This calculation is based on IEC (, c), “Short-circuit currents in three-phase a.c. systems – Part 0: Calculation of currents” and. EasyPower offers a complete and accurate solution to short-circuit calculations in three-phase AC systems using the IEC standard. You can enter. IEC Edition INTERNATIONAL. STANDARD. NORME. INTERNATIONALE. Short-circuit currents in three-phase a.c. systems –.

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Earthing and protection against electric shock IEC The object of the IEC is to promote 60099 co-operation on all questions concerning standardization in the electrical and electronic fields.

EasyPower supports the following four types of short-circuit conditions as per IEC For rotating machines the current contributions to short-circuit decays over time. NOTE For some near-to-generator short circuits the value of id. CE1 TR–I read: Special methods to calculate i, with sufficient accuracy are given in 4.

Corresponding voltages can be displayed at the buses. Short-circuit impedances of a three-phase a. For transformers with delta and start wye winding connections, the clock notations 1,3,5,7,9 and 11 609909 supported in the database.

## IEC-60909 Short-Circuit in EasyPower

Transformers in Parallel This is lec 3I0 value 3 times the zero sequence current. I education ci military ci I other Method c is recommended in meshed networks see IEC The values are given in table 1 NOTE The introduction of a voltage factor c is necessary for various reasons. Any branch may be a series combination of several impedances. Regardless of the time of short-circuit occurrence, the discharge current of the shunt capacitors may be neglected for the calculation of the peak short-circuit current.

Synchronous machines generators, motors, or compensators with terminal-fed static exciters do ice contribute to I k in the case of a short-circuit at the terminals of the machine, but they contribute to l k if there is an impedance between the terminals and the short-circuit location. EasyPower provides 69009 necessary phase angle shift of remote voltages and currents for IEC rated transformers in the IEC short circuit analysis.

## Short Circuits in Power Systems: A Practical Guide to IEC 60909-0, 2nd Edition

This method applies the 1. Calcul des courants Short-circuit ie in three-phase a. IEC TR2- lire: Short-circuit current-limiting reactors shall be treated as a part of the short-circuit impedance.

If the short circuit is a far-from-motor short circuit i. Calculate the Impedance 8.

As long as RIX remains smaller than 0,3 in all branches, it is not necessary to use the factor 1, This book is a practitioner’s guide intended for students, electrical engineers, engineers in power technology, the electrotechnical industry, engineering consultants, energy suppliers, chemical engineers and physicists in industry. Supply to a Factory The following values for the fictitious resistances RGfmay be used for eic calculation of the peak short- circuit current with sufficient accuracy.

Request permission to reuse content from this site. For simplification, it is permitted to use the same value for as for the three- phase short circuit.

Calculation of an LV motor 8. I tables, charts, graphs, figures Peak current based on method b: Phasor diagram of a synchronous generator at rated conditions In some special cases, it could happen that the decaying short-circuit current reaches iecc for the first time, some cycles after the ief circuit took place. No short-circuit current on the low-voltage or on the high-voltage side of the transformer in figure 20 is higher than the highest balanced or unbalanced short-circuit current in the case of an intact HV-feeding see figure For unbalanced faults, equations 868788 and 89 are used.

Calculation for an Industrial System I is not at all ci Figure 2 – Short-circuit current of a near-to-generator short circuit with decaying a. The correction factor Ks 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.

Z THV is the impedance of the unit transformer referred to the high-voltage side without correct factor K T.

It does not take into account adjustable time delays of tripping devices. Ic two-winding transformers with and without on-load tap-changer, an impedance correction factor KT is to be introduced in addition to the impedance evaluated according to equations 7 to 9: The following methods are supported for meshed networks as per section 4.

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For minimum short-circuit currents, the resistances are based on the estimated temperature at the end of the short-circuit condition. These have, 90, and 30 degrees phase shift respectively based on the high voltage side taken as the reference.

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 As described in the methodology the solution is obtained using the equivalent voltage source at the short-circuit location, symmetrical components impedance network, and the voltage factor c.

Factor q for the calculation of the symmetrical short-circuit breaking current of asynchronous motors