Iec tr 60909 2 2008

IEC/TR 60909-2 Edition 2.0 2008-11 TECHNICAL REPORT IEC/TR 60909-2:2008(E) LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU Short-circuit currents in three-phase a.c systems – Part 2: Data of electrical equipment for short-circuit current calculations THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright © 2008 IEC, Geneva, Switzerland All rights reserved Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or IEC's member National Committee in the country of the requester If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local IEC member National Committee for further information IEC Central Office 3, rue de Varembé CH-1211 Geneva 20 Switzerland Email: inmail@iec.ch Web: www.iec.ch The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes International Standards for all electrical, electronic and related technologies About IEC publications The technical content of IEC publications is kept under constant review by the IEC Please make sure that you have the latest edition, a corrigenda or an amendment might have been published ƒ Catalogue of IEC publications: www.iec.ch/searchpub The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…) It also gives information on projects, withdrawn and replaced publications ƒ IEC Just Published: www.iec.ch/online_news/justpub Stay up to date on all new IEC publications Just Published details twice a month all new publications released Available on-line and also by email ƒ Electropedia: www.electropedia.org The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions in English and French, with equivalent terms in additional languages Also known as the International Electrotechnical Vocabulary online ƒ Customer Service Centre: www.iec.ch/webstore/custserv If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service Centre FAQ or contact us: Email: csc@iec.ch Tel.: +41 22 919 02 11 Fax: +41 22 919 03 00 LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU About the IEC IEC/TR 60909-2 Edition 2.0 2008-11 TECHNICAL REPORT LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU Short-circuit currents in three-phase a.c systems – Part 2: Data of electrical equipment for short-circuit current calculations INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 17.220.01; 29.240.20 ® Registered trademark of the International Electrotechnical Commission PRICE CODE X ISBN 2-8318-1016-1 –2– TR 60909-2 © IEC:2008(E) CONTENTS FOREWORD General 1.1 Scope and object 1.2 Normative references Data for electrical equipment General Data of typical synchronous machines .7 Data of typical two-winding, three-winding and auto-transformers 10 Data of typical overhead lines, single and double circuits 14 Data of typical high-voltage, medium-voltage and low-voltage cables 20 Data of typical asynchronous motors 35 Busbars 38 (informative) Information from National Committees 42 Bibliography 43 Figure – Subtransient reactance of synchronous machines 50 Hz and 60 Hz (Turbogenerators, salient pole generators, motors SM and condensers SC) Figure – Rated Voltage U rG and rated power factor cosϕ rG of synchronous machines (Turbo generators, salient pole generators, motors and condensers 50 Hz and 60 Hz) Figure – Unsaturated and saturated synchronous reactance of two-pole turbo generators 50 Hz and 60 Hz (relative values) Figure – Three-winding transformer (No of Table 3) 12 Figure – Rated short-circuit voltage u kr of unit transformers in power stations (ST) with or without on-load tap-changer 13 Figure – Rated short-circuit voltages u kr of network transformers 14 Figure – Positive-sequence reactance X ('1) = X L' of low-voltage and medium-voltage overhead lines 50 Hz, Cu or Al, with one circuit according to Equation (15) of IEC 60909-0 16 Figure – Positive-sequence reactance X ('1) = X L' of overhead lines 50 Hz (60 Hzvalues converted to 50 Hz) 19 Figure – Type of overhead lines 20 Figure 10 – Single-core cable 64 kV / 110 kV with lead sheath [4] 23 Figure 11 – Reduction factor depending on the inducing current for cables with one lead sheath and two overlapping steel tapes, f = 50 Hz [3] 35 Figure 12 – Reduction factor depending on the inducing current for cables with three lead sheaths and two overlapping steel tapes, f = 50 Hz [3] 35 Figure 13 – Ratio I LR /I rM of low-voltage and medium-voltage asynchronous motors, 50 Hz and 60 Hz 37 Figure 14 – Product cosϕrM x ηrM of low-voltage and medium-voltage motors, 50 Hz and 60 Hz 38 Figure 15 – Geometric mean distance g L1L1 = g L2L2 = g L3L3 of the main conductors 39 Figure 16 – Factor α and β for the calculation of X ('1) given in Equation (34) 40 LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Annex A TR 60909-2 © IEC:2008(E) –3– Table – Actual data of typical synchronous generators, motors and condensers Table – Actual data of typical two-winding transformers (NT: network; ST: power station) 10 Table – Actual data of typical three-winding transformers 11 Table – Actual data of typical autotransformers with and without tertiary winding 12 Table – Actual data of typical overhead lines 50 Hz and 60 Hz 18 Table – Actual data of typical electric cables 21 Table – Equations for the positive-sequence and the zero-sequence impedance of cables 22 Table – Single-core cables 64/110 kV, 2XK2Y, × × 240 200 rm, Cu with lead sheath 24 Table 10 – 20-kV-cables N2XS2Y 26 Table 11 – Positive-sequence and zero-sequence impedance of four low-voltage single-core cables NYY × × q n (Case No 2a in Table 7) 27 Table 12 – Low-voltage cable NYY 29 Table 13 – Low-voltage cable NYY with three and a half copper conductors 30 Table 14 – Low-voltage cable NYCWY with four copper conductors 32 Table 15 – Low-voltage cable NYCWY 33 Table 16 – Actual data of typical asynchronous motors 36 Table 17 – Actual data of distribution busbars 38 Table 18 – Example for the calculation of X ('1) for busbars using Figures 15 and 16 41 Table A.1 – Information received from National Committees 42 LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU Table – 10-kV-cables N2XS2Y 25 –4– TR 60909-2 © IEC:2008(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ SHORT-CIRCUIT CURRENTS IN THREE-PHASE AC SYSTEMS – Part 2: Data of electrical equipment for short-circuit current calculations FOREWORD 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication 6) All users should ensure that they have the latest edition of this publication 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications 8) Attention is drawn to the Normative references cited in this publication Use of the referenced publications is indispensable for the correct application of this publication 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights IEC shall not be held responsible for identifying any or all such patent rights The main task of IEC technical committees is to prepare International Standards However, a technical committee may propose the publication of a technical report when it has collected data of a different kind from that which is normally published as an International Standard, for example "state of the art" IEC 60909-2, which is a technical report, has been prepared by IEC technical committee 73: Short-circuit currents This technical report is to be read in conjunction with IEC 60909-0 and IEC 60909-3 This second edition cancels and replaces the first edition published in 1992 This edition constitutes a technical revision The significant technical changes with respect to the previous edition are as follows: LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees) The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”) Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work International, governmental and nongovernmental organizations liaising with the IEC also participate in this preparation IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations TR 60909-2 © IEC:2008(E) –5– – Subclause 2.5 gives equations and examples for the calculation of the positive-, the negative and the zero-sequence impedances and reduction factors for high-, medium and low-voltage cables with sheaths and shields earthed at both ends – Subclause 2.7 gives equations and figures for the calculation of the positive-sequence impedances of busbar configurations The text of this technical report is based on the following documents: Enquiry draft Report on voting 73/142/DTR 73/145/RVC Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table A list of all parts of the IEC 60909, published under the general title Short-circuit currents in three-phase a.c systems , can be found on the IEC website The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication At this date, the publication will be • • • • reconfirmed, withdrawn, replaced by a revised edition, or amended A bilingual version of this publication may be issued at a later date LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU This publication has been drafted in accordance with the ISO/IEC Directives, Part –6– TR 60909-2 © IEC:2008(E) SHORT-CIRCUIT CURRENTS IN THREE-PHASE AC SYSTEMS – Part 2: Data of electrical equipment for short-circuit current calculations 1.1 General Scope and object Generally, electrical equipment data are given by the manufacturers on the name plate or by the electricity supplier In some cases, however, the data may not be available The data in this report may be applied for calculating short-circuit currents in low-voltage networks if they are in accordance with typical equipment employed in the user’s country The collected data and their evaluation may be used for medium- or high-voltage planning purposes and also for comparison with data given by manufacturers or electricity suppliers For overhead lines and cables the electrical data may in some cases also be calculated from the physical dimensions and the material following the equations given in this report Thus this technical report is an addition to IEC 60909-0 It does not, however, change the basis for the standardized calculation procedure given in IEC 60909-0 and IEC 60909-3 1.2 Normative references The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies IEC 60909-0:2001, Short-circuit currents in three-phase a.c systems – Part 0: Calculation of currents IEC 60909-3:- 1, Short-circuit currents in three-phase a.c systems – Part 3: Currents du-ring two separate simultaneous line-to-earth short-circuit currents and partial short-circuit currents flowing through earth 2.1 Data for electrical equipment General The data presented are necessary for the calculation of short-circuit currents They are sometimes presented in the form of curve sheets and sometimes in the form of examples in tables In the case of easy equations they are given for the calculations of positive-sequence and zero-sequence short-circuit impedances for overhead lines and cables ————————— To be published LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU This part of IEC 60909 comprises data of electrical equipment collected from different countries to be used when necessary for the calculation of short-circuit currents in accordance with IEC 60909-0 TR 60909-2 © IEC:2008(E) –7– In all, 15 National Committees provided information in response to a questionnaire sent out before the first edition of this report Table of the first edition of this report is given in Annex A In some cases, average values or characteristic trends as function of rated power, rated voltage, etc are given 2.2 Data of typical synchronous machines Characteristic data of synchronous machines are listed in Table The reactances are given as relative values related to Z rG = U rG / S rG (see IEC 60909-0) Sometimes they are given in % Table – Actual data of typical synchronous generators, motors and condensers No Type a) Rated Rated voltage Power and factor appar power deviation b) SrG U rG ± pG cos ϕrG Relative values of reactances and d.c time constant xd" Note x( ) x( ) xd xdsat TDC c) d) e) f) g) s National Committee - MVA kV % - - - - - - TG2 64 13,8 ±5 0,85 0,179 0,170 0,104 1,87 1,87 0,220 60 Hz TG2 100 10,5 ±5 0,80 0,134 - - 1,77 1,45 0,246 50 Hz Germany TG2 125 10,5 ±5 0,80 0,160 0,180 0,08 2,13 1,87 0,460 50 Hz ex-GDR TG2 180 10,5 ±5 0,90 0,250 0,230 0,14 1,83 1,77 0,480 50 Hz Austria TG2 353 18,0 ±5 0,85 0,167 0,204 0,089 2,26 2,17 0,194 50 Hz China TG2 388,9 17,5 ±5 0,90 0,203 0,202 0,099 2,42 2,19 0,250 50 Hz Australia SG14 48 10 ±5 0,90 0,16 0,17 0,05 0,78 - 0,16 50 Hz Italy SG20 290 18,0 ±5 0,90 0,22 0,22 0,14 1,03 0,96 0,36 60 Hz Japan SM2 1,45 10 +5 0,90 0,166 0,166 0,046 1,63 - 0,04 50 Hz ex-USSR USA –10 3,40 4,0 ±5 0,80 0,249 0,303 - 2,675 2,675 0,116 60 Hz USA 11 SC10 40 13,8 ±5 0,119 0,129 - 1,33 1,33 0,1425 60 Hz USA 12 SC6 100 10,5 ±5 0,20 0,25 0,095 1,78 1,60 a) TG2: Two-pole turbo generator c) Negative-sequence reactance SG: Salient pole generator d) Zero-sequence reactance SM: Synchronous motor e) Unsaturated synchronous reactance SC: Salient pole synchronous condenser f) Saturated synchronous reactance pG ⎞ ⎛ ⎟ U G = U rG ⎜⎜1 ± 100 % ⎟⎠ ⎝ g) DC time constant for a three-phase terminal short circuit 10 b) SM3 0,57 50 Hz exCzechoslovakia LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU In Figure the sub-transient reactances of synchronous machines (generators, motors and condensers) in the direct axis of 50 Hz or 60 Hz machines are plotted as a function of the rated power TR 60909-2 © IEC:2008(E) –8– % MVA 100 80 60 Australia Czechoslovakia ex-Czechoslovakia Italy Austria ex-GDR Japan Bulgaria Germany Norway China Hungary USA x '' d = x '' d = x '' d = SM 40 ,3 ,2 ,1 20 x''d100 SrG SM SM x ''d= 0,08 SM SM SM SM SM 0,8 0,6 0,4 SC 0,2 0,1 0,08 0,06 0,04 0,02 0,01 0,1 0,2 0,4 0,6 10 20 40 60 100 200 MVA 600 000 000 SrG IEC 2028/08 Figure – Subtransient reactance of synchronous machines 50 Hz and 60 Hz (Turbogenerators, salient pole generators, motors SM and condensers SC) In Figure the rated voltages and power factors of 50 Hz or 60 Hz synchronous machines (generators, motors) are plotted as a function of the rated power In Figure unsaturated and saturated ( x dsat / x d ) synchronous reactances for 50 Hz and 60 Hz turbogenerators, used for the calculation of the steady state short-circuit current, are plotted as a function of the rated power Data are also given for the zero-sequence reactance It is recommended that the relationship X (0) / X d" = 0,5 is used LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU 10 TR 60909-2 © IEC:2008(E) – 32 – ' =ω Z NS μ0 + jω μ0 2π ln δ rSm ; Reduction factor: ( ) ' ' ' ' ' ' ' Z N Z LS + Z S Z LN − Z NS Z LN + Z LS r = 1− ⋅ ' ' '2 ZN ZS − Z NS (29) Table 14 gives the results found with Equations (26) to (29) for cables NYCWY with four equal conductors The data rL , RL' , rN = rL , RN' = RL' and d = dLN are the same as in Table 12a qn Da a) mm rSm RS' b) c) R(' 0)NS X (' 0)NS R(' )NSE X (' )NSE ' R(1)NS ' X (1)NS ' R(1)NS ' X (1)NS Ω/km - - - - - Z (' 1)NS (see Table 12a) r mm mm × 25/16rST 30 13,2 1,12 0,727+j 0,0878 2,82 2,19 2,23 7,90 0,50 × 35/16 sST 29 12,7 1,12 0,524+j0,0850 3,05 2,41 2,48 6,51 0,42 × 50/25 sST 34 15,0 0,714 0,387+j0,0846 2,96 2,28 2,57 4,60 0,32 × 70/35 sST 38 16,9 0,510 0,268+j0,0824 3,01 2,30 2,69 3,54 0,24 × 95/50 sST 43 19,2 0,357 0,193+j0,0820 3,02 2,25 2,76 2,92 0,18 × 120/70 sST 47 21,1 0,255 0,153+j0,0805 2,99 2,15 2,77 2,56 0,15 × 150/70 sST 51 22,9 0,255 0,124+j0,0802 3,19 2,31 2,94 2,61 0,14 × 185/95 sST 57 25,7 0,188 0,0991+j0,0803 3,22 2,21 2,99 2,40 0,11 × 240/120 sST 64 29,0 0,149 0,0754+j0,0799 3,42 2,19 3,18 2,30 0,10 The data rL , a) See Table NOTE b) rSm c) Ω/km RL' , rN = rL , RN' = RL' and d are given in Table 12a = 0,5(rSa + rSi ) κ S = 56 Sm/mm Cable with three conductors N(A)YCWY: Z (' 1)S = RL' + jω μ0 ⎛ d ⎜⎜ + ln 2π ⎝ rL ⎞ ⎟⎟ ⎠ [(see Equation (18)] (30) Current return through the concentric copper conductor (shield S): Z (' )S = RL' + RS' + jω ⎛ μ0 ⎜ 2π ⎜⎜ ⎝ + ln rSm rL d ⎞ ⎟ ⎟ ⎟ ⎠ with the medium radius of the shield or sheath rSm = 0,5( rSa + rSi ) Current return through the concentric copper conductor (shield S) and the earth E: (31) LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU Table 14 – Low-voltage cable NYCWY with four copper conductors TR 60909-2 © IEC:2008(E) – 33 – Z (' )SE = RL' + 3ω μ0 ⎛ + jω μ0 ⎜ r= Reduction factor: δ + ln 2π ⎜⎜ r d2 L ⎝ RS' +ω μ0 RS' + jω ⎛ μ0 μ δ ⎞ ⎟ ⎜⎜ ω + jω ln ⎞ 2π rSm ⎟⎠ ⎟ ⎝ ⎟−3 ' μ μ δ ⎟ RS + ω + jω ln ⎠ 2π rSm μ0 2π ln (32) (33) δ rSm Table 15 – Low-voltage cable NYCWY d Z (' 1)S R(' 0)S X (' 0)S R(' 0)SE X (' 0)SE d) e) Equation (30) R('1)S X ('1)S R('1)S X ('1)S mm Ω/km mm Ω/km - - - - - 0,727 11,6 1,12 9,11 0,727+j 0,0807 5,62 1,56 2,39 19,26 0,82 3,82 0,524 11,1 1,12 10,3 0,524+j 0,0780 7,41 1,18 2,93 19,50 0,82 × 50sST/25 4,54 0,387 12,9 0,714 12,2 0,387+j 0,0778 6,53 1,14 3,73 13,96 0,69 × 70sST/35 5,40 0,268 15,0 0,510 13,8 0,268+j 0,0747 6,71 1,21 4,66 10,34 0,57 × 95sST50 6,30 0,193 17,3 0,357 16,1 0,193+j 0,0747 6,55 1,18 5,28 6,71 0,45 × 120sST/70 7,10 0,153 18,2 0,255 17,7 0,153+j 0,0731 6,00 1,07 5,30 4,34 0,34 × 150sST/70 7,95 0,124 20,6 0,255 19,9 0,124+j 0,0734 7,17 1,10 6,29 4,37 0,35 × 185sST/95 8,80 0,0991 22,9 0,188 22,0 0,0991+j 0,0733 6,69 1,10 6,18 3,03 0,27 × 240sST/120 10,05 0,0754 25,7 0,149 24,8 0,0754+j 0,0725 6,93 1,09 6,56 2,37 0,22 × 300sST/150 11,25 0,0601 28,5 0,119 27,8 0,0601+j0,0725 6,94 1,06 6,68 1.91 0,18 a) See Table 12a b) See Table 12a c) rSm = 0,5 rSa + rSi ) rL a) RL' b) rSm c) mm Ω/km × 25rST/16 3,24 × 35sST/16 qn mm ( Sm/mm d) κ S = 56 e) d = d L1L2 d L1L3 d L2L3 RS' r LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU a) with three copper conductors TR 60909-2 © IEC:2008(E) – 34 – b) with three aluminium conductors R(' )S X (' 0)S R(' )SE X (' )SE Equation (30) R('1)S X ('1)S R('1)S X ('1)S mm Ω/km - - - - - 0,357 10,7 0,641+j 0,0775 2,67 1,34 2,31 6,59 0,44 13,7 0,255 12,1 0,443+j 0,0749 2,73 1,31 2,50 4,45 0,33 0,320 15,8 0,188 14,1 0,320+j 0,0749 2,76 1,29 2,62 3,12 0,26 6,18 0,253 17,2 0,149 15,4 0,253+j 0,0731 2,77 1,29 2,66 2,51 0,21 × 150s/150 6,91 0,206 19,0 0,119 17,3 0,206+j 0,0734 2,73 1,24 2,66 2,05 0,17 × 185s/185 7,67 0,164 20,0 0,0965 19,2 0,164+j 0,0734 2,77 1,11 2,71 1,62 0,14 RL' rSm b) c) d) 5) mm Ω/km mm Ω/km × 50s/50 4,00 0,641 12,3 × 70s/70 4,72 0,443 × 95s/95 5,50 × 120s/120 qn rL a) mm ( d Z (' 1)S r + rSi ) Sm/mm d) κ S = 56 e) d = d L1L2 d L1L3 d L2L3 Type C: l Belted cable with three copper or aluminium (A) conductors, a massimpregnated paper insulation for conductors (and belt), a smooth extruded aluminium sheath (KL), protective covering with an embedded layer of elastomer tape or plastic film (E) and a sheath of thermoplastic material based on PVC (Y): N(A)KLEY Equations (30) to (33) are valid for the positive-sequence, the zero-sequence impedance and the reduction factor as for cables of type B with three conductors Cables N(A)KLEY are used in former times for local networks The aluminium sheath then was applied as a neutral conductor N or PEN [3] Type D: Cable with four (or three and a half) copper or aluminium (A) conductors, a mass-impregnated paper insulation for conductors (and belt), lead sheath (K) with steel tape armouring (B) and an outer serving of fibrous material (A): N(A)KBA These cables are used in former times in low-voltage distribution networks, if the additional earthing by the lead-sheath was necessary [3] Calculation of the positive-sequence, the zero-sequence impedance and the reduction factor is possible, when neglecting the steel tape armouring, with Equations (26) to (29) in case of four (or three and a half) conductors respectively Equations (30) to (33) in case of four conductors The reduction factor in case of a lead sheath and the armouring with at least two overlapping steel tapes is found by measurement [3] The results published in [3] are given in the Figures 11 and 12 for information LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU a) See Table 12b b) See Table 12b c) rSm = 0,5 rSa RS' TR 60909-2 © IEC:2008(E) – 35 – Figure 11 – Reduction factor depending on the inducing current for cables with one lead sheath and two overlapping steel tapes, f = 50 Hz [3] IEC 2039/08 Figure 12 – Reduction factor depending on the inducing current for cables with three lead sheaths and two overlapping steel tapes, f = 50 Hz [3] 2.6 Data of typical asynchronous motors The ratio locked-rotor current to rated current ILR / I rM is different for low- and mediumvoltage motors For low-voltage motors the average value is approximately 6,7 in the range kW to 300 kW per pair of poles The average value for medium-voltage motors is approximately 5,5 in the range 30 kW to MW per pair of poles In Table 16 actual data of asynchronous motors are given LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU IEC 2038/08 TR 60909-2 © IEC:2008(E) – 36 – Table 16 – Actual data of typical asynchronous motors No Rated Rated Rated power voltage current Power factor – – 1/min – 0,89 0,92 7,14 2950 – Bulgaria 6,4 – 0,013 exCzechoslovakia 5,3 2973 0,05 Germany cos ϕrM kW kV A 45 0,38 80 0,38 370 250 6,0 29 Country – I rM 200 Rotation Number of DC Time pair of constant speed poles nr TDC p ηrM U rM Ratio I LR I rM PrM Efficien cy (rated) cos ϕrM × ηrM = 0,82 0,89 0,94 s 500 6,0 62 0,83 0,94283 5,8 741 0,053 GRD 000 6,0 121 0,85 0,985 5,0 590 0,031 ex-USSR 150 6,0 380 5,2 - 0,064 exCzechoslovakia 000 6,0 660 0,90 0,972 5,5 1490 - Italy 315 6,0 36,5 0,88 0,942 6,2 1794 - Norway, 60 Hz 000 6,6 595 0,91 0,969 4,5 1776 0,055 Japan, 60 Hz 10 698 6,6 963 0,917 0,961 6,23 1190 0,0968 USA, 60 Hz cos ϕrM × ηrM = 0,80 In Figure 13 the ratio ILR / I rM and in Figure 14 the product cos ϕrM × ηrM of power factor and efficiency is plotted as a function of the active power per pair of poles PrM / p LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU TR 60909-2 © IEC:2008(E) – 37 – Australia Denmark Italy Bulgaria ex-GDR Japan China Germany Norway ex-Czechoslovakia Czechoslovakia Hungary USA Medium values ILR IrM Medium-voltage motors Low-voltage motors Low-voltage motors Medium-voltage motors (10 kW) 0,002 0,004 0,01 (100 kW) 0,02 0,04 0,06 0,1 (1 000 kW) 0,2 0,4 0,6 10 MW Active power of the motor per pair of poles m = P rM /p Low-voltage motors Figure 13 – Ratio I LR /I rM of low-voltage and medium-voltage asynchronous motors, 50 Hz and 60 Hz IEC 2040/08 LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU TR 60909-2 © IEC:2008(E) – 38 – Australia ex-GDR Japan Bulgaria Germany Norway China Hungary USA Denmark Italy ex-USSR 1,0 0,9 cos ϕrM · ηr 0,8 0,7 p=6 Low-voltage motors 0,5 Medium-voltage motors 0,002 0,004 0,006 0,01 0,02 0,04 0,06 0,1 0,2 0,4 0,6 22 10 MW IEC 2041/08 Low-voltage motors Figure 14 – Product cosϕrM x ηrM of low-voltage and medium-voltage motors, 50 Hz and 60 Hz 2.7 Busbars Collected data of busbars are given in Table 17 Table 17 – Actual data of distribution busbars No Rated voltage Rated current Ur Ir Sheath Current material return Conductors Number Material b) Cross section kV A - - mm - 0,38/ 250 Al 120 Al 600 Al 280 200 3×2 Al 650 Positive-sequence impedance Zero-sequence impedance Z '(1) = R('1) + jX ('1) Z '(0 ) = R(' 0) + jX (' ) Ω/km Ω/km S+E 0,0380+j0,0163 0,0882+j0,0689 exUSSR Al S+E 0,0297+j0,0143 0,0672+j0,0555 exUSSR Al S+E 0,0101+j0,00495 0,0735+j0,0392 exUSSR 0,66 (0,40/ 0,69) a) Country a) Split bar × 600 A b) Current return through sheath (S) and earth (E) A calculation of the medium positive-sequence reactance per unit length of busbars (without sheath or shielding) with one, two or three parallel bars (Cu or Al) per main conductor L1, L2 or L3 is possible with the following equation, using the theory of geometric mean distance [5]: LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU 0,6 TR 60909-2 © IEC:2008(E) X ('1) =ω – 39 – μ0 2π ln gL1L2 gL1L3 gL1L1 =ω μ0 2π ln (α dL1L2 )2 ( β dL1L3 ) (34) gL1L1 Approximations for the geometric mean distance g L1L1 are given in Figure 15 IEC g L1L1 = (0,74+0,226 × n ) × a Figure 15 – Geometric mean distance g L1L1 g L1L1 = (1,218+0,227 × n ) × a = g L2L2 = g L3L3 of the main conductors The factors α = g L1L2 / d L1L2 and β = g L1L3 / dL1L3 are given in the Figures 16a, 16b, 16c for one, two or three bars per main conductor (Figure 15), depending on the distance d L1L2 ( d L1L3 = 2· d L1L2 ) and the factor n = 2, 4, 6, (see Figure 15) IEC 2043/08 a) For one bar per main conductor; a = 10 mm LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU g L1L1 = (0,23+0,222 × n ) × a 2042/08 – 40 – TR 60909-2 © IEC:2008(E) b) For two bars per main conductor; a = 10 mm IEC 2045/08 c) For three bars per main conductor; a = 10 mm Figure 16 – Factor α and β for the calculation of X ('1) given in Equation (34) LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU IEC 2044/08 TR 60909-2 © IEC:2008(E) – 41 – Table 18 – Example for the calculation of X ('1) for busbars using Figures 15 and 16 Three-phase 50 Hz, L1, a.c busbar, L2, L3 Cu, a × n × a (Fig 15) mm qn mm g L1L1 (Figure 15) g L1L2 = α × d L1L2 60 × 10 × 60 × 10 × 60 × 10 600 200 800 cm 1,565 2,099 2,583 cm 1,071 × = 6,426 1,050 × = 6,300 1,013 × = 6,078 cm 1,022 ×12 = 12,264 1,013 × 12 = 12,156 1,002 × 12 = 12,024 0,102 0,083 0,068 (Figure 16) g L1L3 = β × d L1L3 X ('1) (Equation 34) Ω/km LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU (Figure 16) TR 60909-2 © IEC:2008(E) – 42 – Annex A (informative) Information from National Committees Data given in the Tables 1, 2, 3, 4, 5, 6, 16 and 17 of this publication are collected from different countries In all, 15 National Committees provided information for the first edition of IEC/TR 60909-2: 1992 Information received at that time is listed in the following Table A.1 (see Table of IEC/TR 60909-2: 1992) Table A.1 – Information received from National Committees Committee Number of answers to questionnaire tables Australia 3 3 3 Austria 10 11 - Bulgaria 15 6 14 11 28 China 3 3 3 ex-Czechoslovakia - 68 Denmark 18 15 - ex-GDR 23 28 - 20 Germany 21 26 13 19 Hungary 16 9 Italy 25 16 26 11 Japan 12 10 7 Norway 10 10 - 11 - - - USA 110 10 - - 10 20 ex-USSR 12 - 10 255 188 51 57 113 101 204 UK Total LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU National TR 60909-2 © IEC:2008(E) – 43 – Bibliography Balzer, G., Impedanzmessungen in Niederspannungsnetzen zur Bestimmung der Kurzschlstrưme (Measurement of impedances in low-voltage networks for the determi-nation of short-circuit currents) Diss TH Darmstadt 1977 [2] Meyer, E P., Stromrückleitung über das Erdreich, Impedanzen und induktive Beeinflussung bei Leitern endlicher Länge (Current return through the earth, impedances and inductive interference in the case of conductors with limited length) Diss TH Darmstadt 1982 [3] Heinhold, L., Kabel und Leitungen für Starkstrom , Part 1:1987, Part 2:1989 Siemens Aktiengesellschaft [4] NEXANS, Energy Networks Germany Insulated Cables for High and Extra High Voltage Nexans Deutschland Industries AG & Co KG, 2000 [5] Oeding, D., Oswald, B R., Elektrische Kraftwerke und Netze , Edition: Springer 2004 [6] IEC 60038: 2002, IEC standard voltages [7] IEC/TR 60909-1:2002, Short-circuit currents in three-phase a.c systems – Part 1: Factors for the calculation of short-circuit currents according to IEC 60909-0 [8] IEC/TR 60909-4:2000, Short-circuit currents in three-phase a.c systems – Part 4: Examples for the calculation of short-circuit currents _ LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU [1] LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU ELECTROTECHNICAL COMMISSION 3, rue de Varembé PO Box 131 CH-1211 Geneva 20 Switzerland Tel: + 41 22 919 02 11 Fax: + 41 22 919 03 00 info@iec.ch www.iec.ch LICENSED TO MECON Limited - RANCHI/BANGALORE FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU INTERNATIONAL