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 K.96 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1 (12/2014) SERIES K: PROTECTION AGAINST INTERFERENCE Surge protective components: Overview of surge mitigation functions and technologies Amendment 1: New Appe
2、ndix II Alternative duration measurement method for 1.2/50-8/20 and 10/700 surge generator impulses Recommendation ITU-T K.96 (2014) Amendment 1 Rec. ITU-T K.96 (2014)/Amd.1 (12/2014) i Recommendation ITU-T K.96 Surge protective components: Overview of surge mitigation functions and technologies Ame
3、ndment 1 New Appendix II Alternative duration measurement method for 1.2/50-8/20 and 10/700 surge generator impulses Summary The time to half value of a double exponential surge, simulating a lightning impulse, is traditionally measured from a virtual zero point to the 50% amplitude decay point of t
4、he waveform, as explained in clause I.3. The time duration of electrostatic discharge (ESD) and electrical fast transient (EFT) impulses is measured as the time for which the impulse exceeds the 50% amplitude level. The time measured from virtual zero will always be longer than the time between the
5、two waveform 50% points. Edition 3 of IEC 61000-4-5 (2014) departs from the traditional lightning surge time to half value measurement by specifying the use of the time between the two waveform 50% points for the 1.2/50-8/20 and 10/700 surge generator waveforms. Amendment 1 to Recommendation ITU-T K
6、.96 introduces Appendix II, which discusses the time value changes caused by the Edition 3 approach and how other standards can be referenced to maintain the tradition measurement method. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T K.96 2014-02-13 5 11.1002/1000/12129 1.
7、1 ITU-T K.96 (2014) Amd. 1 2014-12-19 5 11.1002/1000/12442 _ * 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 (2014)/Amd.
8、1 (12/2014) 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 responsi
9、ble 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, establishes the topics for study by the ITU-
10、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 standards are prepared on a collaborative
11、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 Recommendation may contain certain mandat
12、ory 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 are used to express requirements. The
13、 use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL 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
14、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 received notice of intellectual property
15、, protected 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 2015 All rights reserved. No
16、 part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T K.96 (2014)/Amd.1 (12/2014) iii Table of Contents Page 1) New Appendix II 1 Appendix II Alternative duration measurement method for 1.2/50-8/20 and 10/700 surge generator imp
17、ulses 1 II.1 Introduction 1 II.2 Time to half value measurement 1 II.3 Duration measurement 1 II.4 Comparison of time to half value and duration 2 2) Bibliography . 4 Rec. ITU-T K.96 (2014)/Amd.1 (12/2014) 1 Recommendation ITU-T K.96 Surge protective components: Overview of surge mitigation function
18、s and technologies Amendment 1 New Appendix II Alternative duration measurement method for 1.2/50-8/20 and 10/700 surge generator impulses 1) New Appendix II Add the following appendix after Appendix I: Appendix II Alternative duration measurement method for 1.2/50-8/20 and 10/700 surge generator im
19、pulses (This appendix does not form an integral part of this Recommendation.) II.1 Introduction IEC 61000-4-5 ed3, b-IEC 61000-4-5 ed3, changes the established method of surge waveshape time to half value and names the parameter as duration. An explanation of the changed approach is given in b-Carob
20、bi. This appendix explains the change and possible consequences. II.2 Time to half value measurement Many standards define double exponential waveshape time to half-value for voltage or current or both. b-IEC 60099-9 has a definition covering both voltage and current. virtual time to half-value on t
21、he tail of an impulse, T2: time interval between the virtual origin and the instant when the voltage or current has decreased to half its peak value, expressed in microseconds. II.3 Duration measurement b-IEC 61000-4-5 ed3 has three definitions for the term “duration“; one for voltage and two for cu
22、rrent. 1) duration (surge voltage) Td: time interval between the instant at which the surge voltage rises to 0.5 of its peak value, and then falls to 0.5 of its peak value (TW). Td = TW 2) duration (surge current for 5/320 s) Td: time interval between the instant at which the surge current rises to
23、0.5 of its peak value, and then falls to 0.5 of its peak value (TW). Td = TW 3) duration (surge current for 8/20 s) Td: time interval between the instant at which the surge current rises to 0.5 of its peak value, and then falls to 0.5 of its peak value (TW), multiplied by 1.18. 2 Rec. ITU-T K.96 (20
24、14)/Amd.1 (12/2014) Td = 1.18 TW NOTE For this measurement, an 18 F capacitor is connected in series with the generator output. II.4 Comparison of time to half value and duration b-IEC 61000-4-5 ed3 only covers two generator types; the 1.2/50-8/20 combination wave generator and the 10/700 generator.
25、 II.4.1 Durations type 1 and type 2 When the waveshape front time is 2.5% or less of the time to half value, there is only a small difference between the time to half value and the duration. This condition applies to the 1.2/50 and 10/700 open-circuit voltage waveshapes and the type 1 duration is us
26、ed. Similarly for the 10/700 generator 5/320 short-circuit current waveshape the type 2 duration is used. As an error example, a 1.2/50 waveshape would have a 50 s time to half value (T2) and a duration (Td) of 49.4 s. This is a 1.2% time difference, which will only be significant for generators clo
27、se to the minimum value of T2. II.4.1 Duration type 3 As the 8/20 short-circuit current waveshape has a front time that is 40% of the time to half value, serious discrepancies would arise if just 50% amplitude time (TW) was used. For example a 8/20 waveshape would have a TW value of about 17 s. This
28、 is why the type 3 duration multiples the TW value by factor of 1.18. Figure II.1 shows this condition. Figure II.1 Comparison of time to half value, T2, and duration, Td Figure II.1 uses a timescale of t/(LC)0.5, where L is the series inductance and C is the energy storage capacitor of a simple RLC
29、 combination wave generator circuit. The actual current waveshape will depend on the resistive damping factor, k, of the LC circuit, see Figure II.2. Normalised Time - t/(LC)0.50 1 2 3 4 5Normalised Amplitude-0.3-0.2-0.10.10.20.30.40.60.70.80.90.00.51.0-1TWTd= 1.18xTWVirtualoriginDurationTime tohalf
30、 value T2Rec. ITU-T K.96 (2014)/Amd.1 (12/2014) 3 Figure II.2 Short-circuit current waveshape variation with damping factor k To meet the requirements of an 8/20 waveshape, the k value needs to be between 0.35 (30% undershoot condition) and 0.95 (no undershoot). The T2/Td factor varies with k as sho
31、wn in Figure II.3. Figure II.3 T2/TW ratio versus the damping factor k Figure II.3 shows that the 1.18 factor is optimized for a k value of 0.4 which results in a time to half value to front time ratio of 2.6 (impulse shape range of 6.4/16.4 to 9.2/24). At k values of 0.5 or above and front times le
32、ss than 8.4 s, the 1.18 factor can give durations (Td) longer than T2 and the 24 s limit of the 8/20 waveshape. This could cause some generator compliant to IEC 61000-4-5 ed2 to be non-compliant to b-IEC 61000-4-5 ed3. IEC 61000-4-5 ed2 has been withdrawn, those wishing to continue to measure in the
33、 established way, as embodied in ed2, could reference back to the components that established the combination wave generator; the 1.2/50 insulation voltage test impulse and the 8/20 arrester current impulse. Three elements are needed to create a 1.2/50-8/20 combination generator definition. 1 The 1.
34、2/50 open-circuit voltage waveshape shall be according to b-IEC 60060-1 having a front time of 1.2 s 30% and a time to half value of 50 s 20%. 2 The 8/20 short-circuit current waveshape shall be according to b-IEC 62475 having a front time of 8 s 20% and a time to half value of 20 s 20%. The opposit
35、e polarity current undershoot shall not exceed 30% of the peak current. 3 The ratio of peak open-circuit voltage to short-circuit current shall be 2 10%. Normalised Time - t/(LC)0.50 1 2 3 4 5 6 7 8Normalised Amplitude-0.4-0.3-0.2-0.10.10.20.30.40.60.70.80.9-0.50.00.51.0k = 0.25 k = 0.35 k = 0.45 k
36、= 0.55 k = 0.65 k = 0.75 k = 0.85 k = 0.95 k circuit damping factor0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95T2/TW1.101.111.121.131.141.151.161.171.181.191.201.211.22Edition 3T2/TWFactor4 Rec. ITU-T K.96 (2014)/Amd.1 (12/2014) 2) Bibliography Add the following entries to the Bibliography: b-IEC 60099-9
37、 IEC 60099-9 (2014-06), Surge arresters Part 4: Metal-oxide surge arresters without gaps for a.c. systems. b-IEC 61000-4-5 ed3 IEC 61000-4-5 ed3.0 (2014-05), Electromagnetic compatibility (EMC) Part 4-5: Testing and measurement techniques - Surge immunity test. b-Carobbi C. F. M. Carobbi and A. Bonc
38、i, Elementary and Ideal Equivalent Circuit Model of the 1.2/50 8/20 s Combination Wave Generator, IEEE Electromagnetic Compatibility Magazine, Volume 2, Quarter 4, 2013. Printed in Switzerland Geneva, 2015 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General ta
39、riff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services
40、digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, includ
41、ing TMN and network maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Terminals and subjective and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission
42、 Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
