Buy IEC/TR Ed. Short-circuit currents in three-phase a.c. systems Part 4: Examples for the calculation of short-circuit currents from SAI Global. The results meet requirements of IEC and match the example provided in IEC TR section 6. The IEC standard terminology is used in the user. The International Electrotechnical Commission (IEC) is the leading global IEC TR , Short-circuit currents in three-phase a.c. systems – Part 4.

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Capacitors and non-rotating loads are not included in the calculations.

Transformers having different winding configurations, such as a delta connection on one side and a star wye connection on the other side, have a designated shift in the phase angles of currents and voltages. You can also view the remote branch currents and remote bus voltages. The short-circuit impedances for the examples in figures 1l b and 1I C are given by the following equations: RL is the line resistance for a conductor temperature of 20 OC, when calculating the maximum short-circuit currents.

The short circuit rating is part of the data library.

Calcul des courants Part O: The following methods are supported for meshed networks as per section ief. Factor m for the heat effect of the d.

IEC TR 60909-4:2000

You can display short-circuit tick marks for initial, breaking and steady state currents. The implementation is as per sections 4. For simplification, it is permitted to use the same value 6090-94 as for the three- phase short circuit. Method c is recommended in meshed networks see IEC Three-phase short-circuit currents for breaking I b at0.

Display of short-circuit currents You can view the 6009-4 in various formats such as phase currents for A, B and C phases or in symmetrical components: IEC- lire: Peak current based on method b: Motor contributions are excluded. When an impedance is present between the starpoint of the generator and earth, the correction factor KG shall not be applied to this impedance. Line-to-earth short-circuit currents for Initial symmetrical rms and peak Short-Circuit Duty Calculations EasyPower compares the short circuit results with protective device short-circuit ratings and displays the results in the text report and in the single line diagram.

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You can obtain the following values of short-circuit currents at the fault location for both maximum and minimum short circuit currents:. Rated voltage, line-to-line r.

IEC-60909 Short-Circuit in EasyPower

I education ci military ci I other 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. In all cases it is possible to determine irc short-circuit current at the short-circuit location F with the help of an equivalent voltage source. Highlighting of buses when voltage is below threshold Figure 7: DC component of short-circuit current at breaking times: Currents during two separate simultaneous single-phase line-to-earth short circuits and partial short-circuit currents following 6909-4 earth IEC TR Nominal system voltage, line-to-line r.

The zero-sequence system impedance Z,, of the motor shall be given by the manufacturer, if needed see 4. However, iwc to agreements based on this part of IEC are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.

I cochez tout ce qui convient Je suis lehn: This fault is beyond the scope of, and is therefore not dealt with in, this standard. It is assumed that the operating voltage at the terminals of the generator is equal to UrG.

Figure 16 can be used also for compound excited low-voltage generators with a minimum time delay tminnot greater than 0,1 s.

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In the case of high-voltage direct-current transmission systems, the capacitor banks and filters need special considerations, when calculating a.

Xk may be neglected. With respect to equation 99 in table 3 the steady-state short-circuit current of iev motors is zero in the case of a three-phase short circuit at the terminals figure 12 and equation The three impedance correction factors given in equation 13 shall be introduced also to the negative-sequence and to the zero-sequence systems of the three-winding transformer.

In this case the Joule integral is determined from the characteristic of the current-limiting device. The calculation of the minimum steady-state short-circuit current in the case of a near-to- generator short circuit, fed 60990-4 one or’ several similar and parallel working generators with compound excitation, is made as follows: The impedance of the auxiliary transformer AT in figure 13 is to be corrected with KT from 3.

If synchronous motors have a voltage regulation, they are treated like synchronous generators. I certification technical documentation ci ci For unbalanced faults, equations 868788 and 89 are used. Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work.

IEC TR | IEC Webstore

Remember me on this computer. In this case the manufacturer’s values for RG should be used. Within the accuracy of this standard, it is often sufficient to determine the short-circuit current at iecc short-circuit location F as being the sum of the absolute values of the individual partial short- circuit currents.