IEC 60909-0:2016 is applicable to the calculation of short-circuit currents in low-voltage three-phase AC systems, and in high-voltage three-phase AC systems, operating at a nominal frequency of 50 Hz or 60 Hz. It establishes a general, practicable and concise procedure leading to results which are generally of acceptable accuracy and deals with the calculation of short-circuit currents in the case of balanced or unbalanced short circuits. This second edition cancels and replaces the first edition published in 2001. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: – contribution of windpower station units to the short-circuit current; – contribution of power station units with ful size converters to the short-circuit current; – new document structure. This publication is to be read in conjunction with \/2, \/2, \/2 and \/2.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 119<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 122<\/td>\n | FOREWORD <\/td>\n<\/tr>\n | ||||||
| 124<\/td>\n | 1 Scope <\/td>\n<\/tr>\n | ||||||
| 125<\/td>\n | 2 Normative references 3 Terms and definitions <\/td>\n<\/tr>\n | ||||||
| 130<\/td>\n | 4 Symbols, subscripts and superscripts 4.1 General 4.2 Symbols <\/td>\n<\/tr>\n | ||||||
| 132<\/td>\n | 4.3 Subscripts <\/td>\n<\/tr>\n | ||||||
| 133<\/td>\n | 4.4 Superscripts 5 Characteristics of short-circuit currents: calculating method 5.1 General <\/td>\n<\/tr>\n | ||||||
| 134<\/td>\n | Figures Figure 1 \u2013 Short-circuit current of a far-from-generator short circuit with constant AC component (schematic diagram) <\/td>\n<\/tr>\n | ||||||
| 135<\/td>\n | Figure 2 \u2013 Short-circuit current of a near-to-generator short-circuit with decaying AC component (schematic diagram) <\/td>\n<\/tr>\n | ||||||
| 136<\/td>\n | 5.2 Calculation assumptions Figure 3 \u2013 Characterization of short-circuits and their currents <\/td>\n<\/tr>\n | ||||||
| 137<\/td>\n | 5.3 Method of calculation 5.3.1 Equivalent voltage source at the short-circuit location <\/td>\n<\/tr>\n | ||||||
| 138<\/td>\n | Figure 4 \u2013 Illustration for calculating the initial symmetrical short-circuit current in compliance with the procedure for the equivalent voltage source <\/td>\n<\/tr>\n | ||||||
| 139<\/td>\n | 5.3.2 Symmetrical components Tables Table 1 \u2013 Voltage factor c <\/td>\n<\/tr>\n | ||||||
| 140<\/td>\n | 6 Short-circuit impedances of electrical equipment 6.1 General 6.2 Network feeders <\/td>\n<\/tr>\n | ||||||
| 141<\/td>\n | Figure 5 \u2013 System diagram and equivalent circuit diagram for network feeders <\/td>\n<\/tr>\n | ||||||
| 142<\/td>\n | 6.3 Transformers 6.3.1 Two-winding transformers 6.3.2 Three-winding transformers <\/td>\n<\/tr>\n | ||||||
| 144<\/td>\n | 6.3.3 Impedance correction factors for two- and three-winding network transformers Figure 6 \u2013 Three-winding transformer (example) <\/td>\n<\/tr>\n | ||||||
| 145<\/td>\n | 6.4 Overhead lines and cables <\/td>\n<\/tr>\n | ||||||
| 146<\/td>\n | 6.5 Short-circuit current-limiting reactors 6.6 Synchronous machines 6.6.1 Synchronous generators <\/td>\n<\/tr>\n | ||||||
| 148<\/td>\n | 6.6.2 Synchronous compensators and motors 6.7 Power station units 6.7.1 Power station units with on-load tap-changer <\/td>\n<\/tr>\n | ||||||
| 149<\/td>\n | 6.7.2 Power station units without on-load tap-changer <\/td>\n<\/tr>\n | ||||||
| 150<\/td>\n | 6.8 Wind power station units 6.8.1 General 6.8.2 Wind power station units with asynchronous generator <\/td>\n<\/tr>\n | ||||||
| 151<\/td>\n | 6.8.3 Wind power station units with doubly fed asynchronous generator <\/td>\n<\/tr>\n | ||||||
| 152<\/td>\n | 6.9 Power station units with full size converter 6.10 Asynchronous motors <\/td>\n<\/tr>\n | ||||||
| 153<\/td>\n | 6.11 Static converter fed drives 6.12 Capacitors and non-rotating loads 7 Calculation of initial short-circuit current 7.1 General 7.1.1 Overview <\/td>\n<\/tr>\n | ||||||
| 154<\/td>\n | Table 2 \u2013 Importance of short-circuit currents <\/td>\n<\/tr>\n | ||||||
| 155<\/td>\n | Figure 7 \u2013 Diagram to determine the short-circuit type (Figure 3) for the highest initial short-circuit current referred to the initial three-phase short-circuit current when the impedance angles of the sequence impedances Z(1), Z(2), Z(0) are identical <\/td>\n<\/tr>\n | ||||||
| 157<\/td>\n | Figure 8 \u2013 Examples of single-fed short-circuits Figure 9 \u2013 Example of a multiple single-fed short circuit <\/td>\n<\/tr>\n | ||||||
| 158<\/td>\n | 7.1.2 Maximum and minimum short-circuit currents Figure 10 \u2013 Example of multiple-fed short circuit <\/td>\n<\/tr>\n | ||||||
| 159<\/td>\n | 7.1.3 Contribution of asynchronous motors to the short-circuit current <\/td>\n<\/tr>\n | ||||||
| 160<\/td>\n | 7.2 Three-phase initial short-circuit current 7.2.1 General <\/td>\n<\/tr>\n | ||||||
| 161<\/td>\n | 7.2.2 Short-circuit currents inside a power station unit with on-load tap-changer <\/td>\n<\/tr>\n | ||||||
| 162<\/td>\n | Figure 11 \u2013 Short-circuit currents and partial short-circuit currents for three-phase short circuits between generator and unit transformer with or without on-load tap-changer, or at the connection to the auxiliary transformer of a power station unit and at the auxiliary busbar A <\/td>\n<\/tr>\n | ||||||
| 163<\/td>\n | 7.2.3 Short-circuit currents inside a power station unit without on-load tap-changer <\/td>\n<\/tr>\n | ||||||
| 164<\/td>\n | 7.3 Line-to-line short circuit 7.4 Line-to-line short circuit with earth connection <\/td>\n<\/tr>\n | ||||||
| 166<\/td>\n | 7.5 Line-to-earth short circuit 8 Calculation of peak short-circuit current 8.1 Three-phase short circuit 8.1.1 Single-fed and multiple single-fed short circuits <\/td>\n<\/tr>\n | ||||||
| 167<\/td>\n | Figure 12 \u2013 Factor \u03ba for series circuit as a function of ratio R\/X or X\/R <\/td>\n<\/tr>\n | ||||||
| 168<\/td>\n | 8.1.2 Multiple-fed short circuit <\/td>\n<\/tr>\n | ||||||
| 169<\/td>\n | 8.2 Line-to-line short circuit 8.3 Line-to-line short circuit with earth connection 8.4 Line-to-earth short circuit <\/td>\n<\/tr>\n | ||||||
| 170<\/td>\n | 9 Calculation of symmetrical breaking current 9.1 Three-phase short circuit 9.1.1 Symmetrical breaking current of synchronous machines <\/td>\n<\/tr>\n | ||||||
| 171<\/td>\n | 9.1.2 Symmetrical breaking current of asynchronous machines Figure 13 \u2013 Factor \u03bc for calculation of short-circuit breaking current Ib <\/td>\n<\/tr>\n | ||||||
| 172<\/td>\n | 9.1.3 Symmetrical breaking current of power station units with doubly fed asynchronous generator 9.1.4 Symmetrical breaking current of power station units with full size converter Figure 14 \u2013 Factor q for the calculation of the symmetrical short-circuit breaking current of asynchronous motors <\/td>\n<\/tr>\n | ||||||
| 173<\/td>\n | 9.1.5 Symmetrical breaking current of network feeder 9.1.6 Symmetrical breaking current in case of multiple single-fed short-circuits 9.1.7 Symmetrical breaking current in case of multiple-fed short circuits <\/td>\n<\/tr>\n | ||||||
| 174<\/td>\n | 9.2 Unbalanced short-circuits 10 DC component of the short-circuit current <\/td>\n<\/tr>\n | ||||||
| 175<\/td>\n | 11 Calculation of steady-state short-circuit current 11.1 General 11.2 Three-phase short circuit 11.2.1 Steady-state short-circuit current of one synchronous generator or one power station unit <\/td>\n<\/tr>\n | ||||||
| 177<\/td>\n | Figure 15 \u2013 Factors \u03bbmin and \u03bbmax factors for cylindrical rotor generators Figure 16 \u2013 Factors \u03bbmin and \u03bbmax for salient-pole generators <\/td>\n<\/tr>\n | ||||||
| 178<\/td>\n | 11.2.2 Steady-state short-circuit current of asynchronous motor or generator 11.2.3 Steady-state short-circuit current of wind power station unit with doubly fed asynchronous generator 11.2.4 Steady-state short-circuit current of wind power station unit with full size converter 11.2.5 Steady-state short-circuit current of network feeder 11.2.6 Steady-state short-circuit current in case of multiple single-fed short circuits <\/td>\n<\/tr>\n | ||||||
| 179<\/td>\n | 11.2.7 Steady-state short-circuit current in case of multiple-fed short circuits 11.3 Unbalanced short circuits 12 Short circuits at the low-voltage side of transformers, if one line conductor is interrupted at the high-voltage side <\/td>\n<\/tr>\n | ||||||
| 180<\/td>\n | Figure 17 \u2013 Transformer secondary short-circuits, if one line (fuse) is opened on the high-voltage side of a transformer Dyn5 <\/td>\n<\/tr>\n | ||||||
| 181<\/td>\n | 13 Terminal short circuit of asynchronous motors Table 3 \u2013 Factors \u03b1 and \u03b2 for the calculation of short-circuit currents with Formula (96), rated transformation ratio tr = UrTHV\/UrTLV <\/td>\n<\/tr>\n | ||||||
| 182<\/td>\n | 14 Joule integral and thermal equivalent short-circuit current Table 4 \u2013 Calculation of short-circuit currents of asynchronous motors in the case of a short circuit at the terminals <\/td>\n<\/tr>\n | ||||||
| 183<\/td>\n | Figure 18 \u2013 Factor m for the heat effect of the DC component of the short-circuit current (for programming, the formula to calculate m is given in Annex A) <\/td>\n<\/tr>\n | ||||||
| 184<\/td>\n | Figure 19 \u2013 Factor n for the heat effect of the AC component of the short-circuit current (for programming, the formula to calculate n is given in Annex A) <\/td>\n<\/tr>\n | ||||||
| 185<\/td>\n | Annex A (normative) Formulas for the calculation of the factors m and n <\/td>\n<\/tr>\n | ||||||
| 186<\/td>\n | Annex B (informative) Nodal admittance and nodal impedance matrices <\/td>\n<\/tr>\n | ||||||
| 187<\/td>\n | Figure B.1 \u2013 Formulation of the nodal admittance matrix <\/td>\n<\/tr>\n | ||||||
| 188<\/td>\n | Figure B.2 \u2013 Example Table B.1 \u2013 Impedances of electrical equipment referred to the 110 kV side <\/td>\n<\/tr>\n | ||||||
| 190<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Tracked Changes. Short-circuit currents in three-phase a.c. systems – Calculation of currents<\/b><\/p>\n |