1、BRITISH STANDARD BS 6662:1985 IEC 816:1984 Guide to Methods of measurement of short duration transients on low voltage power and signal lines UDC 621.317.7:621.391.82.015.3:621.3.05.027.2BS6662:1985 This British Standard, having been prepared under the directionof the General Electrotechnical Engine
2、ering Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 31 December 1985 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference GEL/111 Draft for comment 83/26728 DC ISBN 0 580 14801 7 Committees responsible f
3、or this British Standard The preparation of this British Standard was entrusted by the General Electrotechnical Engineering Standards Committee(GEL/-) to Technical Committee GEL/111 upon which the following bodies were represented: Association of Manufacturers of Domestic Electrical Appliances BEAMA
4、 Ltd. British Broadcasting Corporation British Lighting Association for the Preparation of Standards (Britlaps) British Radio and Electronic Equipment Manufactures Association British Telecommunications plc Business Equipment Trade Association Department of Health and Social Security Department of T
5、rade and Industry (Radio Regulatory Division) Electrical Installation Equipment Manufacturers Association (BEAMA Ltd.) Electricity Supply Industry in England and Wales Electronic Engineering Association Engineering Equipment and Materials Users” Association ERA Technology Ltd. GAMBICA (BEAMA Ltd.) I
6、ndependent Broadcasting Authority Induction and Dielectric Heating Manufacturers” Association Institution of Electronic and Radio Engineers Lighting Industry Federation Ltd. Ministry of Defence National Air Traffic Services Society of Motor Manufacturers and Traders Limited United Kingdom Atomic Ene
7、rgy Authority The following bodies were also represented in the drafting of the standard, through sub-committees and panels: Association of Control Manufacturers TACMA (BEAMA Ltd.) British Steel Corporation Department of Trade and Industry (Electronics Applications Division) Institution of Electrica
8、l Engineers Amendments issued since publication Amd. No. Date of issue CommentsBS 6662:1985 BSI 01-2000 i Contents Page Committees responsible Inside front cover National foreword ii Introduction 1 1 Scope 1 2 Characteristics of transients 1 2.1 Environment-produced transients 1 2.2 Appliance-produc
9、ed transients 1 2.3 Parameters to be measured 2 3 Characteristics of mechanisms of coupling between transient sources and potentially susceptible devices 3 3.1 Propagation modes 4 4 Susceptibility/Immunity 5 4.1 Damage effects 5 4.2 Malfunction effects 5 5 Instrumentation 6 5.1 Obtaining statistical
10、 data on parameters of transients 6 5.2 Transient counter 7 5.3 Peak voltmeter 7 5.4 Other parameters 7 5.5 Waveform recording and analysis 7 5.6 Transient energy measurements 10 5.7 Frequency domain measurement 11 5.8 Special inexpensive devices 13 6 Measurement techniques 13 6.1 Measurement of con
11、ducted transients 13 6.2 Measurement of radiated transients 18 Appendix A Method for measuring transient conducted emissions 33 Appendix B Equipment input impedance 35 Appendix C Example of a monitoring probe 37 Bibliography and references 38 Figure 1 Typical parameters of a transient 19 Figure 2 Ex
12、ample of a transient disturbance 20 Figure 3 Propagation modes on power distribution systems 21 Figure 4 Relation between phase, CM and DM open-circuit voltages 22 Figure 5 Power line measured impedance for United States of America andEurope 23 Figure 6a) Illustration of the various propagation tran
13、sient paths fordifferentconditions 24 Figure 6b) The insertion loss for the various paths described in Figure 6a) 25 Figure 6c) Current probe technique for signal injection 26 Figure 7 Relation between parts of measuring instruments 27 Figure 8 Occurrence of aliasing 27 Figure 9 FFT-spectrum and Fou
14、rier integral of a trapezoidal pulse 28 Figure 10 Quantization level of the ADC vs. time 28 Figure 11 Thermistor bridge and 10 amplifier 29BS 6662:1985 ii BSI 01-2000 Page Figure 12 Test arrangement for the measurement of conducted transients 29 Figure 13 Physical layout of the probe testing unit 30
15、 Figure 14 Circuit diagram of the probe testing unit 30 Figure 15 Physical layout of the high impedance monitoring probe 31 Figure 16 Circuit diagram of the high impedance monitoring probe 32 Figure A.1 Measuring set (example) 34 Figure B.1 35 Figure B.2 36 Figure B.3 36 Figure B.4 37 Table A.I 33 P
16、ublications referred to Inside back coverBS 6662:1985 BSI 01-2000 iii National foreword This British Standard has been prepared under the direction of the General Electrotechnical Engineering Standards Committee. It is identical with IEC Publication 816:1984 “Guide on methods of measurement of short
17、 duration transients on low voltage power and signal lines” published by the International Electrotechnical Commission (IEC). Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology an
18、d certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker in the figures. In British Standards it is current practice to use a full point on the baseline as a decimal marker. Cross-referen
19、ces. The Technical Committee has reviewed the provisions of the Special Committee on Radio Interference (CISPR) of the IEC, CISPRPublication16 “CISPR specification for radio interference measuring apparatus and measurement methods”, to which reference is made in the text, and has decided that they a
20、re acceptable for use in conjunction with this standard. A related British Standard to CISPR Publication 16 is BS 727:1983 “Specification for radio-interference measuring apparatus”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards
21、 are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to 38, an inside back cover and a back cover. This standar
22、d has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS 6662:1985 BSI 01-2000 1 Introduction Transients appearing on power and signal lines are capable of producing a variety of effects rangi
23、ng from minor equipment performance degradation to catastrophic insulation breakdown. They have a wide variety of waveforms, which depend upon the mechanism of generation. Furthermore, those that originate from switching a.c. power on and off will have a form that depends upon the exact moment in th
24、e power cycle at which switching takes place, but in addition can have very complicated micro (detailed) and macro (overall) waveform characteristics. Because of this variety and the frequently random time of occurrence, there is considerable difficulty in making a suitable measurement of a transien
25、t. The advent of new technologies in device design and manufacture has increased concern for identifying more precisely the effects of transients. In particular, a solid-state device can be susceptible even to an overvoltage of very short (nanosecond) time duration. Furthermore, because of variation
26、s in the waveforms, to have a precise measurement of any given transient would require the measurement of a large number of parameters. Even if one measures the exact waveform of a transient, for control purposes, one must then describe the transient with a finite number of parameter values. The cho
27、ice of these parameters and their expected range of values is still a matter of some speculation, and the proper method of measurement is still considered by some to be an open question. Modern types of test equipment provide measurement capabilities not available previously, but they must be used w
28、ith particular care. Accordingly, there is a need for well-defined and accepted methods of measuring transients for two major reasons, namely so that: a) measurements made by different laboratories may be compared; b) meaningful limits may be placed on transients generated by particular types of equ
29、ipment and on the susceptibility of particular equipment to transients. This guide has been prepared to assist in meeting these requirements. Note that in this guide the concern is with transient phenomena which are not line-frequency related and are of duration no greater than 40 ms. It is also not
30、 concerned with sustained voltage changes or fluctuations. 1 Scope This report is intended to give guidance on methods of measurement of short duration transients on low voltage power and signal lines. 2 Characteristics of transients Transients may be classified according to their origin as follows:
31、 a) those produced by the environment, that is to say, by lightning; b) those produced by electrical switching or faults; c) those produced internally within the circuits of particular equipment. 2.1 Environment-produced transients These transients arise from lightning and are most severe on overhea
32、d and unscreened cable sections. At the point closest to the point at which the transient is generated, the rise time can be short and the amplitude high. The rise time and fall time can be considerably lengthened and the amplitude reduced as the transient propagates along the network. Typically, su
33、ch transients have rise times of the order of microseconds and fall times from504s to 50 ms and may be oscillatory. The effects on inner conductors are reduced in the case of screened cables and cables buried in areas of low ground resistivity. 2.2 Appliance-produced transients Transients produced b
34、y appliances arise from three basic causes: a) the operation of a mechanical or semiconductor switch; b) turn-on currents associated with the saturation properties of an iron-core transformer or starting currents in motors; c) faults within equipment.BS 6662:1985 2 BSI 01-2000 The transient produced
35、 by a switch or fault can range from a simple surge or dip (sag) to a very complex waveform caused by repeated “restriking” of an arc as the contacts of a mechanical switch separate. The most serious transients usually arise as a result of breaking an inductive circuit, for example, the blowing of a
36、 fuse. In many cases, special techniques, such as placing capacitors across the contacts, will reduce the magnitude of the transients generated, and in other cases suppression can be obtained by the use of semiconductor devices. The transients can have rise times of the order of a few nanoseconds in
37、 the immediate vicinity of the switch, that is to say, within a fraction of a metre; however, at distances of several metres from the switch, the rise time will be considerably increased due to attenuation of the line of the higher frequency components. Switching of transformers produces transients
38、which may be of the order of several times the peak line voltage but will have rise times of the order of tens of microseconds. 2.3 Parameters to be measured Because of the complex and variable nature of transients, it is difficult to specify which parameters should be measured. Under such circumsta
39、nces, it is useful to examine the susceptibility characteristics of the equipment under consideration and to divide these into several categories in order to determine the parameters to be measured (see Clause 4): a) those which are susceptible to a restricted band of frequencies, such as radio or c
40、arrier frequency receivers; b) those which are susceptible to a broad band of low radio frequencies (for example, a mains rectifier). For such devices the peak voltage is usually the critical parameter; but energy may also be an important parameter; c) those which are susceptible to a broad band of
41、frequencies in the higher frequency bands. The critical quantity is the rate of rise of the pulse. Digital equipment is often susceptible to this parameter, and destruction of devices may also occur. Some general measurement capabilities can be desirable but one may not be able to measure all parame
42、ters with a single instrument. For convenience, these parameters may be classified according to whether they give information in the time or frequency domains. Figure 1, page 19, illustrates the possible complex nature of a typical transient and some of the time domain parameters that may be used to
43、 describe it. In addition, effective pulse strength (voltage time) and energy content may be significant. The most common frequency domain parameter used to describe a transient is the spectrum amplitude. The frequency vs. phase characteristic may also be important but is not usually measured becaus
44、e of difficulties in both measurement and use of the data. Where the interference is discontinuous in nature, time weighting techniques such as those used in the C.I.S.P.R. instrument may also be applied. The unweighted component is of interest in any case. 2.3.1 Relation between time domain and fre
45、quency domain parameters Figure 2a), page 20, shows a representative waveform of one type of transient disturbance produced during a switching-off operation of a 220 V auxiliary conductor. Figure 2b), page 20, shows a spectrum amplitude representation of such a waveform. The relationship between the
46、 spectrum amplitude plot and the time domain waveform is best explained by comparing the relevant characteristics for a trapezoidal pulse. The spectrum amplitude of a symmetrical trapezoidal pulse with the mean pulse time T is, in the frequency range below f = 1/;T, independent of frequency (this po
47、rtion of the spectrum amplitude curve is parallel to the abscissa) and has a magnitude equal to the amplitude-time area of the pulse. Above the frequency f = 1/; T the envelope of the spectrum varies as 1/f. If the trapezoidal pulse has rise and fall times t, the envelope of the spectrum amplitude a
48、bove the frequency 1/;t varies as 1/f 2 . Note that on Figure 2b) the abscissa is marked in megahertz on a logarithmic scale and the ordinate is given in decibels with respect to 1 4V s . (1 4V scorresponds to 10 64V in 1 MHz.) The spectrum amplitude representation can be calculated using standard F
49、ourier integral techniques. When the pulses are repeated at regular intervals, a discrete spectrum rather than a continuous spectrum is obtained. In that case, a representation corresponding to Figure 2b) can be used, but the curve shown corresponds to the amplitude of the discrete components (envelope curve) which are spaced on the frequency scale at a distance corresponding to the repetition rate. Accordingly, the following interpretation, can be placed on Figure 2b), page 20: a) the low-frequency or fiat portion of the curve is a leve
