1、CEPT T/TR*02-02*E 232bIL4 0010382 II T/TR 02-02 E Page 1 Recommendation T/TR 02-02 (Innsbruck 1981, revised in Montpellier 1984 and Copenhagen 1987) e RACK/TELECOMMUNICATIONS CENTRE POWER SUPPLY INTERFACE Recommendation proposed by Working Group T/WG 12 “Transmission” (TR) Text of Recommendation ado
2、pted by the “Telecommunications” Commission: “The European Conference of Posts and Telecommunications Administrations, considering - that telecommunications equipments usually be installed in telecommunications centres and held in racks, cabinets - that the installation of racks from various origins
3、 require to be standardised, - that the existing CCITT and CCIR Recommendations in such matters do not ensure the required standardisation, - that the CCITT and CCIR do not envisage standardising the rack/telecommunications centre power supply interface, - that the Administrations are amenable to th
4、e harmonisation of equipment and telecommunications, which will lead to a lowering of development and manufacturing costs for the industry which is supplying equipment to several countries, or other mechanical structures, recommends that the members of the CEPT should apply the rack/telecommunicatio
5、ns centre power supply interface specifications contained in this Recommendation.” Edition of February 29, 1988 CEPT T/TR*02-02*E T/TR 02-02 E i Page2 Table of contents 1 . AREA OF APPLICATION 2 . OBJECTIVES 3 3 . SPECIFICATIONS . 3.1. 3.2. Nominal values of the secondary voltage (main supply) . 3.3
6、. Secondary voltages (supplementary supply) introduced in the rack Permitted tolerances of secondary voltages in normal service . Permitted tolerance of secondary voltages in accidental service Voltage changes due to regulation of the secondary voltage Maximum value of supply current Number of secon
7、dary voltage (main supply introduced into the rack) . 3.4. 3.5. 3.6. 3.7. . 3.8. Protection at the input of the rack converters . 3.9. Surge current on connection of rack . 3.10. Maximum levels of noise present on the 48V and 6OV DC suppes 3.1 1 . Maximum levels of noise re-injected by each noise so
8、urce connected to the secondary distribution of power at Interface “A” . 3.12. Electromagnetic radiations emitted into the immediate surroundings by each noise source in the rack . 3.13. Acoustic disturbances emitted by each noise source in the rack in both audible and ultrasonic ranges . . 3.14. Co
9、nnections at Interface “A” 3.15. Earthing of the rack 3.16. Remote power supplies for buried equipment . 3 3 3 3 4 4 5 5 5 5 6 Page 3 Edition of February 29. 1988 CEPT T/TR*02-02*E = 2326414 0010384 5 T/TR 02-02 E Page 3 1. AREA OF APPLlCATfON The power supply interface (Interface “A”) of Figure 1 (
10、T/TR 02-02) applies to: - Secondary power supply of telecommunications centres. - Secondary power distribution. - All telecommunications equipment installed in telecommunications centres, except electromechanical - Administrations telecommunications equipment installed in subscribers premises. The e
11、quipment concerned should be developed in such a way that the power supply specification is observed at a physical point, located between the rack input and the power cabling of the telecommunications centre or subscribers premises. The specification of the AC primary (e.g. mains/local AC generator)
12、 supply is not included in this Recommendation. switching equipments. 2. OBJECTIVES - To use the same secondary supply for all telecommunications equipment defined in the area of applica- - To facilitate the harmonisation of telecommunications equipment. - To facilitate the installation, operating a
13、nd maintenance in the same network, of equipment and - To define the power supply interface between the rack or other mechanical structure and telecommunica- tion. telecornmunications systems from different origins. tions centres or subscribers premises. 3. SPECIFIC ATIONS 3.1. Number of secondary v
14、oltages (main supply) introduced into the rack One or two voltages may be introduced into the rack (for instance 2 x 48V DC or 48V DC and another voltage, e.g. 220V AC) independent of the number of inputs. Nominal values of the secondary voltages (main supply) The specified nominal values are: 48V D
15、C 60V DC 3.2. 220V ACIS0 Hz Notes. i. The nominal value of secondary voltage is a designation for the type of supply. The actual voltage at Interface “A” during normal service is any value between those defined in section 3.4. 2. The majority of Administrations have selected for the long term a nomi
16、nal voltage of 48V DC. Some Administrations continue to use a nominal voltage of 60V DC. 3. In this Recommendation, it is not specified how the secondary supply is produced. - The DC secondary voltage may be derived from the AC primary supply with or without a buffer battery. - The AC secondary volt
17、age may be derived from (a) a stabilised AC supply (e.g. inverter or AC conditioner); (b) directly from the AC primary supply where the quality of this supply is sufficient for telecommunications 4. When a main voltage of 400/230V AC is adopted in Europe following the IEC study the nominal value and
18、 permitted tolerances of the 220V AC supply will be reconsidered. 5. During a transitional period, other DC voltages may be used in existing stations. 6. The 220V AC supply can be constituted either by two phases of a 3-phase secondary voltage or by one phase and neutral. equipment to meet its speci
19、fication. 3.3. 3.3.1. Secondary voltages (supplementary supply) introduced into the rack If for rack alarm signalling equipment as well as for the rack alarm indication units (e.g. alarm lamps), a power supply at Interface “A” other than those mentioned in 3.2. is necessary, the voltage used shall e
20、ither be 48V DC or 60V DC. Notes. i, The majority of Administrations have selected for the long term a nominal voltage of 48V DC. Some Administrations continue to use a nominal voltage of 60V DC. 2. The specifications of points 3.4. and after do not apply for this supplementary supply unless otherwi
21、se specified by the Administrations. Edition of February 29, 1988 CEPT T/TR*02-02*E 2326434 -I 1 T/TR02-02 E Page 4 3.3.2. Where a 220V AC socket in the rack is specified for measuring instruments, soldering irons, or illuminating equipment it should be possible to use distributed AC voltage as spec
22、ified in section 3.2. Permitted tolerances of secondary voltages in normal service The permitted tolerances are respectively: For 48V DC nominal: 40.5 to 57V DC (Note 2) For 60V DC nominal: 50 to 72V DC For 220V AC nominal: Notes. 1. “Normal Service” means that the supply voltage is such that ali th
23、e specifications are met by the equipment. 2. For an intermediate period, it is tolerated that the specifications of some equipments may be slightly degraded in the voltage range 40.5 to 44V DC. In the longer term ali the equipment will be guaranteed to meet its specifications over the whole range.
24、3. Telecommunications equipment tolerates frequency deviations of the supply voltage in the range f 2 Hz without alteration of the specifications. Certain peripherals require a closer tolerance, typically f 1 Hz or less. For this equipment a stabilised AC supply may be specified in accordance with I
25、EC Publication 686. 3.4. 198 to 242V AC/50 Hz f 2 Hz (Note 3) 3.5. Permitted tolerance of secondary voltages in accidental service Note. By accidental service one means that the secondary voltage is such that equipments do not meet their specifications but do not suffer any damage. Accidental servic
26、e under settled conditions In this case, telecommunications equipment should not suffer any damage in the following voltage ranges: O to 40.5V DC and 57 to 60V for 48V DC nominal O to 50V DC and 72 to 75V for 60V DC nominal O to 198V AC and The frequency tolerance for 220V AC, 50 Hz nominal is f 5 H
27、z. After the restoration of nominal voltage conditions, the equipment should work again without manual intervention being necessary. The accidental service should not lead to the disconnection of power supply units by tripping circuit breakers or blowing fuses. For particular equipment (e.g. master
28、oscillators, pilot frequency generators, etc.) Administrations will define a maximum permitted time for that equipment to meet its specifications after the restoration of normal conditions. This time interval will be related to the duration of the accidental conditions. Accidental service under temp
29、orary conditions In this case, telecommunications equipment should not suffer any damage when a transient voltage of up to 200V DC is present for up to 100 microseconds on the 48V DC and 60V DC nominal supplies. After the restoration of nominal voltage conditions, the equipment should work again wit
30、hout manual interven- tion being necessary. The accidental service should not lead to the disconnection of power supply units by tripping circuit breakers or blowing fuses. Note. Lower values of transient voltage may exist for longer periods of time but these are not included in this Recommendation.
31、 Common-mode overvoltage: In order to prevent damage to equipment caused by common-mode transient overvoltages superimposed on the secondary power distribution, it is required that the equipment withstand a waveform produced by the generator G shown in Figure 4 (T/TR 02-02), applied as shown in Figu
32、re 5A (T/TR 02-02). The value of the open-circuit voltage is under study; it should be chosen in accordance with IEC Publication 664. Diferential-mode overvoltage: In order to prevent damage to equipment caused by differential-mode transient overvoltages superimposed on the secondary power distribut
33、ion, it is required that the equipment withstand a waveform produced by the generator G shown in Figure 4 (T/TR 02-02), applied as shown in Figure 5B (T/TR 02-02). The value of the open-circuit voltage is under study; it should be chosen in accordance with IEC Publication 664. The impulsive test wav
34、eform should be applied to the equipment under test (EUT) 10 times, 5 for each polarity, with an interval of 30 seconds between subsequent applications. 3.5.1. 242 to 254V for 220V AC nominal 3.5.2. Edition of February 29, 1988 CEPT T/TR*02-02*E 2326414 0010386 9 3.6. 3.6. 3.6.2 3.7. 3.7.1. 3.7.2. 3
35、.8. 3.9. 3.9.1. T/TR 02-02 E Page 5 Voltage changes due to regulation of the secondary voltage DC supplies Where the technique of regulation of battery voltage by the connection of cells is used, equipment specifications should be met under maximum transition rates of 5V/ms for both the fall and ris
36、e of the secondary supply. The voltage at Interface “A” should remain within the limits of section 3.4., i.e. in the range 40.5 to 57V DC for 48V DC nominal and 50 to 72V DC for 60V DC nominal supplies respectively. AC power supply: voltage changes due to regulating action or intervention of continu
37、ity units Voltage interruptions: In the case of automatic switching of power supplies (for continuity purposes) short interruptions of voltage may occur. The equipment shall meet its specifications when the duration of the interruption is equal to or less than 50ms. Slow voltagepuctuations: In the c
38、ase of regulation of secondary voltage following load changes, slow voltage fluctuations and frequency variations may occur. The equipment shall meet its specifications when the envelope of the voltage fluctuations is as shown in Figure 6 (T/TR 02-02) and the frequency variation is up to 3 Hz with a
39、 recovery time of 5 seconds. Maximum value of supply current Transmission rack The maximum value of the power supply current at the minimum voltage as specified in section 3.4. should be as follows: DC Supply: AC Supply: Notes. I. The limits are derived from the values for the maximum rack dissipati
40、on as defined in Recommendation T/TR 02-03 and related to Type A (nominal width 120mm) and Type B (nominal width 600mm) racks, of the nominal height of 2,60Omm, as described in Recommendation T/TR 02-01. 2. The values refer to normal working and may be exceeded in the case of partial rack failure; i
41、n consequence they will be applied for the planning of the secondary power room and not for gauging the protection devices against overloads. 3. For racks which supply power to remote equipment the values of the power supply current may be higher. 4. The ratio between the peak and RMS value of the c
42、urrent should not exceed 3.5 : 1. Switching rack This point is related to the study of mechanical structures for future telecommunications equipment (e.g. ISDN) and is therefore not included in this Recommendation. 2.OA for the rack of Type A (Note I) 10.0A for the rack of Type B (Note I) 0.8A RMS f
43、or the rack of Type A (Note 4) 3.5A RMS for the rack of Type B (Note 4) Protection at the input of the rack converters The supply of the racks should be protected upstream of Interface “A” by fuses or circuit breakers placed in a power distribution bay. Before putting equipment in service it should
44、be possible to suppress the action of any possible fuses placed between Interface “A” and the converters. Surge current on connection of rack The ratio of instantaneous surge current I, to maximum current I, at Interface “A” under any random sequence of switching operations should not exceed the lim
45、its shown in Figure 2 (T/TR 02-02) for 48V or 60V DC and in Figure 3 (T/TR 02-02) for 220V AC. The time origin of Figure 2 (T/TR 02-02) shall be taken at the time ordinate where It suitable diameters shall be between 5 and 50cm. The equipment should be powered at the nominal secondary voltage and ra
46、ted load condition. Acoustic disturbances emitted by each noise source in the rack in both audible and ultrasonic ranges The level of acoustic noise (SPL) should be measured via a microphone at a distance of 0.5m from each surface, all round the equipment, which should be installed in a rack of typi
47、cal configuration placed in an “anechoic” chamber. The worst level of acoustic noise generated by the equipment should not exceed the limits shown in Figure 7 (T/TR 02-02) per Y3 octave band, nor a frequency weighted value of 30dBA (i.e. measured via the IEC weighting network A). The measurements as
48、sociated with Figure 7 (T/TR 02-02) should be made using Y3 octave band filters in accordance with IEC Publication 225 extended upwards to 40 kHz. The weighted measurement should be made with a soundmeter in accordance with IEC Publication 179 using weighting network A. Edition of February 29, 1988
49、CEPT T/TR*02-02*E m 232b434 0030389 4 m T/TR 02-02 E Page 8 3.14. 3.15. 3.16. 3.16.1, 3.16.2. Connections at Interface “A” The connection of secondary voltages to the rack should be possible by cable. Note. It is permitted to connect to the rack by power supply bars if the rack configuration permits, in the case of DC power supply. Earthing of the rack The HF and protection earth is carried by cables or bars having large cross-sections. The positive pole of the secondary DC supply voltage is earthed at the rack level and/or in the power room, according to the station earth
