You can enter equipment data and parameters via user friendly interface. The IEC standard terminology is used in the user interface and reports. EasyPower supports the following four types of short-circuit conditions as per IEC 3-phase short circuit Line-to-line short circuit with earth connection double line-to-earth Line-to-earth short circuit. Corresponding voltages can be displayed at the buses.
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Yogor If only overexcited operation is uec, then for the calculation of unbalanced short-circuit currents the correction factor Ks from equation 22 shall be used for both the positive-sequence and the negative-sequence system impedances of the power station unit. Request permission to reuse content from this site. Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work.
If the short circuit is a far-from-motor short circuit i. Any branch may be a series combination of several impedances. Figure 20 describes this situation with balanced and unbalanced short circuits with earth connection at the short-circuit location F. Short-circuit current of a far-from-generator short circuit with constant a. If the Joule integral or the thermal equivalent short-circuit current shall be calculated for unbalanced short circuits, replace I: Transformer secondary short circuits.
Impedances between a starpoint and earth shall be introduced without correction factor. Depending on the product f. For simplification, it is permitted to use the same value of Kas for the three-phase short circuit.
I cochez tout ce qui convient Je suis lehn: This part of IEC does not deal with the calculation of short-circuit currents in installations on board ships and aeroplanes.
The factor K shall, be calculated according to 4. As a result, reversible static converter-fed drives are treated for the calculation of short-circuit currents in a similar way as asynchronous motors. The zero-sequence short-circuit impedance at the short-circuit location F is obtained according to figure 5c, if an a. For grounded systems the influence of motors on the line-to-earth short-circuit current cannot be neglected.
You are currently using site but have requested a page in the site. The text of this standard is based on the following documents: The initial short-circuit current at the short-circuit location F is the phasor sum of the individual partial short-circuit currents see figure For the short-circuit impedances of synchronous generators in the negative-sequence system, the following applies with KG from equation 1 8: The capacitances of lines overhead lines and cables of low-voltage networks may be neglected in the positive- negative- and zero-sequence system.
Transformers in Parallel When an impedance is present between the starpoint of the generator and earth, the correction factor KG shall not be applied to this impedance. For balanced and unbalanced short circuits as shown in figure 3, it is useful to calculate the short-circuit currents by application of symmetrical components see 2.
NOTE For some near-to-generator short circuits the value of id. For the examples in figures 1Ib and 1 IC, the initial symmetrical short-circuit current is calculated with the corrected impedances of the generator and the power station unit see 3. For the short-circuit impedance of synchronous generators in the zero-sequence system, the following applies with KG from equation 1 8: Calculation of a Cable 8.
Table of contents Preface xi Acknowledgments xiii 1 Definitions: For currents during two separate simultaneous single-phase line-to-earth short circuits in an isolated neutral system or a resonance earthed neutral system, see IEC IkP Steady-state short-circuit current ie the terminals poles of a generator with compound excitation Initial symmetrical short-circuit current r.
For simplification, it is permitted to the same value for as for the three- phase short circuit. The values of positive-sequence and negative-sequence impedances can differ from each other only in the of rotating machines. For simplification of the calculation, groups of motors including their connection cables may be combined to a single equivalent motor see motor M4 —0 figure 9. This procedure is not allowed when calculating the peak short-circuit current i.
This fault is beyond the scope of, and is therefore not dealt with in, this standard. The decaying aperiodic component An example for the introduction of the correction factors of equation 13 to the positive-sequence and the zero-sequence system impedances of the equivalent circuits is given in 2. Special methods to calculate i, with sufficient accuracy are given in 4. Calcul des courants Part O: Would you like to change to the site? Normally, the steady-state short-circuit current Ik is smaller than the symmetrical short-circuit breaking current 1.
For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. Related Posts
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