item is in a state to perform this required function at the beginning of the time interval. NOTE 2 Generally, reliability performance is quantified using appropriate measures. In some applications, these measures include an expression of reliability performance as a probabili
40、ty, which is also called reliability. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AC Alternating Current COP Coefficient of Performance DC Direct Current EMC Electromagnetic Compatibility ICT Information and Communication Technology MTBF Mean Time
41、Between Failures MTTR Mean Time To Repair PDU Power Distribution Unit PFC Power Factor Correction PSU Power Supply Unit TEER Telecommunications Energy Efficiency Ratio THD Total Harmonic Distortion UPS Uninterruptable Power System VDC Volts DC 5 Comparative evaluation of energy efficiency of up to 4
42、00 VDC systems This clause presents parameters of up to 400 VDC power feeding systems concerning energy efficiency assessment such as the input power factor, power system energy efficiency and ICT equipment power supply unit (PSU) energy efficiency. The energy saving characteristics of up to 400 VDC
43、 power systems can be assessed and compared to UPS or 48 VDC systems. Rec. ITU-T L.1202 (04/2015) 3 The system energy efficiency shall be defined considering the general power feeding architecture to be as recommended in ITU-T L.1201 and shall be assessed from the power feeding AC input (AC UPS, up
44、to 400 VDC power feeding system, etc.) to the output of the alternating current (AC) or direct current (DC) PSU inside the ICT equipment. Figure 1 shows the basic architecture considered for this efficiency assessment from power input to output. In AC and up to 400 VDC power feeding systems, when th
45、e rectifiers have no insulation, a transformer is used between the AC input and the rectifier input and its efficiency shall be taken into account. The energy efficiency measurement shall be made according to the assessment principle of ITU-T L.1320. In addition, for more precise determination and e
46、specially for a comparative benchmark between power feeding architectures, the efficiency shall be assessed in terms of instant power and in terms of consumed energy over a defined period. This is to take into account second order parameters such as load rate variation and thermal environments varia
47、tion for components with power efficiency characteristics depending on these parameters. For this purpose, full characteristics of power system elements (rectifiers, AC UPS and AC or DC PSU) including their load rates and temperatures shall be provided by manufacturers upon user request. The purpose
48、 of this Recommendation is to propose a more precise assessment of efficiency performance and a comparative benchmark of power feeding architectures e.g., 48 VDC or AC UPS or up to 400 VDC power feeding architectures, from the AC input to the input of the ICT device PSU. According to ATIS-0600015.04
49、.2010, the evaluation of rectifier efficiency for up to 400 VDC power feeding systems shall be performed using the TEER ratio (see Appendix I.2). The telecommunications energy efficiency ratio (TEER) is measured from 30% to 80% load rates at every 10% on reference test loads at the output of the rectifier and system with defined AC input characteristics. These load rates are expected in the operational area of the rectifier in the field. Examples of efficiency values are given for d
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