1、 IEC 60909-3 Edition 3.0 2009-03 INTERNATIONAL STANDARD NORME INTERNATIONALE Short-circuit currents in three-phase AC systems Part 3: Currents during two separate simultaneous line-to-earth short circuits and partial short-circuit currents flowing through earth Courants de court-circuit dans les rse
2、aux triphass courant alternatif Partie 3: Courants durant deux courts-circuits monophass simultans spars la terre et courants de court-circuit partiels scoulant travers la terre IEC 60909-3:2009 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2009 IEC, Geneva, Switzerland All rights reserved. Unle
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17、.0 2009-03 INTERNATIONAL STANDARD NORME INTERNATIONALE Short-circuit currents in three-phase AC systems Part 3: Currents during two separate simultaneous line-to-earth short circuits and partial short-circuit currents flowing through earth Courants de court-circuit dans les rseaux triphass courant a
18、lternatif Partie 3: Courants durant deux courts-circuits monophass simultans spars la terre et courants de court-circuit partiels scoulant travers la terre INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE XA ICS 17.220.01; 29.240.20 PRICE CODE CODE PRIX ISBN 2-831
19、8-1027-8 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale 2 60909-3 IEC:2009 CONTENTS FOREWORD.5 1 Scope and object7 2 Normative references .8 3 Terms and definitions .8 4 Symbols .10 5 Calculation of currents during
20、two separate simultaneous line-to-earth short circuits .12 5.1 Initial symmetrical short-circuit current 12 5.1.1 Determination of ) (1 M and ) (2 M .12 5.1.2 Simple cases of two separate simultaneous line-to-earth short circuits.13 5.2 Peak short-circuit current, symmetrical short circuit breaking
21、current and steady-state short-circuit current .13 5.3 Distribution of the currents during two separate simultaneous line-to-earth short circuits14 6 Calculation of partial short-circuit currents flowing through earth in case of an unbalanced short circuit14 6.1 General .14 6.2 Line-to-earth short c
22、ircuit inside a station15 6.3 Line-to-earth short circuit outside a station16 6.4 Line-to-earth short circuit in the vicinity of a station.18 6.4.1 Earth potential U ETnat the tower n outside station B 19 6.4.2 Earth potential of station B during a line-to earth short circuit at the tower n 19 7 Red
23、uction factor for overhead lines with earth wires.20 8 Calculation of current distribution and reduction factor in case of cables with metallic sheath or shield earthed at both ends21 8.1 Overview.21 8.2 Three-core cable .22 8.2.1 Line-to-earth short circuit in station B 22 8.2.2 Line-to-earth short
24、 circuit on the cable between station A and station B23 8.3 Three single-core cables .26 8.3.1 Line-to-earth short circuit in station B 26 8.3.2 Line-to-earth short circuit on the cable between station A and station B26 Annex A (informative) Example for the calculation of two separate simultaneous l
25、ine- to-earth short-circuit currents30 Annex B (informative) Examples for the calculation of partial short-circuit currents through earth 33 Annex C (informative) Example for the calculation of the reduction factor r 1and the current distribution through earth in case of a three-core cable.43 Annex
26、D (informative) Example for the calculation of the reduction factor r 3and the current distribution through earth in case of three single-core cables48 60909-3 IEC:2009 3 Figure 1 Driving point impedance Z Pof an infinite chain, composed of the earth wire impedance QQ Z Zd = T and the footing resist
27、ance R Tof the towers, with equal distances d Tbetween the towers.9 Figure 2 Driving point impedance Z Pnof a finite chain with n towers, composed of the earth wire impedance T Q Q d Z Z = , the footing resistance R Tof the towers, with equal distances d Tbetween the towers and the earthing impedanc
28、e Z EBof station B from Equation (29)10 Figure 3 Characterisation of two separate simultaneous line-to earth short circuits and the currents “ kEE I .12 Figure 4 Partial short-circuit currents in case of a line-to-earth short circuit inside station B .15 Figure 5 Partial short-circuit currents in ca
29、se of a line-to-earth short circuit at a tower T of an overhead line 16 Figure 6 Distribution of the total current to earth ETtot I 17 Figure 7 Partial shortcircuit currents in the case of a line-to-earth short circuit at a tower n of an overhead line in the vicinity of station B.18 Figure 8 Reducti
30、on factor r for overhead lines with non-magnetic earth wires depending on soil resistivity .21 Figure 9 Reduction factor of three-core power cables 23 Figure 10 Reduction factors for three single-core power cables .27 Figure A.1 Two separate simultaneous line-to-earth short circuits on a single fed
31、overhead line (see Table 1) 30 Figure B.1 Line-to-earth short circuit inside station B System diagram for stations A, B and C 34 Figure B.2 Line-to-earth short circuit inside station B Positive-, negative- and zero- sequence systems with connections at the short-circuit location F within station B.3
32、4 Figure B.3 Line-to-earth short circuit outside stations B and C at the tower T of an overhead line System diagram for stations A, B and C.36 Figure B.4 Line-to-earth short circuit outside stations B and C at the tower T of an overhead line Positive-, negative- and zero-sequence systems with connec
33、tions at the short-circuit location F.37 Figure B.5 Earth potentials u ETn= U Etn /U ETwith U ET= 1,912 kV and u EBn= U Ebn /U EB with U EB= 0,972 kV, if the line-to-earth short circuit occurs at the towers n = 1, 2, 3, . in the vicinity of station B42 Figure C.1 Example for the calculation of the c
34、able reduction factor and the current distribution through earth in a 10-kV-network, U n= 10 kV; c = 1,1; f = 50 Hz 44 Figure C.2 Short-circuit currents and partial short-circuit currents through earth for the example in Figure C.1.45 Figure C.3 Example for the calculation of current distribution in
35、 a 10-kV-network with a short circuit on the cable between A and B (data given in C.2.1 and Figure C.1).46 Figure C.4 Line-to-earth short-circuit currents, partial currents in the shield and partial currents through earth47 Figure D.1 Example for the calculation of the reduction factor and the curre
36、nt distribution in case of three single-core cables and a line-to-earth short circuit in station B .49 Figure D.2 Positive-, negative- and zero-sequence system of the network in Figure D.1 with connections at the short-circuit location (station B) .50 Figure D.3 Current distribution for the network
37、in Figure D.1, depending on the length, , of the single-core cables between the stations A and B51 4 60909-3 IEC:2009 Figure D.4 Example for the calculation of the reduction factors 3 r and the current distribution in case of three single-core cables and a line-to-earth short circuit between the sta
38、tions A and B .52 Figure D.5 Positive-, negative- and zero-sequence system of the network in Figure D.4 with connections at the short-circuit location (anywhere between the stations A and B) 52 Figure D.6 Current distribution for the cable in Figure D.4 depending on A , R EF .54 Figure D.7 Current d
39、istribution for the cable in Figure D.4 depending on A , R EF= 5 56 Table 1 Calculation of initial line-to-earth short-circuit currents in simple cases 13 Table 2 Resistivity of the soil and equivalent earth penetration depth 20 Table C.1 Results for the example in Figure C.1 45 Table C.2 Results fo
40、r the example in Figure C.3, km 5 = l .47 Table C.3 Results for the example in Figure C.3, km 10 = l .47 60909-3 IEC:2009 5 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ SHORT-CIRCUIT CURRENTS IN THREE-PHASE AC SYSTEMS Part 3: Currents during two separate simultaneous line-to-earth short circuits and
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