1、BRITISH STANDARD BS 2692-2: 1956 Incorporating Amendment Nos.1,2,3,4,5 and6 Specification for Fuses for voltages exceeding 1000Va.c. Part2: Expulsion fuses UDC 621.316.923 CONFIRMED DECEMBER 2007BS2692-2:1956 This BritishStandard, having been approved by the ElectricalIndustry StandardsCommittee and
2、endorsed by the Chairmanofthe EngineeringDivisional Council,was published under the authorityof the General Council on 30January1956 BSI 02-2000 The following BSI references relate to the work on this standard: Committee referenceELE/10/6 Draft for comment CR(ELE)7650 ISBN 0 580 02513 6 Co-operating
3、 organizations The Electrical Industry Standards Committee under whose supervision this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: The Government departments and scientific and industrial organizati
4、ons marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of the standard. Admiralty* Electric Light Fittings Association Air Ministry* Electrical Contractors Association Association of Consulting Engineers (
5、Incorporated) (Incorporated)* Electrical Contractors Association of Scotland Association of Supervising Electrical Engineering Equipment Users Association* Engineers General Post Office* British Electrical and Allied Industries Independent Cable Makers Association Research Association* Institution o
6、f Electrical Engineers British Electrical and Allied Manufacturers Ministry of Fuel and Power* Association* Ministry of Labour and National Service British Electrical Development Association (Factory Department)* British Railways, The British Transport Ministry of Supply* Commission* Ministry of Wor
7、ks Central Electricity Authority and Area National Physical Laboratory* Boards* North of Scotland Hydro-Electric Board* Cable Makers Association* Oil Companies Materials Committee* Crown Agents for Oversea Governments and Public Transport Association (Incorporated) Administrations* Radio Industry Co
8、uncil Electric Lamp Manufacturers Association War Office Association of Mining Electrical and London Transport Executive, The British Mechanical Engineers Transport Commission Engineer Surveyors Association National Coal Board High Commission of India South of Scotland Electricity Board Lloyds Regis
9、ter of Shipping Amendments issued since publication Amd. No. Date of issue Comments 2633 October1956 3625 January1960 3755 May1960 5872 July1966 611 October1970 1885 January1976 Indicated by a sideline in the marginBS2692-2:1956 BSI 02-2000 i Contents Page Co-operating organizations Inside front cov
10、er Foreword iii Section 1. General 1 Scope 1 2 Basis of specification 1 3 Definitions 2 Section 2. Rating 4 Voltage-rating 6 5 Current-rating 6 6 Breaking-capacity ratings 7 Section 3. Marking 7 Fuse-links 9 8 Current-limiting impedances 10 Section 4. Service conditions 9 Service conditions 10 Secti
11、on 5. Operation in service 10 General requirements 10 11 Liquids 11 12 Time/current characteristics 11 13 Cut-off current characteristic (for current-limiting fuses only) 11 14 Temperature-rise limits at rated current 11 Section 6. Construction 15 Components 12 16 Contacts 12 17 Fuse-links 12 18 Fus
12、e-carriers and fuse-mounts 13 19 Current-limiting impedances 13 Section 7. Type tests 20 General 13 21 Test for temperature-rise 13 22 High-voltage test: wet test for outdoor fuses 14 23 Impulse-voltage tests 15 24 Oil-penetration test for oil-tight cartridge fuse-links 16 25 Sealing test for liquid
13、 fuse-links 16 26 Weatherproof test for powder-filled cartridge-fuses for outdoor use 17 27 Tests for breaking-capacity 17 28 Criteria of failure in tests for breaking-capacity 19 Section 8. Routine tests 29 General 21 Appendix A Notes on terms in the standard relating to performance of fuses 23 App
14、endix B Selection of fuses 24 Appendix C Calculation of short-circuit fault-currents 27 Appendix D Measurement of prospective current and cut-off current 27 Appendix E Measurement of power-factor 28BS2692-2:1956 ii BSI 02-2000 Page Appendix F Measurement of recovery-voltage 29 Appendix G Example of
15、data to be included in a report of type-tests for breaking-capacity 29 Appendix H Insulation co-ordination 30 Appendix J Correction factors for atmospheric conditions during impulse-voltage tests, and for air density during wet withstand voltage tests 31 Appendix K Virtual time 31 Figure 1 Test-circ
16、uits and voltages 34 Figure 2 Test for current-limiting fuses 35 Figure 3 Determination of recovery-voltage 36 Figure 4 Prospective current oscillogram 37 Figure 5 Oscillogram for large prospective current 37 Figure 6 Examples of discrimination 38 Figure 7 Oscillogram for computation of power factor
17、 39 Figure 8 Air-density correction-factor 40 Figure 9 Correction-factor for humidity 41 Figure 10 Virtual time curves 42 Figure 11 Determination of virtual time 43 Figure 12 Dimensions for reference TA1 fuse-links. Voltage3.3kV.For use in air 44 Figure 13 Dimensions for reference TA2 fuse-links. Vo
18、ltage3.3kV.For use in air 45 Figure 14 Dimensions for Reference TA3 fuse-links. Voltage6.6/11kV.For use in air 46 Figure 15 Dimensions of Ferrule-type fuse links for use in air or oil 47 Table 1 Current-ratings for fuses other than voltage-transformer fuses 7 Table 2 Current-ratings for fuses primar
19、ily used for the protection of voltage-transformers 7 Table 3 Standard3-phase breaking-capacity ratings for fusesother than voltage-transformer fuses 8 Table 4 Standard3-phase breaking-capacity ratings forvoltage-transformer fuses 9 Table 5 Temporary test-connections for temperature-rise test 14 Tab
20、le 6 Power-frequency test-voltages for wet test on outdoor fuses 15 Table 7 Impulse-voltage tests for electrically exposed fuses 16 Table 8 Voltage settings in peakkV and r.m.s. kV of sphere-gapfor checking transient voltage of fuse operation 20 Table 9 Test-voltages in tests of longer duration than
21、 one minute 22 Table 10 25BS2692-2:1956 BSI 02-2000 iii Foreword This standard makes reference to the following BritishStandards: BS116, Oil circuit-breakers for alternating current systems. BS148, Insulating oil (low viscosity type) for transformers and switchgear. BS923, Impulse-voltage testing. B
22、S2782, Methods of testing plastics. This BritishStandard has been prepared to meet the need for a standard for fuses for a.c. circuits above1000volts, which is the upper limit of voltage for fuses covered by BS88. It is expected that additions to the standard will become necessary as knowledge incre
23、ases and, in particular, it is hoped to standardize dimensions to some extent when adequate experience has been gained with fuses in accordance with this standard. Some time must necessarily elapse before every such fuse can be supplied and certified to comply with the standard in all respects; in t
24、he meantime therefore its application should be subject to agreement between the contracting parties. 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 Standar
25、d does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1to48, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. Th
26、is will be indicated in the amendment table on the inside front cover.iv blankBS2692-2:1956 BSI 02-2000 1 Section 1. General 1 Scope This BritishStandard relates to fuses for use indoors or outdoors on alternating current systems having line-to-line voltages above1000volts at a frequency of50cycles
27、per second, and with breaking-capacities corresponding to three-phase values from25MVA to750MVA for power fuses and from50MVA to2500MVA for voltage-transformer fuses (or equivalent values for other systems). In general, these fuses are suitable for short-circuit protection only, leaving other device
28、s for protection against over-currents. The requirements of this standard apply to fuses for use in air and to fuses for use immersed in oil. This standard relates only to expulsion fuses. Where fuses depend for their correct operation as fuses on the movement of some component to provide an insulat
29、ing gap, this feature is considered as part of the fuse operation and comes within the scope of this standard. On the other hand, there are fuse-links that contain tripping devices for initiating the opening of a switch. These fuse-links are required to comply with this standard, but the satisfactor
30、y operation of the equipment operated by the tripping devices is outside the scope of the standard. The range of breaking-capacity ratings of25MVA to750MVA covers the usual applications of high-voltage fuses for power-system and voltage-transformer protection. It is recognized, however, that voltage
31、-transformer fuses may also be required for use on systems having short-circuit capacities in excess of750MVA. Where such fuses are designed to operate in series with current-limiting impedances, the values of which are more than100times the impedance of the system, their performance is practically
32、unaffected by the short-circuit current of the system, hence they may be safely used, with the appropriate impedance, on circuits having greater short-circuit capacities than750MVA. Voltage-transformer fuses without current-limiting impedances for use on systems with short-circuit currents greater t
33、han those corresponding to750MVA may be deemed to comply with this standard provided that all the requirements other than the tests set out in Clauses27 and28 are met; in such cases tests for breaking-capacity should be the subject of agreement between purchaser and manufacturer. 2 Basis of specific
34、ation a) General. This standard is based on single-phase and polyphase service conditions. Fuses complying with it are suitable for operating under a variety of conditions where the recovery-voltage across any fuse may be any voltage not exceeding its voltage-rating. Conditionsi) andii) below are ex
35、amples in which a three-phase group of fuses can break two phases of the circuit and leave the third intact, and so may impose a recovery-voltage equal to the voltage-rating of the fuse across each of the two fuses that have operated. i) The operation of fuses on a three-phase fault where the neutra
36、l of the source of supply is not connected to the fault. ii) The operation of fuses on a single-phase line-to-line fault on a three-phase system, if the load is not connected to the supply neutral, since under these conditions the fuse in the healthy line is connected to the fault via the load. In v
37、iew of the above conditions, breaking-capacity tests made on a three-phase basis should have a recovery-voltage across each phase not less than the line-to-line voltage see Sub-clause27 l) and Figure 1(a). The use of a three-phase3-wire test circuit with one fuse of a three-phase group of fuses repl
38、aced by a link of negligible impedance enables this condition to be achieved. The same circuit may be used to test fuses intended for single-phase duty, two at a time. The test circuit severity on one of the fuses shall comply with the circuit conditions prescribed in Sub-clause27 g) and for current
39、-limiting fuses also with Figure 2. Single-phase tests of one fuse of a three-phase group of fuses, or of fuses for single-phase systems shall also comply with the requirements of Sub-clause27 g). Fuses complying with this standard are suitable for service on single-phase or two-phase systems where
40、the line-to-line voltage is the same as that of a three-phase system for which they have been tested (see Clause10).BS2692-2:1956 2 BSI 02-2000 b) Breaking-capacity rating. For the purpose of this standard the breaking-capacity rating of a fuse is expressed as a prospective current at its voltage-ra
41、ting. When recording the results obtained during breaking-capacity type-tests the prospective current and the recovery-voltage shall be stated. When a fuse exhibits current-limiting characteristics the current broken will be less than the peak current associated with the prospective current. In this
42、 case, when assessing the performance of the fuse, it will be deemed to have broken the prospective current. c) MVA rating. For the practical convenience of specifying MVA breaking-capacity ratings for fuses and for comparing a given rating with the MVA value for a short-circuit at a given point in
43、a supply network, the breaking-capacity rating in kilo-amperes assigned to a fuse is converted into an MVA rating by multiplying the former by its voltage-rating in kilovolts and by the phase-factor. Thus the value of single-phase MVA is the product of single-phase r.m.s. kilo-amperes and the voltag
44、e-rating in kilovolts, and the value of three-phase MVA is obtained by multiplying the single-phase r.m.s. kilo-amperes by the voltage-rating in kilovolts and by(not by3). d) Severity of duty. The specification standardizes criteria of severity of duty under which type-tests are made and ratings are
45、 assigned. It is recognized that the severity of duty imposed on a fuse may also depend on the form of restriking-voltage, but, since present knowledge is insufficient to enable restriking-voltage characteristics to be standardized, only those factors which control the amplitude of the restriking-vo
46、ltage have been included. It is generally agreed that the restriking-voltage characteristics obtainable in testing stations are more onerous than those obtained under normal service conditions. The permissible peak value of the transient voltage which may be produced by the fuse is specified see Sub
47、-clause28 a)ix). 3 Definitions For the purposes of this BritishStandard the following definitions shall apply: 3.1 fuse a device for protecting a circuit against damage from an excessive current flowing in it, by opening the circuit on the melting of a fuse-element by such excessive current. The fus
48、e consists of all the parts that form the complete device, including any current-limiting impedance association therewith 3.2 fuse-element the part of a fuse which is designed to melt and thus open a circuit in some designs the fuse-element includes other attachments which are renewed when the fuse
49、is re-wired 3.3 cartridge a “totally-enclosing” fuse-element container, consisting of insulating material; generally tubular, with its ends enclosed by caps of metal or other material. The term “totally-enclosing” is deemed not to exclude the use of devices in connection with indicating or pressure-release 3.4 cartridge-fuse a fuse in which the fuse-element is enclosed in a cartridge 3.5 oil-tight cartridge-fuse a cartridge-fuse which excludes oil from the interior of the cartridge when totally immersed in oil, and in
