1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T K.34TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2003) SERIES K: PROTECTION AGAINST INTERFERENCE Classification of electromagnetic environmental conditions for telecommunication equipment Basic EMC Recommendation ITU-T Recommendation K.34 ITU-T Rec
2、. K.34 (07/2003) i ITU-T Recommendation K.34 Classification of electromagnetic environmental conditions for telecommunication equipment Basic EMC Recommendation Summary This Recommendation defines electromagnetic environmental classes for telecommunication equipment covering all relevant electromagn
3、etic environmental parameters. This Recommendation applies to telecommunication equipment installed in telecommunication centres, outdoor locations and customer premises. This is a basic EMC Recommendation for telecommunications. Source ITU-T Recommendation K.34 was approved by ITU-T Study Group 5 (
4、2001-2004) under the ITU-T Recommendation A.8 procedure on 29 July 2003. ii ITU-T Rec. K.34 (07/2003) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a pe
5、rmanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, estab
6、lishes 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 laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary sta
7、ndards 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 telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Re
8、commendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation 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
9、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 attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed I
10、ntellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, 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 re
11、ceived notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2003 All rights reserv
12、ed. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. K.34 (07/2003) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 4 Abbreviations 2 5 Electromagnetic environmental parameters . 3 5.1 Electrostatic voltage .
13、3 5.2 Electrical Fast Transient/Burst (EFT/B). 4 5.3 Conducted radio-frequency voltages 4 5.4 Radio-frequency fields . 4 5.5 d.c. voltages 4 5.6 16 2/3 Hz voltages 5 5.7 50 Hz/60 Hz voltages . 5 5.8 Audio frequency voltages. 5 5.9 Surges . 5 5.10 Voltage variation 5 5.11 Voltage fluctuation . 5 5.12
14、 Voltage interruption 5 5.13 Audio frequency magnetic fields 5 5.14 Lightning electromagnetic pulse 5 5.15 Low frequency repetitive impulses 6 6 Characteristics of environments . 6 6.1 Telecommunication centres (common features for class 1 and class 2) 6 6.2 Class 3 Outdoor locations 7 6.3 Class 4 C
15、ustomer premises 7 7 Characteristic severities of the environmental parameters . 8 Appendix I Bibliography 15 iv ITU-T Rec. K.34 (07/2003) Introduction This Recommendation is a compilation of data concerning electromagnetic environmental conditions. The phenomena covered by this Recommendation are:
16、electrostatic discharges (ESD); electrical fast transients/bursts (EFT/B); conducted radio-frequency disturbances; radiated radio-frequency disturbances; d.c. voltages; 16 2/3 Hz voltages; 50 Hz/60 Hz voltages; audio frequency voltages; surges; voltage variations; voltage fluctuations; voltage inter
17、ruptions; audio frequency magnetic fields; lightning electromagnetic pulses; low frequency repetitive impulses. The data included in this Recommendation are based on calculation, analysis and experience, supported by comprehensive environmental surveys where such surveys exist. Certain assumptions o
18、n the installation practice are necessary when characterizing the electromagnetic environment. If these assumptions are not satisfied in a particular case, the environmental characteristic may not apply. Each environment is characterized in two ways: by a short verbal description; by a quantitative
19、statement of the characteristic severities of the phenomena. The appropriate EMC requirements for telecommunication equipment should be based on the severity of the electromagnetic environment. The EMC requirements ensure that the equipment has a sufficient intrinsic immunity to enable it to operate
20、 as intended in its environment. It is emphasized that the characteristic severity of a phenomenon or parameter does not automatically indicate the test level used in immunity testing. Other considerations, e.g., priority of service of the equipment in question and technical and economic circumstanc
21、es should also be taken into account when selecting the test level of those given in basic standards on test methods. This Recommendation is a basic EMC Recommendation for telecommunications. ITU-T Rec. K.34 (07/2003) 1 ITU-T Recommendation K.34 Classification of electromagnetic environmental condit
22、ions for telecommunication equipment Basic EMC Recommendation 1 Scope This Recommendation defines classification of the electromagnetic environmental conditions encountered where telecommunication equipment is installed. This Recommendation applies to telecommunication equipment installed in telecom
23、munication centres, outdoor locations and customer premises. It does not make references to equipment dependent details. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At th
24、e time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed belo
25、w. 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, the status of a Recommendation 1 IEC/TR2 61000-2-5:1995, Electromagnetic compatibility (EMC) Part 2: Environment Section
26、5: Classification of electromagnetic environments. Basic EMC publication. 2 ITU-T Recommendation K.27 (1996), Bonding configurations and earthing inside a telecommunication building. 3 ITU-T Recommendation K.18 (1988), Calculation of voltage induced into telecommunication lines from radio station br
27、oadcasts and methods of reducing interference. 4 ITU-T Recommendation K.23 (1988), Types of induced noise and description of noise voltage parameters for ISDN basic user networks. 5 IEC 60050-161:1990, International Electrotechnical Vocabulary. Chapter 161: Electromagnetic Compatibility. 6 ITU-T Rec
28、ommendation K.33 (1996), Limits for people safety related to coupling into telecommunications system from a.c. electric power and a.c. electrified railway installations in fault conditions. 3 Definitions The following definitions apply only in the context of this Recommendation, except where the ref
29、erence to the International Electrotechnical Vocabulary 5 is given adjacent to the subclause title. 3.1 burst (161-02-07): A sequence of a limited number of distinct pulses or an oscillation of limited duration. 3.2 characteristic severity: The characteristic severity for a certain detail parameter
30、in an environmental class states a severity which has only a low probability, generally less than 1%, of being exceeded. The term relates to duration, rate of occurrence or location. It applies to 2 ITU-T Rec. K.34 (07/2003) requirements on the environment and to immunity requirements. In reference
31、1, the term “disturbance degree“ is used as the quantitative characterization of the environmental parameters. 3.3 continuous disturbance (161-02-11): Electromagnetic disturbance the effect of which on a particular device or equipment cannot be resolved into a succession of distinct effects. 3.4 env
32、ironment; environmental conditions: The electromagnetic conditions external to the equipment, to which it is subjected for a certain time. The environmental conditions comprise a combination of single environmental parameters and their severities. 3.5 environmental class: A representation of the env
33、ironment on locations with similar properties. They are specified and standardized to provide an operational frame of reference for: requirements on the environment; immunity requirements. The class is described using an envelope of environmental conditions expressed in terms of a number of environm
34、ental parameters and their characteristic severities or other characteristics. The environmental parameters specified for the class are limited to those which may affect equipment performance. 3.6 environmental parameters: The environmental parameters present one or more properties of the electromag
35、netic environment. 3.7 immunity (to a disturbance) (161-01-20): The ability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance. 3.8 pulse (161-02-02): An abrupt variation of short duration of a physical quantity followed by a rapid retur
36、n to the initial value. 3.9 Radio Frequencies (RF): The frequency range above 9 kHz. 3.10 rise time (of a pulse) (161-02-05): The interval of time between the instants at which the instantaneous value of a pulse first reaches a specified lower value and then a specified upper value. NOTE Unless othe
37、rwise specified, the lower and upper values are fixed at 10% and 90% of the pulse magnitude. 3.11 shielding effectiveness: For a given external source, the ratio (usually expressed in dB) of electric or magnetic field strength at a point before and after the placement of the shield in question. 3.12
38、 transient (adjective or noun) (161-02-01): Pertaining to or designating a phenomenon or a quantity which varies between two consecutive steady states during a time interval short compared with the time scale of interest. 3.13 Audio Frequencies (AF): The frequency range from 50 Hz to 20 kHz. 4 Abbre
39、viations This Recommendation uses the following abbreviations: a.c. alternating current AF Audio Frequency d.c. direct current EFT/B Electrical Fast Transient/Burst EMC Electromagnetic Compatibility ESD Electrostatic Discharge HV High Voltage ITU-T Rec. K.34 (07/2003) 3 IEC International Electrotech
40、nical Commission ISM Industrial, Scientific and Medical (equipment) ITE Information Technology Equipment RF Radio Frequency 5 Electromagnetic environmental parameters 5.1 Electrostatic voltage Persons walking on the floor or moving otherwise, or handling electrostatically charged objects are charged
41、 to an electrostatic voltage resulting as an Electrostatic Discharge (ESD) which may cause malfunction or even damage of equipment. The discharge may normally occur when the equipment is operated manually, or during maintenance or repair. The discharge may take place from the fingertips or via metal
42、lic tools to all accessible parts of the equipment. The risk is particularly high in locations with synthetic flooring materials or when the relative humidity is low, e.g., due to low outdoor temperature. The severity of the discharge depends on the clothing materials and the insulating properties o
43、f the soles of the shoes worn by the operator. The risk is almost eliminated if the relative humidity is above 50%. Figures 1 and 2 give guidance on the levels that may be observed dependent on the materials used and the environment in which the system is operating. This information has been used in
44、 the classification. 1615141312111098765432151020 304050 6070 80 9010K.034_F1Voltage(kV)SyntheticWoolAntistaticRelative humidity (%)Figure 1/K.34 Maximum values of electrostatic voltages to which operators may be charged while in contact with the materials in the absence of any electrostatic protect
45、ion measures 4 ITU-T Rec. K.34 (07/2003) 20 40 60 80 1000108642K.034_F20Ordinary shoesAntistatic shoesLinoleum floorVoltage(kV)RunWalkRunWalkRelative humidity (%)Figure 2/K.34 Maximum value of electrostatic voltage to which operators may be charged in telecommunication central office 5.2 Electrical
46、Fast Transient/Burst (EFT/B) Breaking of currents in a.c. and d.c. power supplies results in intermittent arcing across the contact. The phenomenon is repetitious and continues until the energy stored in the circuit has been dissipated. A sequence of voltage spikes is generated on the leads. These t
47、ransients propagate on the line in question and couple to adjacent signal and power lines. 5.3 Conducted radio-frequency voltages Different types of radio transmitters and switch mode power supplies induce common and differential mode voltages to power and signal lines. References 3 and 4 contain mo
48、re information on this parameter. 5.4 Radio-frequency fields Telecommunication equipment is directly exposed to fields of broadcasting, amateur and mobile radio transmitters. Particularly the modern cellular mobile and personal communication service systems operating at high frequencies may couple e
49、ffectively to printed circuit board level and not only to long lines. Radars are the main source of pulse modulated fields above 1 GHz. 5.5 d.c. voltages d.c. voltages apply to signal lines entering the building. Telecommunication equipment may be exposed to high d.c. voltages because of the use of cable fault location equipment. d.c. power plants for traction systems causing d.c. potential differences on telecommunication lines are not taken into account. Also induced voltages from geomagnetic activity are not
