EN 60156-1995 en Insulating Liquids Determination of the Breakdown Voltage at Power Frequency Test Method《绝缘液 工业频率下击穿电压的测定 试验方法(IEC 156-1995)》.pdf

《EN 60156-1995 en Insulating Liquids Determination of the Breakdown Voltage at Power Frequency Test Method《绝缘液 工业频率下击穿电压的测定 试验方法(IEC 156-1995)》.pdf》由会员分享，可在线阅读，更多相关《EN 60156-1995 en Insulating Liquids Determination of the Breakdown Voltage at Power Frequency Test Method《绝缘液 工业频率下击穿电压的测定 试验方法(IEC 156-1995)》.pdf（18页珍藏版）》请在麦多课文档分享上搜索。

1、- CENELEC *EN*bOL5b 95 = 3404583 OL7l105b 872 BRITISH STANDARD Insulating liquids - Determination of the breakdown voltage at power frequency - Test method The European Standard EN 60156 : 1995 has the status of a British Standard ICs 29.040.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED B

2、Y COPYRIGHT LAW 3s EN i0156 : 1996 EC 156 : 1995 BS EN 60166 : 1996 CENELEC +ENtbOL5b 95 34045133 OL7L057 709 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technicd Committee GW10, Flui the instrument then used shall be calibrated against

3、a standard up to the full voltage which it is desired to measure. A method of calibration which has been found satisfactory is the use of a transfer standard. This is an auxiliary measuring device which is connected in place of the test cell between the high-voltage terminals to which it presents th

4、e same impedance as the filled test cell. The auxiliary device is separately calibrated against a primary standard, for example, a sphere gap in accordance with IEC 52 (see also IEC 60). 4 Test assembly 4.1 Test cell The volume of the cell shall be between 350 ml and 600 ml. The cell shall be made o

5、f material that is electrically insulating, transparent and chemically inert, resistant to the insulating liquid and the cleaning agents which may be used. The cell shall be provided with a cover and shall be designed to permit easy removal of the electrodes for cleaning and maintenance. Examples of

6、 suitable cell designs are given in figures 1 and 2. 4.2 Electrodes The electrodes shall be made either of brass, bronze or austenitic stainless steel. They shall be polished and, in shape, either spherical (123 mm to 13,O mm diameter) as shown in figure 1 or partially spherical of the shape and dim

7、ensions given in figure 2. The axis of the electrode system shall be horizontal, and at least 40 mm below the surface of the test liquid in the cell. No part of the electrode shall be closer than 12 mm to the cell wall or stirrer. The gap between the electrodes shall be 250 mm * 0,05 mm. CENELEC *EN

8、*h015b 75 W 3404583 OL7LObb 711 = Page 7 EN 60156 : 1995 The electrodes shall be examined frequently for pitting or other damage, and shall be maintained or replaced as soon as such damage is observed. 4.3 Stirring (optional) The test may be conducted with or without stirring. Differences between te

9、sts with or without stirring have not been found statistically significant. A stirrer, however, may be convenient especially with apparatus capable of automatic operation. Stirring may be achieved by means of a two-bladed impeller of effective diameter 20 mm to 25 mm, axial depth 5 mm to 10 mm, rota

10、ting at a speed of 250 r.p.m to 300 r.p.m. The impeller shall not entrain air bubbles and preferably rotate in such a direction that the resulting liquid flow is directed downward. It shall be constructed so that it is easily cleaned. Stirring by means of a magnetic bar (20 mm to 25 mm in length and

11、 5 mm to 10 mm in diameter) is an acceptable alternative when there is no risk of removing magnetic particles. The dimensions of the stirring device shall conform to the ctearance requirements in 4.2. 5 Preparation of electrodes New electrodes, pitted electrodes, electrodes which have not been prope

12、rly stored for a considerable time shall be cleaned by the following procedure: - clean all surfaces with a suitable volatile solvent and allow the solvent to evaporate; - polish with fine abrasive powder (for example, jewellers rouge) or abrasive paper or cloth (for example, crocus cloth); - after

13、polishing, clean with petroleum spirit (reagent quality: boiling range 60 OC - 80 OC) followed by acetone (reagent quality); - assemble the electrodes in the cell, fill with a clean, unused insulating liquid of the type to be tested next, and raise the electrode voltage to breakdown 24 times. 6 Test

14、 assembly preparation It is recommended that a separate test cell assembly be reserved for each insulating liquid tY Pe- Test assemblies shall be stored in a dry place, covered and filled with dry insulating liquid of the type in regular use in the cell. On change of the type of liquid under test, r

15、emove all residues of the previous liquid with an appropriate solvent, rinse the assembly with clean, dry liquid of the same type as that to be tested, drain and refill. CENELEC *EN*bO156 95 = 3404583 0173067 658 Page 8 EN 60156 : 1995 7 Sampling 7.1 Sample containers Sample size should be approxima

16、tely three times the capacity of the test cell. Appropriate sample containers shall comply with IEC 475. An amber glass bottle is the preferred container. Clear glass bottles may be used but they shall be shielded from direct light until ready to be tested. Plastic containers which are not attacked

17、by the liquid to be tested may be used, but these shall not be used more than once. For sealing, screw caps with polyolefine or polytetrafluoroethylene insert are preferred. . Containers and caps shall be cleaned by washing with a suitable solvent to remove residues of an earlier sample. Containers

18、shall next be rinsed with acetone, traces of which shall be removed by blowing with warm air. After cleaning, containers shall be immediately capped and kept sealed until used. 7.2 Sampling technique Sampling of new and used insulating liquids shall be carried out in full compliance with procedures

19、detailed in IEC 475. When sampling, containers should be almost filled with sample, leaving about 3 70 of the container volume as free air space. Breakdown voltage is extremely sensitive to the slightest contamination of the sample by water and particulate matters. Special reference is made to preca

20、utions necessary to avoid contamination of the sample and the need for trained personnel and experienced supervision. Unless otherwise required, the sample is taken where the liquid is likely to be most contaminated, usually at the lowest point of the container holding it. 8 Condition of the sample

21、The test is carried out, unless otherwise specified, on the sample as received without drying or degassing. At the time of test, the temperatures of the test liquid and ambient air shall not differ by more than 5 OC and for referee tests the liquid temperature shall be 20 OC f 5 OC. 9 Test procedure

22、 9.1 Sample preparation Immediately before filling the test cell, the sample container is gently agitated and turned over several times in such a way as to ensure as far as possible a homogeneous distribution of the impurities contained in the liquid without causing the formation of air bubbles. Unn

23、ecessary exposure to the ambient air of the sample shall be avoided. Page 9 EN 60156 : 1995 CENELEC *EN*b015b 95 3YOY583 0171Ob8 594 H 9.2 Filling of the cell Immediately before commencing the test, drain the test cell and rinse the walls, electrodes and other component parts, with the test sample.

24、Drain and slowly fill with the test sample avoiding the formation of air bubbles. Measure and record the temperature of the liquid. Position the cell in the test equipment and start the stirrer if used. 9.3 Application of voltage The first application of voltage is started approximately 5 min after

25、completion of filling and checking that no air bubbles are visible in the electrode gap. Apply voltage to the electrodes and uniformly increase voltage from zero at the rate of 2,O kV s-l * 0,2 kV s-l until breakdown occurs. The breakdown voltage is the maximum voltage reached at the time the circui

26、t is opened either automatically (established arc) or manually (visible or audible discharge detected). Record the value. Carry out six breakdowns on the same cell filling allowing a pause of at least 2 min after each breakdown before re-application of voltage. Check that no gas bubbles are present

27、within the electrode gap. If a stirrer is used, it shall run continuously throughout the test. Calculate the mean value of the six breakdowns in kilovolts. 10 Report Report the mean value, in kilovolts, of the six breakdowns as the test result. The report shall also include: the sample identificatio

28、n, the value of each individual breakdown, the type of electrodes used, the frequency of the test voltage, the temperature of the liquid, the use of a stirrer (if any). 11 Test data dispersion The scatter of individual breakdown voltages has been found to be very dependent on the value of the result

29、. The graphical representation of figure 3 indicates the values of standard deviation/mean ratio which have been found in a large body of test data in several laboratories using transformer oil. The full line in the graph shows the distribution of the median value of SD/mean as a function of the val

30、ue of the mean. The dotted lines indicate the expected 95 % range of values of SD/mean as a function of the value of the mean. CENELEC *EN*bOLSb 95 = 3404583 OL7LOb 420 Page 10 EN 60156 : 1995 110 - Rsine poxyde Epoxy resin 100 II I . -112- Figure 1 - Exemple dune cellule et dlectrodes sphriques app

31、ropries Example of suitable cell and spherical electrodes Mthacrylate de mthyle Methyl methacrylate Figure 2 - Exemple dune cellule et dlectrodes hmisphriques appropries Example of suitable cell and partially spherical electrodes Page 11 EN 60156 : 1995 Figure 3 - Reprsentation graphique du coeffici

32、ent de variation (rapport de lcart type a ia valeur moyenne) en fonction de la moyenne de tension de claquage Graphical representation of coefficient of variation (standard deviation/ mean ratio) versus mean breakdown voltage CENELEC *EN*b02Sb 95 3404583 0171071 089 Page 12 EN 60156 : 1995 Annex ZA

33、(normative) Normative references to international publications with their corresponding European publications Thjs European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publ

34、ications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including a

35、mendments). NOTE. When an international publication has been modified by CENELEC Common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title E“D Year IEC 52 1960 Recommendations for voltage memurernent by - - IEC 60 series High-voltage test techniques m 588.1 s1 1991

36、 IEC 475 1974 Method of sampling liquid dielectrics - mans of sphere-gaps (one sphere earthed) EN 60060-2 1994 - O BSI 1996 CENELEC +ENxbOLSb 95 rn 3404583 0373072 T35 rn BS EN 60156 : 1995 List of references See national foreword. CENELEC tENtb015b 95 m 3YOY583 0171073 951 m BS EN 60156 : 1996 IEC

37、156 : 1995 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Contract requi

38、rements 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. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess

39、 the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the responsible technical committee, the identity o

40、f which can be found on the inside front cover. Tel O181 996 9ooo; Fax: 0181 996 7400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign s

41、tandards publications should be addressed to Customer Services, Sales Department at Chiswick Tel O181 996 7000, Fax: O181 996 7001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless othe

42、rwise requested. Information on standards BSI provides a wide range of information on national, European and intemational standards through its Library, the Standardline Database, the BSI Information Technology Service (BITS) and its Technical Help to Exporters Service. Contact the Information Depar

43、tment at Chiswick: Tel O181 996 7111; Fax: O181 996 7048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Customer Services, Membership at Chiswick Tel: 01

44、81 996 7002; Fax: O181 996 7001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored

45、in a retrieval system or transmitted in any form or by any means - electronic, photocopying, recording or otherwise - without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or gr

46、ade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Detajls and advice can be obtained fiom the Copyright Manager, BSI, 389 Chiswick High Road, London W4 4AL. ISBN O 680 26270 1 GELIO