IEC 60909-0 PDF
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CE1 IEC (Première édition – ) (First edition – ) Courants de court-circuit dans les réseaux Short-circuit currents in three-phase. IEC Edition INTERNATIONAL. STANDARD. NORME. INTERNATIONALE. Short-circuit currents in three-phase a.c. systems –. Buy IEC SHORT-CIRCUIT CURRENTS IN THREE-PHASE A.C. SYSTEMS – PART 0: CALCULATION OF CURRENTS from SAI Global.
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The zero-sequence short-circuit impedance at the short-circuit location F is obtained according to figure 5c, if an a. It is not necessary for the product 1, Calculate the Impedance 8. For the calculation of the partial short-circuit current I L 2 69009-0 into the short-circuit location F2, for example at the connection to the high-voltage side of the auxiliary transformer AT in figure 13, it is sufficient to take: Methods of Calculations 1 1.
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When calculating the partial short-circuit current I: The impedance correction factor shall be applied also to the negative-sequence and the zero- sequence impedance of the transformer when calculating unbalanced short-circuit currents. Connection Box to Service Panel If the highest partial short-circuit current of the power station unit at the high-voltage side of the unit transformer with off-load taps is searched for, choose l-pT.
They may be neglected. Proof of the Stability of Low-Voltage Systems T JSrT ; t, is the rated transformation ratio of the unit transformer: Factor p for calculation of short-circuit breaking current 1, When calculating unbalanced short-circuit currents in medium- or high-voltage systems and applying an equivalent voltage source at the short-circuit location, the zero-sequence capacitances of lines and the zero-sequence shunt admittances are to be considered for isolated.
O 1 marks the positive-sequence neutral reference. For undated references, the latest edition of the normative document referred to applies.
Permissions Request permission to reuse content from this site. In the case of a near-to-generator short circuit, the short-circuit current can 660909-0 considered as the sum of the following two components: International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation.
The initial short-circuit current at the short-circuit location F is the phasor sum of the individual partial short-circuit currents see figure Connection of a Motor The correction factor Kso shall also be applied to the zero-sequence system impedance of the power station unit excepting, if present, an impedance component between the star point of the transformer and earth. Impedances between a starpoint and earth shall be introduced without correction factor.
The total short-circuit in F1 or F2 figure 13 is found by adding the partial 609090- current ILrnv, caused by the medium- and low-voltage auxiliary motors of the power station unit.
I cochez tout ce qui convient Je suis lehn: Calcul des courants Part O: The impedance of the auxiliary transformer AT in figure 13 is to be corrected with KT from 3. 6090-0 effective resistance of the stator of synchronous machines lies generally much below the given values for RGf.
The results of the short-circuit current calculation have an acceptable accuracy also in the case of untransposed overhead lines. These values cannot be used when calculating the aperiodic component id.
In all cases I L is equal to Ikv,because the short circuits are far-from-generator short circuits see 1. If underexcited operation of the power station unit is expected at some time for instance to a large extent oec in pumped storage plantsthen only when calculating unbalanced short- circuit currents with earth connection see figures 3c and 3d the application of Ks according to equation 22 may lead to results at the non-conservative side. Ik Steady-state short-circuit current r.
CE1 TR–l read: Enter the exact the reason is: The generator impedance shall be transferred to the high-voltage side using the rated transformation ratio t. All other active voltages in the system are assumed to be zero.
Definitions,principles and rules IEC 1: In this case, the three-fold zero-sequence current flows through the joint return.
Short Circuits in Power Systems: A Practical Guide to IEC 60909-0, 2nd Edition
Xk may be neglected. At this kec, the publication will be 0 reconfirmed; 0 withdrawn; 0 replaced by a revised edition, or 0 amended. I 1 unacceptable, marketing specialist other Factor q for the calculation of the symmetrical short-circuit breaking current of asynchronous motors Example of a meshed network fed from several sources NOTE Equivalent circuits of the positive-sequence and the zero-sequence system are given in IECtable Iitem 4 to 7 for different cases of starpoint earthing.
Short-circuit currents and short-circuit impedances may also be determined by system tests, by measurement on a network analyzer, or with a ief computer. The effective resistance per unit length RL of overhead lines at the conductor temperature 20 “C may be calculated from the nominal cross-section qn and the resistivity p: For these equivalent asynchronous motors, including their connection cables, the following may be used: In some special cases, it could happen that the decaying short-circuit current reaches zero for the first time, some cycles after the short circuit took place.
All other static converters are disregarded for the short-circuit current calculation according to this standard. The calculation of the three-phase peak short-circuit current i, applies to the line conductor and to the instant at which the greatest possible short-circuit current exists.
Calculations are simplest for balanced short circuits on radial systems, as the individual contributions to a balanced short circuit can be evaluated separately for each source figures 12 or