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1、BRITISH STANDARD BS 7639:1993 Short-circuit current calculation in three-phase a.c. systems (Implementation of HD 533 S1) UDC 621.3.02.001 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7639:1993 This Briti
2、sh Standard, having been prepared under the direction of the Power Electrical Engineering Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 April 1993 BSI 04-2000 The following BSI references relate to the work on this standard: Committe
3、e reference PEL/104 Special announcement in BSI News, July 1992 ISBN 0 580 21675 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Power Electrical Engineering Standards Policy Committee (PEL/-) to Technical Committee PEL/104, upon which
4、 the following bodies were represented: British Cable Makers Confederation Electrical Installation Equipment Manufacturers Association Electricity Association Institution of Electrical Engineers GAMBICA (BEAMA Ltd.) Amendments issued since publication Amd. No.DateComments Licensed Copy: London South
5、 Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7639:1993 BSI 04-2000i Contents Page Committees responsibleInside front cover National forewordii Foreword2 Text of HD 533 S15 National annex NA (informative) Original IEC text amended b
6、y CENELEC common modificationsInside back cover National annex NB (informative) Cross-referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7639:1993 ii BSI 04-2000 National foreword Th
7、is British Standard has been prepared under the direction of the Power Electrical Engineering Standards Policy Committee PEL/-. It implements Harmonization Document HD 533 S1:1991 which was published by the European Committee for Electrotechnical Standardization (CENELEC). It was derived by CENELEC
8、from IEC 909:1988 Short circuit current calculations in three phase a.c. systems, published by the International Electrotechnical Commission (IEC). A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct
9、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 and ii, the HD title page, pages 2 to 86, an inside back cover and a back cover. This standard has been up
10、dated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI HARMONIZATION DOCUME
11、NT DOCUMENT DHARMONISATION HARMONISIERUNGDOKUMENT HD 533 S1 April 1991 UDC 621.3.02.001 Descriptors: Calculation, short-circuit current, three-phase systems English version Short-circuit current calculation in three-phase a.c. systems (IEC 909:1988, modified) Calcul des courants de court-circuit dan
12、s les rseaux triphass courant alternatif (CEI 909:1988, modifie) Berechnung von Kurzschlustrmen in Drehstromnetzen (IEC 909, modifiziert) This Harmonization Document was approved by CENELEC on 1990-03-05. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate t
13、he conditions for implementation of this Harmonization Document on a national level. Up-to-date lists and bibliographical references concerning such national implementation may be obtained on application to the Central Secretariat or to any CENELEC member. This Harmonization Document exists in three
14、 official versions (English, French, German). 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 United Kingdom. CENELEC Europe
15、an Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1991 Copyright reserved to CENELEC members Ref. No. HD 533 S1:1991 E Licensed Copy: London South
16、 Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7639:1993 BSI 04-2000 2 Foreword The CENELEC questionnaire procedure, performed for finding out whether or not the International Standard IEC 909:1988 could be accepted without textual c
17、hanges, has shown that some CENELEC common modifications were necessary for the acceptance as Harmonization Document. The reference document, together with the common modifications prepared by the CENELEC Reporting Secretariat SR 73, was submitted to the CENELEC members for formal vote. The text of
18、the draft was approved by all CENELEC members, with the exception of Austria, Finland and Norway, as HD 533 S1 on 5 March 1990. The following dates were fixed: Contents Page Foreword2 1Scope5 2Object5 3Definitions5 4Symbols, subscripts and superscripts8 4.1Symbols8 4.2Subscripts9 4.3Superscripts10 5
19、Calculation assumptions11 6Equivalent voltage source at the short-circuit location12 Section 1. Systems with short-circuit currents having no a.c. component decay (far-from-generator short circuits) 7General16 8Short-circuit parameters16 8.1Balanced short circuit16 8.2Unbalanced short circuit16 8.3S
20、hort-circuit impedances17 8.4Conversion of impedances, currents and voltages23 9Calculation of short-circuit currents23 9.1Calculation method for balanced short circuits23 9.2Calculation method for line-to-line and line-to-earth short circuits27 9.3The minimum short-circuit currents30 Section 2. Sys
21、tems with short-circuit currents having decaying a.c. components (near-to-generator short circuits) 10General30 11Short-circuit parameters31 11.1 General31 11.2 Balanced short circuit33 11.3 Unbalanced short circuit33 11.4 Equivalent voltage source at the short-circuit location33 11.5 Short-circuit
22、impedances33 11.6 Conversion of impedances, currents and voltages37 12Calculation of short-circuit currents37 12.1 General37 12.2 Calculation method for balanced short circuits37 latest date of announcement of the HD at national level(doa) 1990-09-01 latest date of publication of a new harmonized na
23、tional standard(dop) 1991-11-01 latest date of withdrawal of conflicting national standards(dow) 1991-11-01 Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7639:1993 BSI 04-20003 Page 12.3 Calculation method
24、 for line-to-line and line-to-earth short circuits46 12.4 The minimum short-circuit currents46 13Influence of motors47 13.1 Synchronous motors and synchronous compensators47 13.2 Asynchronous motors47 13.3 Static converter fed drives50 14Consideration of non-rotating loads and capacitors51 14.1 Para
25、llel capacitors51 14.2 Series capacitors51 Appendix A (informative) Calculation of short-circuit currents52 Figure 1 Short-circuit current of a far-from-generator short circuit (schematic diagram)11 Figure 2 Characterization of short circuits and their currents. The direction of current arrows is ch
26、osen arbitrarily13 Figure 3 Illustration for calculating the initial symmetrical short-circuit current in compliance with the procedure for the equivalent voltage source14 Figure 4 Short-circuit impedance of a three-phase a.c. system at the short-circuit location F15 Figure 5 Measuring of zero-seque
27、nce short-circuit impedances of electrical equipment (examples)18 Figure 6 System diagram and equivalent circuit diagram for network feeders19 Figure 7 Three-winding transformer (example)22 Figure 8 Factor x for series circuits as a function of: a) ratio R/X; b) ratio X/R24 Figure 9 System diagram i
28、llustrating a short circuit fed from several sources which are independent of one another. (In some cases the impedance between busbar B and the short-circuit location F may be neglected)25 Figure 10 Illustration of the calculation of the initial symmetrical short-circuit current in a meshed network
29、. The short-circuit current at the short-circuit location F is supplied by the feeder connection point Q through transformers T1 and T226 Page Figure 11 Chart indicating the type of short-circuit giving the highest current28 Figure 12 Short-circuit current of a near-to-generator short circuit (schem
30、atic diagram)31 Figure 13 Various short-circuit source connections32 Figure 14 Phasor diagram of a synchronous generator at rated conditions35 Figure 15 Example for the calculation of the initial symmetrical short-circuit current for a short circuit fed directly from one generator37 Figure 16 Factor
31、 for the calculation of short-circuit breaking current Ib38 Figure 17 Factors max and min for turbine generators39 Figure 18 Factors max and min for salient-pole machines40 Figure 19 Example of the calculation of the initial symmetrical short-circuit current fed from one power-station unit41 Figure
32、20 Example of the calculation of the initial symmetrical short-circuit current fed from non-meshed sources42 Figure 21 Short-circuit currents and partial short-circuit currents for three-phase short circuits between generator and transformer of a power-station unit and at the auxiliary busbar A43 Fi
33、gure 22 Explanation of the calculation of , ip, Ib and Ik for a three-phase short circuit fed from non-meshed sources according to equations (55) to (58)44 Figure 23 Example of the calculation of the initial symmetrical short-circuit current in a meshed network fed from several sources45 Figure 24 E
34、xample for the estimation of the contribution from the asynchronous motors in relation to the total short-circuit current48 Figure 25 Factor q for the calculation of the symmetrical short-circuit breaking current of asynchronous motors49 Ik 0 Ik 0 Ik 0 Ik 0 Ik 0 Ik 0 Ik 0 Licensed Copy: London South
35、 Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7639:1993 4 BSI 04-2000 Page Figure A.1 Low-voltage system with short-circuit locations F1, F2 and F3. Example 152 Figure A.2 Positive-sequence system (according to Figure A.1, page 52)
36、for the calculation of and ip at the short-circuit location F155 Figure A.3 Positive-sequence, negative-sequence and zero-sequence systems with connections at the short-circuit location F1 for the calculation at a line-to-earth short circuit58 Figure A.4 Medium voltage 33 kV/6 kV system with asynchr
37、onous motors. Example 261 Figure A.5 Medium voltage 33 kV/6 kV system with asynchronous motors (complex calculation for Example 2)66 Figure A.6 Network feeder, power-station unit (PSU) unit transformer and generator with auxiliary transformer (AT), high-voltage and low voltage asynchronous motors, E
38、xample 372 Figure A.7 Positive-sequence system for the calculation of the partial short-circuit current from high-voltage and low-voltage motors at the short-circuit location F2. Impedances are transferred to the high-voltage side of the auxiliary transformer AT with tr = 21 kV/10.5 kV = 279 Figure
39、A.8 Detail of Figure A.6, page 72. Transformers and groups of low-voltage asynchronous motors connected to the auxiliary busbar B. Transformers and low-voltage motor groups connected to the busbar C are identical80 Figure A.9 Positive-sequence system for the calculation of at the short-circuit locat
40、ion F382 Figure A.10 Positive-sequence system for the calculation of at the short-circuit location F484 Table I Voltage factor c15 Table II Calculation of short-circuit currents of asynchronous motors in the case of a short circuit at the terminals50 Page Table A.I Data of equipment for Example 1 an
41、d positive-sequence, negative-sequence and zero-sequence short-circuit impedances54 Table A.II Collection of results for Example 1 (Un = 380 V)59 Table A.III Calculation of Xk (7) for Example 2, without the influence of asynchronous motors M1 and M2 (CB1 and CB2 are open)62 Table A.IV Calculation of
42、 *Xk (per unit p.u.) for Example 2, without the influence of asynchronous motors M1 and M2 (CB1 and CB2 open)64 Table A.V Calculation of for Example 2, with asynchronous motors M1 and M2 according to Figure A.5 67 Table A.VI Data of high-voltage motors and their partial short-circuit currents at the
43、 short-circuit location on busbars B or C respectively76 Table A.VII Data of low-voltage asynchronous motors and data of transformers 10 kV 0.693 kV and 10 kV/0.4 kV respectively connected to the auxiliary busbar B. Partial short-circuit currents of the low-voltage motors at the short-circuit locati
44、on F381 Ik 0 Ik1 0 IkMAT 0 Ik 0 Ik 0 Zk T1 T2 ,() Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 11:53:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7639:1993 BSI 04-20005 1 Scope This standard is applicable to the calculation of short-circuit currents: in l
45、ow-voltage three-phase a.c. systems, in high-voltage three-phase a.c. systems with nominal voltages up to 380 kV operating at nominal frequency (50 Hz or 60 Hz). This standardized procedure is given in such a form as to facilitate as far as possible its use by non-specialist engineers. 2 Object The
46、object of this standard is to establish a general, practicable and concise procedure leading to conservative results with sufficient accuracy. For this purpose, an equivalent voltage source at the short-circuit location is considered, as described under Clause 6. This does not exclude the use of spe
47、cial methods, for example the superposition method, adjusted to particular circumstances, if they give at least the same precision. Short-circuit currents and short-circuit impedances may also be determined by system tests, by measurement on a network analyzer, or with a digital computer. In existin
48、g low-voltage systems it is possible to determine the short-circuit impedance on the basis of measurements at the location of the prospective short circuit considered. The calculation of the short-circuit impedance, based on the rated data of the electrical equipment and the topological arrangement
49、of the system has the advantage of being possible both for existing systems and for systems at the planning stage. There are two different short-circuit currents to be calculated which differ in their magnitude: the maximum short-circuit current which determines the capacity or rating of electrical equipment; the minimum short-circuit current which can be a basis, for example, for the selection of fuses and for the setting of protective devices and for
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