1、BRITISH STANDARD BS 7484:1991 IEC 1000-2-1: 1990 Guide to Electromagnetic environment for low-frequency conducted disturbances and signalling in public power supply systemsBS7484:1991 This British Standard, having been prepared under the directionof the General Electrotechnical Standards PolicyCommi
2、ttee, was publishedunder the authority ofthe Standards Board and comesinto effect on 31October1991 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference GEL/110 Special announcement in BSINews September 1991 ISBN 0 580 20043 4 Committees responsible for th
3、is British Standard The preparation of this British Standard was entrusted by the General Electrotechnical Standards Policy Committee (GEL/-) to Technical Committee GEL/110, upon which the following bodies were represented: Association of Control Manufacturers (TACMA) (BEAMA Ltd.) Association of Man
4、ufacturers of Domestic Electrical Appliances Automated Material Handling Systems Association BEAMA Interactive and Mains Systems Association (BIMSA) BEAMA Ltd. British Lighting Association for the Preparation of Standards (Britlaps) British Radio and Electronic Equipment Manufacturers Association Br
5、itish Telecommunications plc Department of Health Department of Transport EEA (the Association of Electronics, Telecommunications and Business Equipment Industries) ERA Technology Ltd. Electrical Installation Equipment Manufacturers Association (BEAMA Ltd.) Electricity Supply Industry in United King
6、dom Electro Medical Trade Association Limited Electronic Components Industry Federation Engineering Equipment and Materials Users Association GAMBICA (BEAMA Ltd.) Health and Safety Executive Induction and Dielectric Heating Manufacturers Association Institution of Electrical Engineers Lighting Indus
7、try Federation Ltd. Ministry of Defence National Air Traffic Services National Telecommunications Ltd. National Transcommunications Ltd. Radiocommunications Agency Rotating Electrical Machines Association (BEAMA Ltd.) Society of British Gas Industries Society of Motor Manufacturers and Traders Limit
8、ed Sound and Communication Industries Federation Transmission and Distribution Association (BEAMA Ltd.) United Kingdom Atomic Energy Authority The following body was also represented in the drafting of the standard, through subcommittees and panels: British Steel plc Amendments issued since publicat
9、ion Amd. No. Date CommentsBS7484:1991 BSI 09-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Purpose of specifying electromagnetic compatibility levels 2 5 Harmonics 3 6 Interharmonics 5 7 Voltage fluctuations 7
10、 8 Voltage dips and short supply interruptions 8 9 Voltage unbalance 9 10 Mains signalling 10 11 Power frequency variation 11 12 D.C. components 11 Figure 1 Coordination between the disturbance level in the environment, the compatibility level, the immunity level, the susceptibility level 12 Figure
11、2 Superposition of harmonic currents 13 Figure 3 Sinusoidal voltage fluctuation of 10 Hz frequency 13 Figure 4 Illustration of peak voltage changes 14 Figure 5 Some illustrations of voltage fluctuation waveforms 15 Figure 6 Illustration of a voltage dip (%U 1 ) or a voltage interruption (%U 2= 100%)
12、 16 Publication(s) referred to Inside back coverBS7484:1991 ii BSI 09-1999 National foreword This British Standard has been prepared under the direction of the General Electrotechnical Standards Policy Committee. It is identical with IEC1000-2-1:1990 “Electromagnetic compatibility (EMC)” Part 2 “Env
13、ironment” Section 1 “Description of the environment Electromagnetic environment for low-frequency conducted disturbances and signalling in public power supply systems” which has the status of a Technical Report and is published by the International Electrotechnical Commission (IEC). IEC 1000 will be
14、 published in separate Parts in accordance with the following structure. Part 1: General; General considerations (introduction, fundamental principles) Definitions, terminology Part 2: Environment; Description of the environment Classification of the environment Compatibility levels Part 3: Limits;
15、Emission limits Immunity limits (in so far as they do not fall under the responsibility of the product committees) Part 4: Testing and measurement techniques; Measurement techniques Testing techniques Part 5: Installation and mitigation guidelines; Installation guidelines Mitigation methods and devi
16、ces Part 9: Miscellaneous. Each Part will be subdivided into Sections each of which may be published as either a standard or a Technical Report. The Technical Committee has reviewed the provisions of IEC146:1985, to which reference is made in the text, and has decided that they are acceptable for us
17、e in conjunction with this standard. A related standard to IEC146 is BS4417. IEC38:1983 has been adopted by CENELEC as harmonized document HD472 S1:1989 which incorporates a deviation for the low voltage public electricity supply systems in use in the UK which are 240V and415V. Cross-references Inte
18、rnational Standard Corresponding British Standard IEC 50 (161):1990 BS 4727 Glossary of electrotechnical, power, telecommunication, electronics, lighting and colour terms Part 1 Terms common to power, telecommunications and electronics Group 09:1991 Electromagnetic compatibility (Identical) IEC 555-
19、3:1982 BS 5406 Disturbances in supply systems caused by household appliances and similar electrical equipment Part 3:1988 Specification of voltage fluctuations (Identical) IEC 868:1986 BS 6796:1986 Specification for flickermeters (Identical)BS7484:1991 BSI 09-1999 iii The provisions of IEC1000-2-2 a
20、re currently being reviewed by CENELEC with a view to determining what common modifications are required before adoption as a European Standard (EN). This EN, when ratified, will be numbered EN61000-2-2 and will be implemented as BSEN61000-2-2. A British Standard does not purport to include all the
21、necessary provisions of a contract. Users of British Standards 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, pa
22、ges1to 16, an inside back cover and a back cover. This standard 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 blankBS7484:1991 BSI 09-1999 1 1 Scope This section of IEC1000-2 is concerned wit
23、h conducted disturbances in the frequency range up to10kHz with an extension for mains signalling systems. Separate sections give numerical compatibility levels for different system voltage levels. This section does not deal with the application of compatibility levels to assess, for example, the pe
24、rmissible interference emission from specific items of equipment or installations, because other system parameters, such as its impedance as a function of frequency, have also to be considered. Furthermore, it does not prejudge the specification of immunity levels by the product committees but merel
25、y provides a guide. The disturbance phenomena considered are: harmonics; inter-harmonics; voltage fluctuations; voltage dips and short supply interruptions; voltage unbalance; mains signalling; power frequency variation; d.c. components. The object of this section is to give information on the vario
26、us types of disturbances that can be expected on public power supply systems. It is a reference document for those associated parts that give values of compatibility level. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions
27、of this section of IEC1000-2. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this section of IEC1000-2 are encouraged to investigate the possibility of applying the most recent editions of the standards indicat
28、ed below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 38:1983, IEC standard voltages. IEC 50(161):1990, International Electrotechnical Vocabulary (IEV), Chapter 161: Electromagnetic Compatibility. (Under consideration.). IEC 146:1985, Semiconductor conve
29、rtors. Second impression 1985 incorporating: Supplement 146A (1974) and Amendment No. 1 (1975). IEC 555-3:1982, Disturbances in supply systems caused by household appliances and similar electrical equipment. Part 3: Voltage fluctuations. IEC 868:1986, Flickermeter. Functional and design specificatio
30、ns. IEC 1000-2-2:1990, Electromagnetic compatibility (EMC). Part 2: Environment. Section 2: Compatibility levels for low-frequency conducted disturbances and signalling in public low-voltage power supply systems. 3 Definitions The definitions are taken from IEC 50(161): International Electrotechnica
31、l Vocabulary (IEV), Chapter 161: Electromagnetic compatibility. The relevant basic definitions are: 3.1 electromagnetic compatibility; EMC (abbreviation) (IEV 161-01-07) the ability of an equipment or system to function satisfactorily in its electromagnetic environment without introducing intolerabl
32、e electromagnetic disturbances to anything in that environment 3.2 (electromagnetic) compatibility level (IEV 161-03-10) the specified maximum electromagnetic disturbance level expected to be impressed on a device, equipment or system operated in particular conditionsBS7484:1991 2 BSI 09-1999 NOTEIn
33、 practice the electromagnetic compatibility level is not an absolute maximum level, but may be exceeded with a small probability. 3.3 electromagnetic disturbance (IEV 161-01-05) any electromagnetic phenomenon which may degrade the performance of a device, equipment or system, or adversely affect liv
34、ing or inert matter NOTEAn electromagnetic disturbance may be an electromagnetic noise, an unwanted signal or a change in the propagation medium itself. 3.4 disturbance level (not defined in IEV 161) the value of a given electromagnetic disturbance, measured in a specified way 3.5 limit of disturban
35、ce (IEV 161-03-08) the maximum permissible electromagnetic disturbance level, as measured in a specified way 3.6 immunity level (IEV 161-03-14) the maximum level of a given electromagnetic disturbance incident on a particular device, equipment or system for which it remains capable of operating at a
36、 required degree of performance 3.7 (Electromagnetic) susceptibility (IEV 161-01-21) the inability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance NOTESusceptibility is a lack of immunity. 4 Purpose of specifying electromagnetic compa
37、tibility levels NOTEAn interpretation of the basic definitions for practical application in IEC is in preparation. The main results are considered in this clause. From the definition of electromagnetic compatibility level it can be seen that it is a reference value by means of which the disturbance
38、level on the system and the immunity level for various equipment types can be coordinated. For practical purposes the “limit of disturbance” is the maximum disturbance level appearing with a certain probability in the electromagnetic environment of a device, equipment or system. This is the referenc
39、e value to which the other levels have to be related, in order to avoid causing interference. In some cases, this maximum disturbance level is the result of the superposition of several sources (e.g.harmonics), in other cases it is produced by a single source (e.g.non-repetitive voltage dip). It mus
40、t be emphasized that in general, the disturbance level is not a single value, but varies with position and time. In practice, the statistical distribution of the disturbance must be considered. The maximum disturbance level may be derived from actual network measurements or, possibly, theoretical st
41、udy. Because of this variability of the disturbance level, it is often very difficult or even impossible to determine the actual highest level of disturbance which may appear very infrequently. It is also generally not economical to define the compatibility level in terms of this highest value to wh
42、ich most devices would not be exposed most of the time. It therefore seems appropriate to define the compatibility level not as the “maximum value” of a disturbance but as the level of the disturbance that would be exceeded in only a small or very small number of cases the aim being for the compatib
43、ility level to cover at least95% or so of situations. The immunity level of equipment should be equal to the compatibility level or higher. The immunity level has to be checked by an appropriate test. Determining its value and the test procedure is the responsibility of a relevant Technical Committe
44、e (or is subject to agreement between the parties involved). The susceptibility level of equipment is the level of disturbance which would disturb the function of the equipment. It should be equal to, or higher than, the immunity level fixed for the tests.BS7484:1991 BSI 09-1999 3 The susceptibility
45、 level should be fixed by the manufacturer taking into account anticipated service conditions and the specified immunity limit. The susceptibility level may require consideration in statistical terms. The compatibility level is intended to serve as a reference value for trouble-free operation, in pa
46、rticular for public power supply systems to which items of equipment are connected by independent consumers not normally in contact with each other. The relation between the different levels of disturbance taking into account the statistical features is illustrated byFigure 1. In dedicated or indepe
47、ndent systems, servicing for example only one customers equipment of a particular kind, other compatibility levels may be agreed. 5 Harmonics 5.1 Description of the phenomenon Harmonics are sinusoidal voltages or currents having frequencies that are whole multiples of the frequency at which the supp
48、ly system is designed to operate (e.g.50Hz or60Hz). Harmonic disturbances are generally caused by equipment with a non-linear voltage/current characteristic. Such equipment may be regarded as current sources of harmonics. The harmonic current from the different sources produces harmonic voltage drop
49、s across the impedance of the network. This phenomenon is represented inFigure 2 in a simplified way. In reality, the different harmonic currents add vectorially. As a result of the connection of reactive loads (e.g. power factor correction capacitors) and the effect of cable capacitance, shunt and series resonance may occur in the network and cause a voltage magnification even at a point remote from the distorting load. 5.2 Sources of harmonics Harmonic currents are generated to a small extent and at low distortion levels by generation, tra
