1、 International Telecommunication Union ITU-T K.96TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2014) SERIES K: PROTECTION AGAINST INTERFERENCE Surge protective components: Overview of surge mitigation functions and technologies Recommendation ITU-T K.96 Rec. ITU-T K.96 (02/2014) i Recommendati
2、on ITU-T K.96 Surge protective components: Overview of surge mitigation functions and technologies Summary Recommendation ITU-T K.96 presents information on the basic forms of surge mitigation and component technologies available to device and equipment designers. Following this basic Recommendation
3、, further Recommendations in this surge protective components series will describe the applications principles of specific component technologies. History Edition Recommendation Approval Study Group Unique ID*1.0 ITU-T K.96 2014-02-13 5 11.1002/1000/12129 Keywords Current limiters, filters, impulse
4、generators, mitigation, surge, transformers, voltage limiters. _ *To access the Recommendation, 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 K.96 (02/2014
5、) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized 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 st
6、udying 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, establishes the topics for study by the ITU-T study gr
7、oups 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 standards are prepared on a collaborative basis with
8、 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 Recommendation may contain certain mandatory provis
9、ions (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 are used to express requirements. The use of su
10、ch 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 Intellectual Property Right. ITU takes no positi
11、on 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 received notice of intellectual property, protect
12、ed by patents, which may be required to implement this Recommendation. However, implementers are 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 2014 All rights reserved. No part of
13、this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T K.96 (02/2014) 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 acro
14、nyms 3 5 Protection or mitigation or suppression? 4 6 Surge mitigation functions 4 6.1 Non-linear protective functions 4 6.2 Linear suppression functions 5 7 Component technologies and characteristics 5 7.1 Surge mitigation functions . 5 7.2 Non-linear limiting . 5 7.3 Linear suppression 8 Appendix
15、I Impulse (surge) generators used for low-voltage surge testing . 13 I.1 Introduction 13 I.2 Types of impulse generator 13 I.3 Impulse generator parameters . 13 I.4 Impulse generators typically used for surge protector testing 15 I.5 1.2/50-8/20 combination wave generator . 19 I.6 Expanding single o
16、utput generators to multiple output 20 I.7 Generator variants 21 Bibliography. 24 Rec. ITU-T K.96 (02/2014) 1 Recommendation ITU-T K.96 Surge protective components: Overview of surge mitigation functions and technologies 1 Scope Surge protective components (SPCs) are used in power, telecommunication
17、 surge protective devices (SPDs) and equipment ports. This Recommendation gives an overview of: surge mitigation functions both non-linear and linear, implementing component technologies and characteristics, and information on the impulse (surge) generators used to test surge protective components (
18、SPCs), surge protective devices (SPDs) and equipment ports. 2 References None. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 avalanche breakdown (of a PN junction) b-IEC 60050-521: Breakdown that is caused by the cumulative multiplica
19、tion of charge carriers in a semi-conductor under the action of a strong electric field, which causes some carriers to gain enough energy to liberate new hole-electron pairs by ionization. 3.1.2 bidirectional transistor b-IEC 60050-521: Transistor which has substantially the same electrical characte
20、ristics when the terminals normally designated as emitter and collector are interchanged. 3.1.3 bipolar junction transistor b-IEC 60050-521: Transistor having at least two junctions and whose functioning depends on both majority carriers and minority carriers. 3.1.4 breakdown (of a reverse-biased PN
21、 junction) b-IEC 60050-521: Phenomenon, the initiation of which is observed as a transition from a state of high dynamic resistance to a state of substantially lower dynamic resistance for increasing magnitude of reverse current. 3.1.5 diode (semiconductor) b-IEC 60050-521: Two-terminal semiconducto
22、r device having an asymmetrical voltage-current characteristic. NOTE Unless otherwise qualified, this term usually means a device with the voltage-current characteristic typical of a single PN junction. 3.1.6 disruptive discharge b-IEC 60050-212: Passage of an electric arc following electric breakdo
23、wn. 3.1.7 disturbance suppression b-IEC 60050-161: Action which reduces or eliminates electromagnetic disturbance. 3.1.8 electromagnetic disturbance b-IEC 60050-161: Any electromagnetic phenomenon which may degrade the performance of a device, equipment or system, or adversely affect living or inert
24、 matter. NOTE An electromagnetic disturbance may be an electromagnetic noise, an unwanted signal or a change in the propagation medium itself. 2 Rec. ITU-T K.96 (02/2014) 3.1.9 filter b-IEEE Std 802.7: Circuit that selects or rejects one or more components of a signal related to frequency. 3.1.10 fo
25、rward direction (of a PN junction) b-IEC 60050-521: Direction of current that results when the P-type semiconductor region is at a positive voltage relative to the N-type region. 3.1.11 insulation b-IEC 60664-2-1: That part of an electrotechnical product which separates the conducting parts at diffe
26、rent electrical potentials. 3.1.12 insulation coordination b-IEC 60664-2-1: Mutual correlation of insulation characteristics of electrical equipment taking into account the expected micro-environment and other influencing stresses. 3.1.13 isolating transformer b-IEC 60065: Transformer with protectiv
27、e separation between the input and output windings. NOTE Isolating transformers can be divided into three groups; mains, switched mod and signal (e.g., Ethernet data). 3.1.14 impulse withstand voltage b-IEC 60664-2-1: Highest peak value of impulse voltage of prescribed form and polarity applied to a
28、 circuit or equipment, which does not cause degradation or result in breakdown or flashover. 3.1.15 low-pass filter b-IEEE Std 1149.6: Electrical network that passes lower frequencies, including DC levels, and attenuates higher frequencies. 3.1.16 overvoltage b-IEC 60664-2-1: Any voltage having a pe
29、ak value exceeding the corresponding peak value of maximum steady-state voltage at normal operating conditions. 3.1.17 punch-through (between two PN junctions) b-IEC 60050-521: Contact between the space charge regions of two PN junctions as a result of widening of one or both of them. 3.1.18 sparkov
30、er b-IEC 60050-212: Disruptive discharge in a gaseous or liquid insulating material. 3.1.19 suppression component b-IEC 60050-161: A component specially designed for disturbance suppression. 3.1.20 Zener breakdown (of a PN junction) b-IEC 60050-521: Breakdown caused by the transition of electrons fr
31、om the valence band to the conduction band due to tunnel action under the influence of a strong electric field in a PN junction. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: NOTE Some term definitions, specifically defined for non-linear voltage limiters,
32、 are inappropriate for the wide range of mitigation functions covered in this Recommendation. The definitions for these terms have been redefined to make them generic. 3.2.1 band-pass filter: Filter that allows passage of a desired range of frequencies and attenuates frequencies outside the desired
33、range. NOTE This definition is based on the definition provided in b-IEEE Std 802.7. 3.2.2 common-mode choke filter: Series in-line transformer used to mitigate common-mode current flow without affecting differential current flow. 3.2.3 common mode conversion: Process by which a differential mode el
34、ectrical signal is produced in response to a common mode electrical signal. NOTE This definition is based on the definition provided in b-IEC 60050-161. 3.2.4 common-mode rejection filter: Filter type, usually a balanced filter that attenuates the signal common to both input lines; that signal is ca
35、lled the common-mode signal. Rec. ITU-T K.96 (02/2014) 3 NOTE This definition is based on the definition provided in b-IEEE Std 1549. 3.2.5 common-mode surge: Surge appearing equally on all conductors of a group at a given location. NOTE 1 The reference point for common-mode surge voltage measuremen
36、t can be a chassis terminal, or a local earth/ground point. NOTE 2 Also known as longitudinal surge or asymmetrical surge. 3.2.6 differential-mode surge: Surge occurring between any two conductors or two groups of conductors at a given location. NOTE 1 The surge source maybe be floating, without a r
37、eference point or connected to reference point, such as a chassis terminal, or a local earth/ground point. NOTE 2 Also known as metallic surge or transverse surge or symmetrical surge or normal surge. 3.2.7 fold-back breakdown (of a bidirectional transistor): Re-entrant breakdown characteristic caus
38、ed by transistor action producing a region of negative dynamic resistance before reverting back to a low positive dynamic resistance condition. NOTE In transistor terms, the initial breakdown is in the BVCBOmode, which changes to the lower voltage BVCEOmode as the breakdown current increases. 3.2.8
39、high-pass filter: Electrical network that passes higher frequencies, attenuates lower frequencies and blocks DC levels. NOTE This definition is based on the definition provided in b-IEEE Std 1149.6. 3.2.9 neutralizing transformers: Transformers that, through a sensing winding connected to local and
40、remote grounds, introduce a series voltage into a signal circuit pair to oppose differences in local and remote ground potentials and induced common mode voltages. 3.2.10 overcurrent: Any current having a peak value exceeding the corresponding peak value of maximum steady-state current at normal ope
41、rating conditions. 3.2.11 power fault: Abnormal fault condition, when the local ac power service is in electrical contact (Power Contact) or is magnetically coupled (Power Induction) to another service. 3.2.12 surge: Temporary disturbance on the conductors of an electrical service caused by an elect
42、rical event not related to the service. NOTE For non-linear SPCs a surge event is defined as an overvoltage or overcurrent or both. 3.2.13 surge protective component (SPC): component specifically included in a device or equipment for the mitigation of the onward propagation of overvoltages or overcu
43、rrents or both. 3.2.14 surge protective device (SPD): Device that mitigates the onward propagation of overvoltages or overcurrents or both. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: BVCBOCollector-Base Breakdown Voltage, Emitter Open BVCEOCollect
44、or-Emitter Breakdown Voltage, Base Open DC Direct Current DSL Digital Subscriber Line ECL Electronic Current Limiter EMC Electromagnetic Compatibility EPR Earth Potential Rise 4 Rec. ITU-T K.96 (02/2014) FFT Fast Fourier Transform GDT Gas Discharge Tube GPR Ground Potential Rise IC Integrated Circui
45、t ICT Information and Communication Technology LCR Inductance, Capacitance Resistance MOV Metal-Oxide Varistor PLC Power Line Communication PTC Positive Temperature Coefficient SPC Surge Protective Component SPD Surge Protective Device 5 Protection or mitigation or suppression? The terms “protection
46、“ and “protective“ are part of the surge protection engineering discipline vocabulary. It should be remembered that these terms imply that, under specified conditions, the surge is reduced to a level below the withstand capability of the following circuit or equipment. However, in the field the inco
47、ming surge parameters are the result of many factors, rather than conforming to the standardized impulses from the generators specified in various standards. Likewise the following circuit or equipment withstand can be unknown. The inclusion of an SPC should reduce the onward level of the incoming s
48、urge, but not necessarily to the withstand level of the “protected“ item and that withstand level may be unknown. For these reasons the ITU-T prefers to use the term “surge mitigation“ (make (something bad) less severe, serious, or painful) instead of “surge protection“. If surge protection is achie
49、ved then it is a successful case of surge mitigation. In b-IEEE Std C62.50 a protection design technique is described for telecom equipment ports that conform to the surge withstand levels of a specific standard. The surge levels applied to the SPC will be greater than that the equipment withstand, otherwise the SPC function is redundant. At these higher levels the surge mitigation should result in an onward open-circuit surge voltage no greater than the equipment surg
