1、II 48b25L 0681530 88L m INTERNATIONAL TELECOMMUNICATION UNION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITEE DIRECTIVES concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines VOLUME VIII PROTECTIVE DEVICES
2、 Geneva 1989 m 4862593 Ob83533 738 m INTERNATIONAL TELECOMMUNICATION UNION CCITT THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITEE DIRECTIVES concerning the protection of telecommunication lines against harmful effects from electric power and electrified railway lines VOLUME VIII PROTE
3、CTIVE DEVICES Geneva 1989 ISBN 92-61 -04091 -8 W 4862593 0683532 b54 0 I.T.U. 9 48b2591 Obl533 590 PREFACE The rapid development of new technologies in telecommunications, electric power transmission and distrib- ution, and electric railway systems has made the earlier issue of the Directives (1960
4、edition) out-of-date and this former issue is therefore being replaced completely. The present Directives (1988 edition) have been established by the International Telegraph and Telephone Consultative Committee (CCIW to give clear advice on how adverse electromagnetic effects on telecommunications l
5、ines from nearby electric power or electric railway installations may be minimized. The Directives have been based on the latest information that is available. nie new Directives have been prepared in close cooperation with the following international organizations : - the Intemational Union of Rail
6、ways (UIC) - the International Conference on Large High Voltage Electric Systems (CIGRE). Representatives from these organizations have participated in preparation of the text of the Directives. The two organizations support the underlying principles from which these texts have been derived, and the
7、 guidelines in the Directives which have been given. Such guidelines normally relate to general cases which are described. It is left to national organizations to establish more detailed regulations which apply to particular cases. The new Directives are divided into a series of separate volumes, ea
8、ch dealing with a particular part of the complete subject. Each volume can be used independently. Modem calculation methods which are suitable for compu- ter techniques have been incorporated. Numerical values are used to define desirable limits which should be followed when the recommended technica
9、l measures are taken. In general, it should not be necessary to exceed these limits, although some special cases may arise where it is either uneconomical or impractical to do so (e.g. in narrow valleys). In such cases, mutual agree- ment based on the principles set out in the Directives should be r
10、eached. Guidance on administration, economic and particularly legislation matters have been omitted deliberately since they are considered to be outside the technical scope of the advice given in the new Directives. In consequence, the rules of procedure which should be followed by telecommunication
11、s operators, and electric power and electric rail- way authorities have not been covered. Nevertheless, the three international organizations which have worked together to produce the new Direc- tives, CCITT?, UIC and CIGRE, recommend that : ?Telecommunications, electric power and electric railway a
12、uthorities should work together closely and fol- low the new Directives when seeking solutions to mutual problems. The solutions chosen should be those most accept- able and economical overall, and should not confer undue advantages to any participant. We, the undersigned, representing the three org
13、anizations, CCIT, UIC and CIGRE, support the work done jointly on behalf of our organizations in producing these Directives. We recommend these Directives to members of CCIIT, UIC and CIGRE who seek solutions to mutual disturbance problems.? Th. IRMER Director ofrhe CCRT J. BOULEY Secretary-General
14、of UIC G. LEROY Secreta y-General of CIGRE 40b25911 Ob811534 427 TABLE OF CONTENTS Page CHAPTER 1 . INTRODUCTION . 1 Aim and scope of the DUectiv es 1 Structure of the Directives . 2 Content of individual volumes . 2 Use of the Directives 3 When studying coupling processes in general . 3 1.1 1.2 1.2
15、.1 1.2.2 1.2.2.1 1.2.2.2 1.2.2.3 When establishing standards or similar regulations . 3 When dealing with danger and disturbance problems in practice . 3 Purpose of the volume . 5 1.3 CHmR 2 - PARALLEL DEVICES FOR OVERVOLTAGE PROTECTION . 7 2.1 2.2 Spark-gap type devices 7 2.1.1 2.1.2 Carbons 9 2.1.
16、3 Air gaps . 10 Gas discharge tubes (GDTs) . 7 Semi-conductor devices 11 2.2.1 Voltage-dependent resistors (VDR or varistors) 11 2.2.2 Zener diodes 12 2.2.3 Foldback diodes . 13 2.2.4 Di odes 13 2.2.5 2.2.6 2.2.7 Complex devices 14 Thyristors (silicon controlled rectifiers, Sas) . 14 Solid-state ove
17、r-voltage protectors . 14 CHAPTER 3 . SERIES DEVICES FOR OVERCURRENT PROTECTION 15 3.1 Fu ses . 15 3.2 Heat coils 16 3.3 Positive temperature coefficient (PTC) resistors 18 3.4 Fuse cab1 es 20 3.5 Impedance (Resistors or Inductors) . 21 Previous page is blank . Volume VIII . Table of contents V 48b2
18、59l1 0681535 3b3 CHAPTER 4 . PROTECTION DEVICES WCH DO NOT PRODUCE INTERRUPTION OF SERVI CE 23 4.1 Lme transformem 23 4.2 Isolation transformers 23 4.3 optically coupled isola (opto-couplers) . 25 Single component opto-couplers 26 High voltage opto-couplers 26 4.5 Reduction transfomers . 30 4.6 Drai
19、nage coils . 30 Coupling coils (equalizing coils) . 31 Active reduction systems . 32 4.3.1 4.3.2 4.4 Neutralizing transfomers 26 4.7 4.8 VI Volume VIII . Table of contents CHAPTER1 INTRODUCTION 1.1 Aim and scope of the Directives The present Directives supersede the 1963 edition approved by the 2nd
20、Plenary Assembly of CCI“ in New Delhi 1%0. The 1963 Directives were amended in 1965, 1974, 1978 and 1982. They provided a comprehensive description of electromagnetic effects due to the close proximity of telecommunication lines to power and electrified railway systems, containing regularly updated
21、findings in this field and reflecting the current state of the art. Analyses have shown, however, that in spite of these advantages, the 1%3 Directives are not used as widely as expected. The main reasons for this are believed to be that the 1963 Directives form a very bulky book which is hard to ha
22、ndle and in which theoretical considerations tend to prevail over practical advice. Calculation methods and the related models were developed before modem computer technology was available. Since the 1963 Directives reflected the principal arrangements which appeared in the original first issue in 1
23、925, many cross-references became necessary as new clauses were added. In consequence, the VIIth Plenary Assembly of CCITT in Geneva 1980 decided to revise the 1963 Directives completely and entrusted Study Group V with the task of producing new Directives for publication in 1988. The new Directives
24、 are intended to meet a number of requirements, particularly those sought by engineers in the field. Nevertheless, the valuable background advice contained in the 1963 Directives is retained and even ex- panded wherever relevant. As a result, the new Directives should be useful: - to practising engi
25、neers who seek guidelines on how to deal with danger and disturbance problems; - to scientists and researchers who need a reference book with the most recent findings; - to students who require a textbook with which to become acquainted with electromagnetic coupling phenomena; - to Administrations w
26、hich need to have a basis to form national regulations and standards. The new Directives have been prepared as a result of close collaboration between many members of CCITT, CIGRE and the UIC. They therefore describe technical methods for solving mutual problems which are recognized by these intemat
27、ional organizations and which should facilitate coordination between member organizations in user coun- tries. The principal object of the new Directives is to describe ways in which adverse effects from power transmission and distribution lines or from electrified railway lines onto telecommunicati
28、on lines can be reduced or avoided. Such effects may result in danger to personnel, damage to telecommunication equipment, deterioration of telecommunication transmission quality or to disturbance of signalling. Although the advice given in the new Directives has been described for public telecommun
29、ication networks, the basic principles have a more general application, and owners of other networks should decide whether they can be adapted to their own needs. Volume VIII - Chap. 1 1 M 4862571 0683537 L3b E 1.2 Struckre of the Directives 1.2.1 Content of individual volumes The new Directives are
30、 divided into 9 volumes, each dealing with a sepate part of the overall subject matter. The series is made up as follows: Volume I “Design, consmiction and operational principles of telecommunication, power and electrified railway facilities“ describes these systems and shows why conditions for thei
31、r mutual coexistence must be established. Volume II “Calculating induced voltages and currents in practical caw“ describes the methods for evaluating voltages and cmnts resulting from capacitive, inductive and conductive coupling in a variety of commonly-encountered situations. Volume III “Capacitiv
32、e, inductive and conductive coupling: physical theory and calculation methods“ gives an account of the physical laws governing the relevant phenomena together with mathematical models, and introduces a precise calculation method to evaluate voltages and currents resulting from couplings. Volume IV “
33、Inducing currents and voltages in electrified railway systems“ describes traction systems using d.c. and a.c. at various frequencies (16 2/3 Hz, 50 Hz, 60 Hz etc.) in normal operation and under fault conditions. Volume V “Inducing currents and voltages in power transmission and distribution systems“
34、 describes unbalanced and balanced power systems in normal operation and under fault conditions. Volume VI “Danger and disturbance“ considers the risk to both equipment and people. Volume VU “hotective measures and safety precautions“ describes methods which are commonly used to ensure satisfactory
35、working and operating conditions. Volume VI11 “Ptotective devices“ gives the latest information on devices which may be used to improve safety standards or reduce disturbance of telecommunication systems. Volume IX “Testing methods and measuring apparatus“ describes the methods and apparatus used to
36、 determine parameters required for coupling calculations, and to verify the satisfactory operation of protective measures. In addition it deals with testing methods taking into account modem practices in other fields of electromagnetic compatibility (e.g. lightning, high frequency disturbances). The
37、 volumes overlap to some extent deliberately. This limits the need to consult several volumes simultaneously when resolving practical problems. Calculation methods for evaluating voltages and currents induced into lines are given in both Volumes II and III. In Volume II simplified formulae are given
38、 for each type of coupling with graphs and data for stepby-step calculation. The method covers the usual cases which arise in practice and requires access only to calculators or small computers. It is useful to those seeking a simple procedure where some approximations have to be made. In Volume III
39、, a rigorous calculation method is given, strictly associated with the theory of coupling which is also treated in the volume. The method deals with a wide range of situations and assumes that access is available to aequate computing facilities. The volume is intended to be used by those who require
40、 a pise evaluation of the coupling results. 2 Volume VIII - Chap, 1 4862591 0681538 O72 = 1.2.2 Use of the Directives 1.2.2.1 When stuying coupling processes in general - For a broad understanding of telecommunication, power and electrifie railway facilities and their mutual coupling effects, consul
41、t Volume I. - For further information on inducing installations in power or electrified railway systems, consult Volume IV (railway systems) or Volume V (power systems). - For detailed study of coupling phenomena and calculation methods, consult Volumes II and III. - To understand the effects of ind
42、uced voltages and currents, Le. danger and disturbance, and the limiting values which are recommended, consult Volume VI. - For advice on protective components or complex protective devices, consult Volume VIII. - For information on relevant testing and measuring techniques, consult Volume IX. 1.2.2
43、.2 When establishing standards or similar regulations - For limiting values of induced voltages and currents, consult Volume VI. - For estimating induced voltages and currents using simplified calculations, consult Volume II. - For precise calculation of induced voltages and currents, consult Volume
44、 III. - To select appropriate protective measures, consult Volume VIL 1.2.2.3 When dealing with danger and disturbance problems in practice - Identify the telecommunication, power and electrified railway lines involved and ensure they are described in adequate detail. - Compare the operational and f
45、ault conditions in the inducing systems with the actual inducing voltages and currents by consulting Volume IV (railway systems) or Volume V (power systems). - Determine the electrical and geometrical parameters needed for calculations in Volume II or Volume III using numerical values that are known
46、. - To measure parameters which are not known, consult Volume IX. - To estimate the induced voltages or currents using simple calculation methods, consult Volume II. - To calculate induced voltages and currents precisely, consult Volume III. - To decide whether the predicted induced voltages and cur
47、rents are acceptable, consult Volume VI. - To select suitable protective measures, consult Volume VIL These steps are illustrated in the flowchart in Figure l/l. Volume VIII - Chap. 1 3 START 7 Identify power or electrified railways and telecommunication facilities involved i- Determine electric and
48、 geometrical paramaters required to estimate the effects Calculate induced voltages and currents c Stipulate protective measures A Yes levels exceeded ? FIGURE 111 Flowchart to be followed whem dealing with danger and disturbpace problems i p larger ones have been used for the protection of terminai
49、 equipment on telex lines. They are also used for protection on power circuits where their robustness and ability to extinguish after a voltage surge are important features. Some complex devices (see 8 2.2.5) incorporate VDRS. USERS - Telecommunications Administration, France Deutsche Bundespost, Federal Republic of Germany. FURTHER INFORMATION - Users as above. 2.2.2 Zenerdiodes Zener diodes are produced with a large range of characteristics and are widely used as elements of electronic circuits (not necessarily for protection). They are diodes which, in the reverse direction,
