SIST EN 300 132-2 V2.2.2:2008
Environmental Engineering (EE) - Power supply interface at the input to telecommunications equipment - Part 2: Operated by direct current (dc)
- Abstract
The present document contains requirements for:
- the output performance of the direct current (DC) power equipment at the interface "A";
- the input of the telecommunications equipment connected to interface "A" powered by DC.
The DC voltage at interface "A" may be derived from the AC primary supply. The DC supply may incorporate a backup battery. If any other equipment e.g. datacom equipment, are connected to interface "A" in parallel to telecommunications equipment, all requirements addressed in clause 4 of the present document must be fulfilled. The present document aims at providing compatibility between the power supply equipment and the power consuming telecommunications equipment, and also between different system blocks connected to the same power supply. NOTE 1: The present document is applicable only to -48 VDC power supply interfaces. However, during a
transitional period, other DC voltages may be used in existing installations. Annex A gives guidance on working in conjunction with existing -60 VDC supply systems.
The power supply interface, interface "A", is a physical point to which all the requirements are related (see figure 1). This point is situated between the power supply system(s) and the power consuming telecommunications equipment. NOTE 2: Interface "A" is located at the power terminals of the telecommunications equipment. Subject to the installation preconditions this point may be located at any other point between the power supply system and the telecommunications equipment by mutual agreement of the relevant parties. The requirements at interface "A" apply to:
- the output of the power supply equipment or power supply installation of telecommunications centres;
- the power supply input of telecommunications equipment installed at telecommunication centres;
- telecommunications equipment, installed in customers' premises, whose DC interface "A" is also used by equipment requiring a supply to this specification.
NOTE 3: Normally there is more than one load unit connected to interface "A". In these cases, interface "A" will undergo further restrictions with respect to noise limits or other disturbances specified in clause 4.8. NOTE 4: Disturbances on the power supply interface "A" relating to the continuous wave phenomena below 20 kHz are covered within the present document.
NOTE 5: An example of a configuration in which interface "A" is identified is given in annex D.
- Status
- Published
- Publication Date
- 30-Jan-2008
- Technical Committee
- I16 - ETSI Technical Committee
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 17-Jan-2008
- Due Date
- 23-Mar-2008
- Completion Date
- 31-Jan-2008
SIST EN 300 132-2 V2.2.2:2008 is the Slovenian adoption of ETSI EN 300 132-2 for the power supply interface at the input to telecommunications equipment, Part 2 for equipment operated by direct current (DC). It specifies the electrical conditions at interface "A" between a DC power supply and telecommunications equipment, so designers, operators, test labs, and buyers can align equipment and power systems to the same interface requirements. The document is centered on -48 VDC interfaces and on compatibility, disturbance limits, and test methods at that interface.
What does SIST EN 300 132-2 V2.2.2:2008 specify?
SIST EN 300 132-2 V2.2.2:2008 sets requirements for the output performance of the DC power equipment at interface "A" and for the DC input of telecommunications equipment connected to that interface. It also covers compatibility where several load units share the same power supply.
The document is organized into scope, references, definitions, requirements, earthing and bonding, electrical safety, EMC requirements, and informative annexes. Clause 4 is the core technical part.
| Annex | What it covers |
|---|---|
| A | Guidance for working with existing -60 VDC systems |
| B | Measuring inrush current and transferring pulses onto the limit chart |
| C | Test arrangements for injecting electrical noise at interface "A" |
| D | Examples for identifying interface "A" |
| E | Wideband noise and its calculation or measurement |
| F | Protection dimensioning |
| G | Bibliography |
What are the key requirements of SIST EN 300 132-2 V2.2.2:2008?
Clause 4 gives the operating voltage window, abnormal-voltage survivability, transient immunity, current limits, inrush limits, and noise limits. In practice, these are the checks used to see whether a power-fed telecommunications system will keep running without damaging equipment or tripping protection.
Voltage and recovery behavior
- Nominal voltage at interface "A" is -48 VDC with the positive conductor connected to earth. This is the reference condition for design and testing.
- Normal service voltage range is -40.5 VDC to -57.0 VDC. Equipment is expected to operate within specification across this range.
- Abnormal steady-state voltage range includes 0.0 VDC to -40.5 VDC and -57.0 VDC to -60.0 VDC. Equipment must survive these conditions without damage.
- After return to normal voltage, service must recover automatically and without manual intervention. This matters for network continuity after supply disturbance.
Transients and supply changes
- Clause 4.3.3 requires verification with the EN 61000-4-5 combination wave generator using a 500 V positive-polarity transient under the stated battery configurations. This checks resistance to faults in the power distribution system.
- Clause 4.4 covers voltage changes due to power-supply regulation, with a 6 V ± 10 % step and a 3 V/ms to 7 V/ms rate. The equipment must keep operating to specification with no data loss or false alarm.
Current draw, inrush, and protection
- Clause 4.5 requires supply protection by circuit breakers, fuses, or equivalent devices, and the inrush energy must be considered when sizing the system.
- Clause 4.6 limits current drain after abnormal service to 1.5 times the maximum continuous current drain at nominal voltage if the condition lasts longer than 1 second. This protects fuses and distribution equipment.
- Clause 4.7 limits inrush current using the curve in figure 3 and defines the measurement circuit. Annex B explains how to measure complex pulse shapes correctly.
- Clauses 4.8 and 4.9 set conducted immunity and conducted emissions limits at interface "A" for narrowband noise below 20 kHz.
What terms does SIST EN 300 132-2 V2.2.2:2008 define?
- interface "A" - The terminals at which the telecommunications equipment connects to the power supply system.
- normal service voltage range - The steady-state voltage range in which the equipment is expected to maintain normal service.
- abnormal voltage range - The steady-state voltage range in which the equipment is not expected to maintain normal service but must remain undamaged.
- maximum continuous input current - The manufacturer-stated continuous input current for fully equipped equipment at nominal voltage.
- system block - A functional group of equipment that depends on the same power supply to operate and perform.
- EUT - Equipment Under Test, the item being checked in the test setup.
- LISN - Line Impedance Stabilization Network, used to simulate the power-network impedance during measurement.
- EMC - Electromagnetic Compatibility, the broader discipline that includes the conducted disturbance tests in this document.
Who uses SIST EN 300 132-2 V2.2.2:2008?
Telecommunications equipment designers use it to define the DC input behavior their products must tolerate. Power-supply designers and system integrators use it to size distribution, protection, and battery-backed feeds around a common interface.
Test laboratories use it for voltage, inrush, transient, and noise measurements at interface "A". Operators, installers, and maintenance teams use it when combining equipment from different origins in telecommunication centres or customer premises. Quality managers and buyers use it to confirm that equipment and supply systems are built for the same DC feeding conditions.
Which standards are used with SIST EN 300 132-2 V2.2.2:2008?
Clause 2 cites the main referenced standards used for protection, bonding, transients, and measurement methods:
- IEC 60269-1 - Low-voltage fuses, used when considering fuse behavior and inrush protection.
- EN 60934 - Circuit-breakers for equipment, used for breaker behavior in the inrush-current limit.
- EN 300 253 - Earthing and bonding of telecommunication equipment in telecommunication centres.
- ITU-T Q.551 to Q.554 - Transmission characteristics of digital exchanges and analogue interfaces, used in the wideband noise context.
- ITU-T O.41 - Psophometer for telephone-type circuits, used for psophometric noise measurement.
- EN 61000-4-5 - Surge immunity test, used for the voltage transient verification.
The foreword also places this document in the ETSI series with Part 1 for AC operated from DC sources and Part 3 for rectified current source, AC source, or DC source up to 400 V.
What does the SIST EN 300 132-2 V2.2.2:2008 document contain?
The document contains measurement setups, limit curves, and worked test methods rather than only abstract requirements. Annex B gives practical guidance for recording inrush pulses and plotting them against the limit chart. Annex C shows example noise-injection arrangements, and Annex E explains both measured and calculated approaches to wideband noise.
The main text includes figures for interface "A", the transient generator test circuit, the inrush-current test circuit, and the narrowband emission and immunity arrangements. These are the parts readers use when building a test plan, qualifying equipment, or checking a power system design against the interface requirements.
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Frequently Asked Questions
SIST EN 300 132-2 V2.2.2:2008 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Environmental Engineering (EE) - Power supply interface at the input to telecommunications equipment - Part 2: Operated by direct current (dc)". This standard covers: The present document contains requirements for: - the output performance of the direct current (DC) power equipment at the interface "A"; - the input of the telecommunications equipment connected to interface "A" powered by DC. The DC voltage at interface "A" may be derived from the AC primary supply. The DC supply may incorporate a backup battery. If any other equipment e.g. datacom equipment, are connected to interface "A" in parallel to telecommunications equipment, all requirements addressed in clause 4 of the present document must be fulfilled. The present document aims at providing compatibility between the power supply equipment and the power consuming telecommunications equipment, and also between different system blocks connected to the same power supply. NOTE 1: The present document is applicable only to -48 VDC power supply interfaces. However, during a transitional period, other DC voltages may be used in existing installations. Annex A gives guidance on working in conjunction with existing -60 VDC supply systems. The power supply interface, interface "A", is a physical point to which all the requirements are related (see figure 1). This point is situated between the power supply system(s) and the power consuming telecommunications equipment. NOTE 2: Interface "A" is located at the power terminals of the telecommunications equipment. Subject to the installation preconditions this point may be located at any other point between the power supply system and the telecommunications equipment by mutual agreement of the relevant parties. The requirements at interface "A" apply to: - the output of the power supply equipment or power supply installation of telecommunications centres; - the power supply input of telecommunications equipment installed at telecommunication centres; - telecommunications equipment, installed in customers' premises, whose DC interface "A" is also used by equipment requiring a supply to this specification. NOTE 3: Normally there is more than one load unit connected to interface "A". In these cases, interface "A" will undergo further restrictions with respect to noise limits or other disturbances specified in clause 4.8. NOTE 4: Disturbances on the power supply interface "A" relating to the continuous wave phenomena below 20 kHz are covered within the present document. NOTE 5: An example of a configuration in which interface "A" is identified is given in annex D.
The present document contains requirements for: - the output performance of the direct current (DC) power equipment at the interface "A"; - the input of the telecommunications equipment connected to interface "A" powered by DC. The DC voltage at interface "A" may be derived from the AC primary supply. The DC supply may incorporate a backup battery. If any other equipment e.g. datacom equipment, are connected to interface "A" in parallel to telecommunications equipment, all requirements addressed in clause 4 of the present document must be fulfilled. The present document aims at providing compatibility between the power supply equipment and the power consuming telecommunications equipment, and also between different system blocks connected to the same power supply. NOTE 1: The present document is applicable only to -48 VDC power supply interfaces. However, during a transitional period, other DC voltages may be used in existing installations. Annex A gives guidance on working in conjunction with existing -60 VDC supply systems. The power supply interface, interface "A", is a physical point to which all the requirements are related (see figure 1). This point is situated between the power supply system(s) and the power consuming telecommunications equipment. NOTE 2: Interface "A" is located at the power terminals of the telecommunications equipment. Subject to the installation preconditions this point may be located at any other point between the power supply system and the telecommunications equipment by mutual agreement of the relevant parties. The requirements at interface "A" apply to: - the output of the power supply equipment or power supply installation of telecommunications centres; - the power supply input of telecommunications equipment installed at telecommunication centres; - telecommunications equipment, installed in customers' premises, whose DC interface "A" is also used by equipment requiring a supply to this specification. NOTE 3: Normally there is more than one load unit connected to interface "A". In these cases, interface "A" will undergo further restrictions with respect to noise limits or other disturbances specified in clause 4.8. NOTE 4: Disturbances on the power supply interface "A" relating to the continuous wave phenomena below 20 kHz are covered within the present document. NOTE 5: An example of a configuration in which interface "A" is identified is given in annex D.
SIST EN 300 132-2 V2.2.2:2008 is classified under the following ICS (International Classification for Standards) categories: 19.040 - Environmental testing; 33.050.01 - Telecommunication terminal equipment in general. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 300 132-2 V2.2.2:2008 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Okoljski inženiring (EE) - Napajalni vmesnik na vhodu v telekomunikacijsko opremo - 2. del: Obratovanje z enosmerno napetostjo (dc)Environmental Engineering (EE) - Power supply interface at the input to telecommunications equipment - Part 2: Operated by direct current (dc)33.050.01Telekomunikacijska terminalska oprema na splošnoTelecommunication terminal equipment in general19.040Preskušanje v zvezi z okoljemEnvironmental testingICS:Ta slovenski standard je istoveten z:EN 300 132-2 Version 2.2.2SIST EN 300 132-2 V2.2.2:2008en01-marec-2008SIST EN 300 132-2 V2.2.2:2008SLOVENSKI
STANDARD
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 2
Reference REN/EE-02008[4] Keywords interface, power supply 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 Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the 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 http://portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: http://portal.etsi.org/chaircor/ETSI_support.asp Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2007. All rights reserved.
DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. TIPHONTM and the TIPHON logo are Trade Marks currently being registered by ETSI for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. SIST EN 300 132-2 V2.2.2:2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 3
Contents Intellectual Property Rights.5 Foreword.5 1 Scope.6 2 References.7 3 Definitions, symbols and abbreviations.8 3.1 Definitions.8 3.2 Symbols.9 3.3 Abbreviations.9 4 Requirements.9 4.1 Nominal voltage.9 4.2 Normal service voltage range at interface "A".9 4.3 Abnormal service voltage range at interface "A".10 4.3.1 Abnormal service voltage under steady-state conditions.10 4.3.2 Recovery from steady state abnormal voltage.10 4.3.3 Voltage transients.10 4.3.4 Recovery from voltage transients.11 4.4 Voltage changes due to the regulation of the power supply.11 4.4.1 Test conditions.11 4.4.2 Performance criteria.11 4.5 Supply protection at interface "A".12 4.6 Maximum current drain following abnormal service.12 4.7 Inrush Current on connection of interface "A".12 4.7.1 Limits.12 4.7.2 Measurements.13 4.8 Conducted immunity requirements of the telecommunications equipment at interface "A".13 4.8.1 Immunity to narrowband noise.14 4.9 Conducted emissions requirements of the telecommunications equipment at interface "A".15 5 Earthing and bonding.17 6 Electrical safety requirements.17 7 EMC requirements.17 Annex A (informative): -60 VDC systems.18 Annex B (informative): Guide for measuring inrush current and for transferring the recorded pulses onto the limit chart.19 B.1 Measurement.19 B.2 Pulse waveform transformation.19 B.3 Measurement of inrush current with filter capacitor current pulses.22 Annex C (informative): Test arrangements for the injection of electrical noise at interface "A".25 Annex D (informative): Identification of interface "A".26 Annex E (informative): Wideband noise.27 E.1 Emission of wideband noise.27 E.1.1 Assessment of wideband noise.27 E.2 How to calculate wideband emission.27 SIST EN 300 132-2 V2.2.2:2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 4
Annex F (informative): Protection dimensioning.31 Annex G (informative): Bibliography.32 History.33
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 5
Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Environmental Engineering (EE). The present document concerns the requirements for the interface between telecommunications equipment and its power supply, and includes requirements relating to its stability and measurement. Various other references and detailed measurement and test arrangements are contained in informative annexes. The present document is part 2 of a multi-part deliverable covering Environmental Engineering (EE); Power supply interface at the input to telecommunications equipment, as identified below: Part 1: "Operated by alternating current (ac) derived from direct current (dc) sources"; Part 2: "Operated by direct current (dc)"; Part 3: "Operated by rectified current source, alternating current source or direct current source up to 400 V".
National transposition dates Date of latest announcement of this EN (doa): 31 January 2008 Date of latest publication of new National Standard or endorsement of this EN (dop/e):
31 July 2008 Date of withdrawal of any conflicting National Standard (dow): 31 July 2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 6
1 Scope The present document contains requirements for: - the output performance of the direct current (DC) power equipment at the interface "A"; - the input of the telecommunications equipment connected to interface "A" powered by DC. The DC voltage at interface "A" may be derived from the AC primary supply. The DC supply may incorporate a backup battery. If any other equipment e.g. datacom equipment, are connected to interface "A" in parallel to telecommunications equipment, all requirements addressed in clause 4 of the present document must be fulfilled. The present document aims at providing compatibility between the power supply equipment and the power consuming telecommunications equipment, and also between different system blocks connected to the same power supply. NOTE 1: The present document is applicable only to -48 VDC power supply interfaces. However, during a transitional period, other DC voltages may be used in existing installations. Annex A gives guidance on working in conjunction with existing -60 VDC supply systems. The power supply interface, interface "A", is a physical point to which all the requirements are related (see figure 1). This point is situated between the power supply system(s) and the power consuming telecommunications equipment. NOTE 2: Interface "A" is located at the power terminals of the telecommunications equipment. Subject to the installation preconditions this point may be located at any other point between the power supply system and the telecommunications equipment by mutual agreement of the relevant parties. The requirements at interface "A" apply to: - the output of the power supply equipment or power supply installation of telecommunications centres; - the power supply input of telecommunications equipment installed at telecommunication centres; - telecommunications equipment, installed in customers' premises, whose DC interface "A" is also used by equipment requiring a supply to this specification. NOTE 3: Normally there is more than one load unit connected to interface "A". In these cases, interface "A" will undergo further restrictions with respect to noise limits or other disturbances specified in clause 4.8. NOTE 4: Disturbances on the power supply interface "A" relating to the continuous wave phenomena below 20 kHz are covered within the present document. NOTE 5: An example of a configuration in which interface "A" is identified is given in annex D. SIST EN 300 132-2 V2.2.2:2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 7
Interface "A"telecommunicationsequipmentSystem blockDC power supply conductors Figure 1: Identification of interface "A" The purpose of the present document is: - to use a power supply system with the same characteristics for all telecommunications equipment defined in the area of application; - to facilitate inter working of different (types of) load units; - to facilitate the standardization of telecommunications equipment; - to facilitate the installation, operation and maintenance in the same network of equipment and telecommunications systems from different origins. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication and/or edition number or version number) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, the latest version applies. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity. [1] IEC 60269-1: "Low-voltage fuses - Part 1: General requirements". [2] CENELEC EN 60934: "Circuit-breakers for equipment (CBE)". [3] ETSI EN 300 253: "Environmental Engineering (EE); Earthing and bonding of telecommunication equipment in telecommunication centres". [4] ITU-T Recommendation Q.551: "Transmission characteristics of digital exchanges". [5] ITU-T Recommendation Q.552: "Transmission characteristics at 2-wire analogue interfaces of digital exchanges". SIST EN 300 132-2 V2.2.2:2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 8
[6] ITU-T Recommendation Q.553: "Transmission characteristics at 4-wire analogue interfaces of digital exchanges". [7] ITU-T Recommendation Q.554: "Transmission characteristics at digital interfaces of digital exchanges". [8] ITU-T Recommendation O.41: "Psophometer for use on telephone-type circuits". [9] CENELEC EN 61000-4-5: "Electromagnetic compatibility (EMC) - Part 4-5: Testing and measurement techniques - Surge immunity test". 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: abnormal voltage range: range of steady-state voltage over which the equipment will not be expected to maintain normal service but will survive undamaged customer premises: any location which is the sole responsibility of the customer fully equipped equipment: generally there are several maximum configurations because different boards can be used in the same slots NOTE: The fully-equipped equipment configuration shall be the configuration that corresponds to the maximum power consumption measured at -48 VDC e.g. not in standby mode. interface "A": terminals at which the power supply is connected to the system block NOTE 1: See also figure 1. NOTE 2: This is a functional definition and not an exact depiction of the physical location. load unit: power-consuming equipment, that is part of a system block maximum continuous input current: maximum continuous input current, stated by the manufacturer, for a fully-equipped equipment under test connected to interface "A", at nominal voltage (accordance clauses 4.6 and 4.7.1 of the present document) nominal voltage: nominal value of the voltage that designates the type of supply normal service: service mode where telecommunications equipment operates within its specification normal service voltage range: range of steady-state voltages over which the equipment will maintain normal service power supply: power source to which telecommunications equipment is intended to be connected system block: functional group of equipment depending for its operation and performance on its connection to the same power supply NOTE: A system block may consist of equipment or a functional group of equipment. Different examples of configurations at interface "A" are given in annex D. telecommunication centre: location where telecommunications equipment is installed and which is the sole responsibility of the operator SIST EN 300 132-2 V2.2.2:2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 9
3.2 Symbols For the purposes of the present document, the following symbols apply: It instantaneous surge current (see clause 4.7.1) Im maximum continuous input current L inductance of inductive element of LISN R resistance of resistive element of LISN t time Zc capacitive impedance of immunity measurement circuit Zm resistive impedance of immunity measurement circuit 3.3 Abbreviations For the purposes of the present document, the following abbreviations apply: CDN Coupling/Decoupling Network DC direct current NOTE: Also when used as a suffix to units of measurement. EMC ElectroMagnetic Compatibility EUT Equipment Under Test LISN Line Impedance Stabilization Network RF Radio Frequency rms root mean square NOTE: Also when used as a suffix to units of measurement. 4 Requirements 4.1 Nominal voltage The nominal value of the voltage at interface "A" shall be -48 VDC (positive conductor is connected to earth). NOTE 1: In most cases the voltage of interface "A" will be complemented by a 24 cell lead-acid battery. NOTE 2: During a transitional period, other DC voltages may be used in existing installations. Annex A gives guidance on merging equipment with existing -60 VDC supply systems. 4.2 Normal service voltage range at interface "A" The normal service voltage range for the -48 VDC nominal supply at interface "A" shall be -40,5 VDC to -57,0 VDC. NOTE 1: The minimum voltage is based on the voltage drop in the distribution network and a battery cell end of discharge voltage. NOTE 2: The voltages specified are measured at interface "A". It should be noted that if interface "A" is at any point other than the telecommunications equipment interface there will be a voltage drop between interface "A" and the equipment terminals. NOTE 3: When the voltage is in the range -40,5 VDC to -44,0 VDC it is recognized that there may be a slight degradation of service performance. SIST EN 300 132-2 V2.2.2:2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 10 4.3 Abnormal service voltage range at interface "A" 4.3.1 Abnormal service voltage under steady-state conditions Telecommunications equipment operated at -48 VDC shall not suffer any damage when subjected to the following voltage ranges: 0,0 VDC to -40,5 VDC and -57,0 VDC to -60,0 VDC
4.3.2 Recovery from steady state abnormal voltage Following the restoration of the supply to the normal voltage range, the power conversion and management systems on the load side of interface "A" shall automatically restore service. The telecommunications equipment shall then resume operation according to its specifications. The abnormal service voltage shall not lead to the disconnection of the power supply e.g. by causing circuit breakers, fuses or other such devices to operate. NOTE: It is acceptable that the system may restart when the voltage is -40,5 V or greater within the nominal service voltage range and/or after a time delay. 4.3.3 Voltage transients Voltage transients may occur at interface "A" when faults occur in the power distribution system. These transients are characterized by a voltage drop in the range: 0 VDC to 40,5 VDC, followed by an overvoltage often in excess of the maximum steady state abnormal service voltage range and dependent upon the power distribution up to interface "A" and the equipment connected to interface "A".
The performance of telecommunication equipment against this abnormal overvoltage shall be verified using the combination wave generator defined in the basic standard EN 61000-4-5 [9]. This generator has the pulse shape of 1,2 μs-rise time/50 μs-duration in open circuit and 8μs-rise time/20μs-duration in short circuit. The voltage transient wave generator test circuit is shown in figure 2.
Figure 2: Voltage transient generator wave test circuit Telecommunication
equipment
EUTInterface "A" Wave Generator and CDN + - dc power sourceR = 2 Ω SIST EN 300 132-2 V2.2.2:2008
ETSI ETSI EN 300 132-2 V2.2.2 (2007-10) 11 The test has to be performed applying an overvoltage of 500V (positive polarity, reference of the generator shall be connected to the positive pole of battery) at the interface "A" of the telecommunication equipment with 2 Ohm impedance of the test generator. The test has to be performed in the following two battery configuration: • positive of b
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