BS EN 60909-0:2016 – TC:2020 Edition
$280.87
Tracked Changes. Short-circuit currents in three-phase a.c. systems – Calculation of currents
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 193 |
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.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 119 | English CONTENTS |
| 122 | FOREWORD |
| 124 | 1 Scope |
| 125 | 2 Normative references 3 Terms and definitions |
| 130 | 4 Symbols, subscripts and superscripts 4.1 General 4.2 Symbols |
| 132 | 4.3 Subscripts |
| 133 | 4.4 Superscripts 5 Characteristics of short-circuit currents: calculating method 5.1 General |
| 134 | Figures Figure 1 – Short-circuit current of a far-from-generator short circuit with constant AC component (schematic diagram) |
| 135 | Figure 2 – Short-circuit current of a near-to-generator short-circuit with decaying AC component (schematic diagram) |
| 136 | 5.2 Calculation assumptions Figure 3 – Characterization of short-circuits and their currents |
| 137 | 5.3 Method of calculation 5.3.1 Equivalent voltage source at the short-circuit location |
| 138 | Figure 4 – Illustration for calculating the initial symmetrical short-circuit current in compliance with the procedure for the equivalent voltage source |
| 139 | 5.3.2 Symmetrical components Tables Table 1 – Voltage factor c |
| 140 | 6 Short-circuit impedances of electrical equipment 6.1 General 6.2 Network feeders |
| 141 | Figure 5 – System diagram and equivalent circuit diagram for network feeders |
| 142 | 6.3 Transformers 6.3.1 Two-winding transformers 6.3.2 Three-winding transformers |
| 144 | 6.3.3 Impedance correction factors for two- and three-winding network transformers Figure 6 – Three-winding transformer (example) |
| 145 | 6.4 Overhead lines and cables |
| 146 | 6.5 Short-circuit current-limiting reactors 6.6 Synchronous machines 6.6.1 Synchronous generators |
| 148 | 6.6.2 Synchronous compensators and motors 6.7 Power station units 6.7.1 Power station units with on-load tap-changer |
| 149 | 6.7.2 Power station units without on-load tap-changer |
| 150 | 6.8 Wind power station units 6.8.1 General 6.8.2 Wind power station units with asynchronous generator |
| 151 | 6.8.3 Wind power station units with doubly fed asynchronous generator |
| 152 | 6.9 Power station units with full size converter 6.10 Asynchronous motors |
| 153 | 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 |
| 154 | Table 2 – Importance of short-circuit currents |
| 155 | Figure 7 – 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 |
| 157 | Figure 8 – Examples of single-fed short-circuits Figure 9 – Example of a multiple single-fed short circuit |
| 158 | 7.1.2 Maximum and minimum short-circuit currents Figure 10 – Example of multiple-fed short circuit |
| 159 | 7.1.3 Contribution of asynchronous motors to the short-circuit current |
| 160 | 7.2 Three-phase initial short-circuit current 7.2.1 General |
| 161 | 7.2.2 Short-circuit currents inside a power station unit with on-load tap-changer |
| 162 | Figure 11 – 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 |
| 163 | 7.2.3 Short-circuit currents inside a power station unit without on-load tap-changer |
| 164 | 7.3 Line-to-line short circuit 7.4 Line-to-line short circuit with earth connection |
| 166 | 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 |
| 167 | Figure 12 – Factor κ for series circuit as a function of ratio R/X or X/R |
| 168 | 8.1.2 Multiple-fed short circuit |
| 169 | 8.2 Line-to-line short circuit 8.3 Line-to-line short circuit with earth connection 8.4 Line-to-earth short circuit |
| 170 | 9 Calculation of symmetrical breaking current 9.1 Three-phase short circuit 9.1.1 Symmetrical breaking current of synchronous machines |
| 171 | 9.1.2 Symmetrical breaking current of asynchronous machines Figure 13 – Factor μ for calculation of short-circuit breaking current Ib |
| 172 | 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 – Factor q for the calculation of the symmetrical short-circuit breaking current of asynchronous motors |
| 173 | 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 |
| 174 | 9.2 Unbalanced short-circuits 10 DC component of the short-circuit current |
| 175 | 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 |
| 177 | Figure 15 – Factors λmin and λmax factors for cylindrical rotor generators Figure 16 – Factors λmin and λmax for salient-pole generators |
| 178 | 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 |
| 179 | 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 |
| 180 | Figure 17 – Transformer secondary short-circuits, if one line (fuse) is opened on the high-voltage side of a transformer Dyn5 |
| 181 | 13 Terminal short circuit of asynchronous motors Table 3 – Factors α and β for the calculation of short-circuit currents with Formula (96), rated transformation ratio tr = UrTHV/UrTLV |
| 182 | 14 Joule integral and thermal equivalent short-circuit current Table 4 – Calculation of short-circuit currents of asynchronous motors in the case of a short circuit at the terminals |
| 183 | Figure 18 – 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) |
| 184 | Figure 19 – 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) |
| 185 | Annex A (normative) Formulas for the calculation of the factors m and n |
| 186 | Annex B (informative) Nodal admittance and nodal impedance matrices |
| 187 | Figure B.1 – Formulation of the nodal admittance matrix |
| 188 | Figure B.2 – Example Table B.1 – Impedances of electrical equipment referred to the 110 kV side |
| 190 | Bibliography |
