1、BRITISH STANDARD BS EN 60868:1993 Flickermeter Functional and design specifications The European Standard EN 60868:1993 has the status of a British Standard UDC 621.317.7BS EN 60868:1993 This British Standard, having been prepared under the directionof the General Electrotechnical Standards PolicyCo
2、mmittee, was publishedunder the authority ofthe Standards Board and comesinto effect on 15 August 1993 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference GEL/110 Drafts for comment 84/22884 DC, 88/24779 DC ISBN 0 580 22455 4 Cooperating organizations Th
3、e European Committee for Electrotechnical Standardization (CENELEC), under whose supervision this European Standard was prepared, comprises the national committees of the following countries: Austria Italy Belgium Luxembourg Denmark Netherlands Finland Norway France Portugal Germany Spain Greece Swe
4、den Iceland Switzerland Ireland United Kingdom Amendments issued since publication Amd. No. Date CommentsBS EN 60868:1993 BSI 08-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN 60868 3 National annex NA (informative) Appendix D to IEC 255-
5、8:1978 17 National annex NB (informative) Committees responsible 22 National annex NC (informative) Cross-references Inside back coverBS EN 60868:1993 ii BSI 08-1999 National foreword This British Standard has been prepared under the direction of the General Electrotechnical Standards Policy Committ
6、ee and is the English language version of EN60868:1993, Flickermeter Functional and design specifications, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC868:1986 + A1:1990 published by the International Electrotechnical Commission (IEC).
7、This British Standard supersedes BS6796:1986 which is withdrawn. BS EN 60868-0:1993 is complementary to this standard as it covers statistical evaluation of flicker severity. NOTEThe reference in note3 to Table IV should refer to Appendix D of IEC255-8:1978. This appendix was deleted in the1990 revi
8、sion of IEC255-8 and it has therefore been reproduced in National annex NA. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confe
9、r immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theENtitle page, pages2 to22, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This wi
10、ll be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 60868 April 1993 UDC 621.317.7 Supersedes HD 498 S2:1992 Descriptors: Measuring instrument, flickermeter, design, performance, specification, test English version Flickermeter Functi
11、onal and design specifications (IEC 868:1986 + A1:1990) Flickermtre Spcifications fonctionnelles et de conception (CEI 868:1986 + A1:1990) Flickermeter Funktionsbeschreibung und Auslegungsspezifikation (IEC 868:1986 + A1:1990) This European Standard was approved by CENELEC on1993-03-09. CENELEC memb
12、ers are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on applicati
13、on to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat h
14、as the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CENELEC European
15、 Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1993 Copyright reserved to CENELEC members Ref. No. EN 60868:1993 EEN 60868:1993 2 BSI 08-1999 For
16、eword At the request of72 Technical Board, HD498S2:1992 (IEC868:1986 + A1:1990) was submitted to the CENELEC voting procedure for conversion into a European Standard. The text of the International Standard was approved by CENELEC as EN60868 on9March1993. The following dates were fixed: Annexes desig
17、nated “normative” are part of the body of the standard. In this standard, Annex ZA is normative. Contents Page Foreword 2 Introduction 3 1 Scope and object 3 2 Description of the instrument 3 3 Specification 5 4 Type test specifications 8 Appendix A Evaluation of flicker severity on thebasis of the
18、output of the IEC flickermeter 14 Annex ZA (normative) Other international publications quoted in this standard with thereferences of the relevant European publications 16 Figure 1 Functional diagram of UIE flickermeter 12 Figure 2 Basic illustration of the time-at-level method 13 Table I Normalized
19、 flickermeter response for sinusoidal voltage fluctuations 5 Table II Normalized flickermeter response forrectangular voltage fluctuations 6 Table III 6 Table IV 11 Table A.I Test specifications for flickermeter classifier 15 latest date of publication of an identical national standard (dop) 1994-03
20、-01 latest date of withdrawal of conflicting national standards (dow) EN60868:1993 BSI 08-1999 3 INTRODUCTION This report gives a functional and design specification for flicker measuring apparatus intended to indicate the correct flicker perception level for all practical voltage fluctuation wavefo
21、rms. Sufficient information is presented to enable such an instrument to be constructed. The method of flicker severity assessment from flickermeter output data will form the subject of other publications. In its present form, this report is not intended to be an appendix to IEC Publications555-3: D
22、isturbances in Supply Systems Caused by Household Appliances and Similar Electrical Equipment, Part3: Voltage Fluctuations. This report is based on specifications prepared by the Disturbances Study Committee of the International Union for Electroheat (UIE). 1 Scope and object The purpose of this rep
23、ort is to provide basic information for the design and the implementation of an analogue or digital flicker measuring apparatus. It does not specify the method of calculating a flicker severity value, or give tolerable limit values. 2 Description of the instrument The description given below is base
24、d on an analogue implementation. A partly or completely digital meter is equally acceptable provided that it offers the same functional characteristics. The flickermeter architecture is described by the block diagram of Figure 1, page12, and can be divided into two parts, each performing one of the
25、following tasks: simulation of the response of the lamp-eye-brain chain; on-line statistical analysis of the flicker signal and presentation of the results. The first task is performed by blocks2, 3 and 4 of Figure 1, whilst the second task is accomplished by block5. Although this last block is not
26、mandatory, as flicker signal analysis can be performed off-line using a suitable recording medium, its inclusion is recommended because it will allow a more complete and efficient use of the instrument. 2.1 Block 1 Input voltage adaptor and calibration checking circuit This block contains a signal g
27、enerator to check the calibration of the flickermeter on site and a voltage adapting circuit that scales the mean r.m.s. value of the input mains frequency voltage down to an internal reference level. In this way flicker measurements can be made independently from the actual input carrier voltage le
28、vel and expressed as a percent ratio. Taps on the input transformer establish suitable input voltage ranges to keep the input signal to the voltage adaptor within its permissible range. 2.2 Block 2 Square law demodulator The purpose of this block is to recover the voltage fluctuation by squaring the
29、 input voltage scaled to the reference level, thus simulating the behaviour of the lamp. 2.3 Blocks 3 and 4 Weighting filters, squaring and smoothing Block3 is composed of a cascade of two filters and a measuring range selector, which can precede or follow the selective filter circuit. The first fil
30、ter eliminates the d.c. and double mains frequency ripple components of the demodulator output. The second does the shaping of the flickermeter frequency response to the modulating fluctuation, as follows: the weighting filter block simulates the frequency response to sinusoidal voltage fluctuations
31、 of a coiled coil filament gas filled lamp (60 W 230 V) combined with the human visual system. The response function is based on the perceptibility threshold found for each frequency on50% of the persons tested 1) . 1) A reference filament lamp for100130 V systems would have a different frequency re
32、sponse and would require a corresponding adjustment of the weighting filter. The characteristics of discharge lamps are totally different, and wider modifications of this report would be necessary to take them into account.EN 60868:1993 4 BSI 08-1999 Block4 is composed of a squaring multiplier and a
33、 first order low-pass filter. The human flicker sensation via lamp, eye and brain is simulated by the combined non-linear response of blocks2, 3 and4. Block3 alone is based on the borderline perceptibility curve for sinusoidal voltage fluctuations; the correct weighting of non-sinusoidal and stochas
34、tic fluctuations is achieved by an appropriate choice of the complex transfer function for blocks3 and4. Accordingly the correct performance of the model has also been checked with periodic rectangular signals as well as with transient signals. The output of block4 represents the instantaneous flick
35、er sensation. 2.4 Block 5 On-line statistical analysis Block5 incorporates a microprocessor that performs an on-line analysis of the flicker level, thus allowing direct calculation of significant evaluation parameters. A suitable interface allows data presentation and recording. The use of this bloc
36、k is related to methods of deriving measures of flicker severity by statistical analysis. The statistical analysis, whether performed on-line by block5 or off-line on a recording of the output of block4, shall be made by subdividing the amplitude of the flicker level signal into a suitable number of
37、 classes. The flicker level signal is sampled at a constant rate. Every time that the appropriate value occurs, the counter of the corresponding class is incremented by one. In this way, the frequency distribution function of the input values is obtained. By choosing a scanning frequency sufficientl
38、y higher than the maximum flicker frequency, the final result at the end of the measuring interval represents the distribution of flicker level duration in each class. Adding the content of the counters of all classes and expressing the count of each class relative to the total gives the probability
39、 density function of the flicker levels. From this, one obtains the cumulative probability function used in the time-at-level statistical method. Figure 2, page13, schematically represents the statistical analysis method, limited for simplicity of presentation to10 classes. From the cumulative proba
40、bility function, significant statistical values can be obtained such as mean, standard deviation, flicker level being exceeded for a given percentage of time or, alternatively, the percentage of time an assigned flicker level has been exceeded. The observation period is defined by two adjustable tim
41、e intervals: T shortand T long . The long interval defines the total observation time and is always a multiple of the short interval: (T long= n T short ). For on-line processing, immediately after conclusion of each short time interval, the statistical analysis of the next interval is started and t
42、he results for the expired interval are made available for output. In this way, n short time analyses will be available for a given observation period T long , together with the results for the total interval. Cumulative probability function plots should preferably be made by using a Gaussian normal
43、 distribution scale. 2.5 Outputs The flickermeter diagram in Figure 1, page12, shows a number of outputs between blocks1 and5. The outputs marked with an asterisk are not essential, but may allow a full exploitation of the instrument potential for the investigation of voltage fluctuations. Further o
44、ptional outputs may be considered. 2.5.1 The aim of optional output1 and associated r.m.s. meter is to display the voltage fluctuation waveform in terms of changes in r.m.s. value of the input voltage. This can be achieved by squaring, integrating between zero crossings on each half-cycle and square
45、 rooting the signal. In order to observe small voltage changes with good resolution, an adjustable d.c. offset and rectification should be provided. 2.5.2 Output2 is mainly intended for checking the response of block3 and making adjustments. 2.5.3 Output3 gives an instantaneous linear indication of
46、the relative voltage changeexpressed as per cent equivalent of an8.8Hz sinusoidal wave modulation. This output is useful to select the proper measuring range. 2.5.4 Output4 gives the1 min integral of the instantaneous flicker sensation. %V V -EN60868:1993 BSI 08-1999 5 2.5.5 Output5 represents the i
47、nstantaneous flicker sensation and can be recorded on a strip-chart recorder for a quick on-site evaluation, or on magnetic tape for long duration measurements and for later processing. 2.5.6 Output6 in block5 is connected to a serial digital interface suitable for a printer and a magnetic tape reco
48、rder. Using another digital to analogue converting interface, analogue plots of the cumulative probability function can be obtained directly from this block. 3 Specification 3.1 Analogue response The overall analogue response from the instrument input to the output of block4 is given in Table I and
49、Table II for sinusoidal and rectangular voltage fluctuations as defined in IEC Publication555-3. One unit output from block4 corresponds to the reference human flicker perceptibility threshold. The response is centred at8.8Hz for sinusoidal modulation. The prescribed accuracy is achieved if the input values for sine and square-wave modulations are within 5% of the tabulated values, for an output of one unit of perceptibility. Table I Normalized flickermeter response for sinusoidal voltage fluctuations Input relative vol
