1、BRITISH STANDARD BSEN 61620:1999 IEC61620: 1998 Insulating liquids Determination of the dielectric dissipation factor by measurement of the conductance and capacitance Test method The European Standard EN61620:1999 has the status of a BritishStandard ICS29.040.01BSEN61620:1999 This BritishStandard,
2、havingbeen prepared under thedirectionof the ElectrotechnicalSector Committee, was published underthe authority of the Standards Committee and comesinto effect on 15April1999 BSI03-2000 ISBN 0 580 32221 1 National foreword This BritishStandard is the English language version of EN61620:1999. It is i
3、dentical with IEC61620:1998. The UK participation in its preparation was entrusted to Technical Committee GEL/10, Fluids for electrotechnical applications, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries
4、 on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. From1January1997, all IEC pub
5、lications have the number60000 added to the old number. For instance, IEC27-1 has been renumbered as IEC60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identifiers from both systems. Cross-references Attention is drawn to the fact
6、 that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with their corresponding European publications. The BritishStandards which implement these international or European publications may be found in the BSI Standards Catalogue under
7、 the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct app
8、lication. 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, pagesi andii, theEN title page, pages2 to14 and a back cover. This standard has been updated (see copyright date) and
9、 may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSEN61620:1999 BSI 03-2000 i Contents Page National foreword Inside front cover Foreword 2 Text of EN61620 3ii blankEUROPEAN STAND
10、ARD NORME EUROPENNE EUROPISCHE NORM EN61620 January1999 ICS17.220.99; 29.040.01 Descriptors: Electrical insulating materials, liquid electrical insulating materials, tests, electric measurements, dissipation factor, capacitance, procedure, test equipment, labelling English version Insulating liquids
11、 Determination of the dielectric dissipation factor by measurement of the conductance and capacitance Test method (IEC61620:1998) Isolants liquides Dtermination du facteur de dissipation dilectrique par la mesure de la conductanceetde la capacit Mthode dessai (CEI61620:1998) Isolierflssigkeiten Best
12、immungdesPermittivitts- Verlustfaktorsdurch Messung der Konduktanz(Leitfhigkeit) und Kapazitt Prfverfahren (IEC61620:1998) This European Standard was approved by CENELEC on1999-01-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giv
13、ing 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 application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official
14、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 has the same status as the official versions. CENELEC members are the national electrotechnical committee
15、s of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrote
16、chnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1999 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN61620:1999EEN61620:1999 BSI 03-2000 2 Foreword The text of documen
17、t10/446+446A/FDIS, future edition1 of IEC61620, prepared by IEC TC10, Fluids for electrotechnical applications, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN61620 on1999-01-01. The following dates were fixed: Annexes designated “normative” are part of the body of t
18、he standard. Annexes designated “informative” are given for information only. In this standard, Annex A, Annex B and Annex ZA are normative and Annex C and Annex D are informative. Annex ZA has been added by CENELEC. Endorsement notice The text of the International Standard IEC61620:1998 was approve
19、d by CENELEC as a European Standard without any modification. In the official version, for Annex D, Bibliography, the following notes have to be added for the standards indicated: Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Normative references 3 3 Definitions 3 4 Principle of operation 4 5
20、Apparatus 5 6 Sampling 7 7 Labelling 7 8 Procedure 7 9 Expression of results 8 10 Test report 9 11 Precision 9 Annex A (normative) Exhaustive cleaningprocedure for the test cells 10 Annex B (normative) Simplified cleaningprocedurefor test cells devotedtoonlyonetypeofliquid 10 Annex C (informative) G
21、eneral considerationsonthe factors influencingtheconduction of liquids 10 Annex D (informative) Bibliography 13 Annex ZA (normative) Normative references tointernationalpublications with their correspondingEuropean publications 14 Figure 1 Principle of operation usingthesquarewave method 4 Figure 2
22、Block diagram for the measuringapparatus 5 Figure 3 Example of a test cell designedforhighlyinsulating liquids 6 Figure 4 Vectorial representation ofvoltageandcurrents with angles and 11 Table 1 Values of r and R according tothecondition of the mineral insulating oil 9 latest date by which the ENhas
23、 to be implemented at national level by publication of an identical national standard or by endorsement (dop)1999-10-01 latest date by which the national standards conflicting with the EN haveto be withdrawn (dow)2001-10-01 IEC60836 NOTEHarmonized as HD565 S1:1993 (not modified). IEC60867 NOTEHarmon
24、ized as EN60867:1994 (notmodified). IEC60963 NOTEHarmonized as HD582 S1:1991 (not modified). IEC61099 NOTEHarmonized as EN61099:1992 (notmodified).EN61620:1999 BSI 03-2000 3 Introduction The conductivity B is a characteristic of a liquid only if it is measured at thermodynamic equilibrium. To fulfil
25、 this requirement high electric stress and/or prolonged voltage application is to be avoided, this is not the case in IEC60247 for the d.c. resistivity measurement (electric stress up to250Vmm 1 , conventional arbitrary time of electrification1min). There is a simple relationship between the dielect
26、ric dissipation factor tan , the conductivity B and the permittivity of the liquid with no (or negligible) dipolar losses, which is the case of most liquids for electrotechnical applications: where =2 ;f and f is the frequency of the voltage. Therefore, the measurement of either tan or B gives the s
27、ame information on the conduction properties of the liquid. In fact, very often in practice, there are large discrepancies between the resistivity calculated from the measurement of tan with conventional apparatus and the d.c. resistivity measured following the recommendation of IEC60247. New device
28、s for the measurement of the conductivity B at thermodynamic equilibrium are currently available. They are able to measure easily and with precision very low values of B. The capabilities of this new equipment allow measurements of B of unused insulating liquids even at room temperature. 1 Scope Thi
29、s International Standard describes a method for the simultaneous measurement of conductance G and capacitance C enabling the calculation of the dielectric dissipation factor tan of insulating liquids. The proposed method applies both to unused insulating liquids and insulating liquids in service in
30、transformers and in other electrical equipment. The standard is no substitute for IEC60247; rather it complements it insofar as it is particularly suited to highly insulating liquids and it recommends a method of measurement for these liquids. This method allows values of the dielectric dissipation
31、factor as low as10 6at power frequency to be determined with certainty. Moreover, the range of measurements of tan lies between10 6and1 and can be extended up to200 in particular conditions. 2 Normative references The following normative documents contain provisions which, through reference in this
32、text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the mos
33、t recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC60247:1978, Measurement of relative permittivity, dielectric dissipation factor and d.c. resistivity of insulating liquids. IEC60475:1974, Method of
34、sampling liquid dielectrics. ISO5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part1:General principles and definitions. ISO5725-2:1994, Accuracy (trueness and precision) of measurement methods and results Part2:Basic method for the determination of repeatability a
35、nd reproducibility of a standard measurement method. ISO5725-3:1994, Accuracy (trueness and precision) of measurement methods and results Part3:Intermediate measures of the precision of a standard measurement method. ISO5725-4:1994, Accuracy (trueness and precision) of measurement methods and result
36、s Part4:Basic methods for the determination of the trueness of a standard measurement method. 3 Definitions For the purpose of this International Standard, the following definitions apply 3.1 conductivity (B) quantity related to the electric field strength E and to the conduction current density j b
37、y j =BE 3.2 resistivity ( ) reciprocal of the conductivity B, given byEN61620:1999 4 BSI 03-2000 3.3 resistance (R) the resistance of the liquid-filled test cell is the ratio of the voltage V applied to the cell to the direct or in-phase current I R , and is given by in the simplest case of plane pa
38、rallel electrodes of area A and with a gap distance L, 3.4 conductance (G) reciprocal of the resistance, given by 3.5 capacitance (C) the capacitance of the liquid-filled test cell is the ratio of the charge Q of the electrodes to the voltageV applied to the test cell. For a plane capacitor, where i
39、s the permittivity of the liquid. 3.6 dielectric dissipation factor (dielectric loss tangent tan ) for a material subjected to a sinusoidal voltage, tan is the ratio of the value of the absorbed active power to the value of the reactive power. In the simple case of a capacitance C shunted by a resis
40、tance R, where =2;f and f is the frequency of the voltage. details about the factors influencing the conduction of liquids can be found in Annex C 4 Principle of operation The principle of operation is to measure both the capacitive current and the conduction current by applying an alternate square
41、wave voltage to the test cell. The capacitive current is measured during the rise time and the conduction current is measured during the stable period of the voltage, but prior to any possible disturbance of the electric field due to ion accumulation. The currents can be measured at both positive an
42、d negative half-waves of the alternate square wave voltage for a number of cycles to increase the accuracy of the measurement (see Figure 1 and6 to12 1) ). The square wave voltage V(t) of amplitude V, is periodically reversed with a slope d V/dt. The currentI during the rise and fall of the voltage
43、is the sum of the capacitive current (displacement current) and the conduction current, i.e. The capacitive current I Cis measured during the rising and falling periods of V(t). R V I R - = G 1 R - = 1) Figures in square brackets refer to the bibliography in Annex D. Figure 1 Principle of operation
44、using the square wave method IC dV dt - V R - + =EN61620:1999 BSI 03-2000 5 The conduction current I Ris measured at the flat parts of V(t), since V/RI C , after the system has settled for a time at the beginning of each flat period. The capacitance C, the resistance R (orconductance G) and tan at a
45、 given angular frequency can be determined from the following relations: 5 Apparatus Apparatus specifically constructed or assembled from stand-alone instruments can be used to realize this measurement method. The block diagram shown in Figure 2, and the following subclauses illustrate an appropriat
46、e equipment. 5.1 Test cell Three terminal test cells designed according to the recommendations given in IEC60247 are generally suitable for this measurement. An additional type of cell in which there is no bridge made by any solid insulating material between the measurement electrodes, as shown in F
47、igure 3, can be used. This type of cell often proves more accurate on highly insulating liquids. C I c dV dt - - = R V I R - = or G I R V - = Figure 2 Block diagram for the measuring apparatusEN61620:1999 6 BSI 03-2000 The distance between the outer and the inner electrode is typically4mm; the minim
48、um distance should not be lower than1mm. The material recommended for the electrodes is stainless steel. As an example, the diameter of the inner electrode is43mm, that of the outer electrode is51mm; the height of the electrodes is60mm; the diameter of the stainless steel vessel is65mm. This type of
49、 test cell was designed to minimise the effects of contamination from the surfaces in contact with the liquid: although the surface in contact is large, the ratio =“electrode surfaces”/“liquid volume” is rather small ( =2,6cm 1 ) due to the large volume of liquid (v =200cm 3 ). NOTEIt is recommended to restrict the use of a given cell to a particular type of liquid. 5.2 Heating device The heating device shall be adequate to maintain t
