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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You can fault a single bus or all buses in the single-line diagram to view the short-circuit currents at the faulted buses. Impedances 2, between the starpoint of transformers and earth are to be introduced as 3 2, into eic zero-sequence system without a correction factor.

The impedances in systems connected through transformers to the system, in which the short circuit occurs, have 609099 be transferred by the square of the rated transformation ratio.

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Figure 1 gives schematically the general course of the short-circuit current in the case of a far-fiom- generator short circuit. Medium-voltage motors have to be considered in the calculation of maximum short-circuit current see 2.

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Then they contribute only to the initial symmetrical short-circuit current I: For unbalanced faults, equations 868788 and 89 ie used. I 1 unacceptable, marketing specialist other Electric and magnetic circuits IEC 15 1: For higher temperatures than 20 OC, see equation 3.

Synchronous Generator Impedance Correction Factor The synchronous iwc impedance correction factor K G for generators without unit transformers is calculated as follows per section 3. Peak current based on method c: For breaking current you can choose from 0.

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IEC-60909 Short-Circuit in EasyPower

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 For phase currents, the maximum isc of the three phases is used. The following values for the fictitious resistances RGfmay be used for the calculation of the peak short- circuit current with sufficient accuracy.

The impedances of the equipment in superimposed or subordinated networks are to be divided or multiplied by the square of the rated transformation ratio t. As a result, reversible static converter-fed drives are treated for the calculation of short-circuit currents in a similar way as asynchronous motors.

IEC Short-Circuit in EasyPower

When a number of short circuits occur with a short time interval in between them, the resulting Joule integral is the sum of the Joule integrals of the individual 6090 currents, as given in equation 1 Switches use the peak current to compare with making capacity.

The EasyPower library is populated with data for circuit breakers, fuses and switches.

In all cases I L is equal to Ikv,because the short circuits are far-from-generator short circuits see 1. Read an Excerpt Excerpt 1: You can also view the remote branch currents and remote bus voltages. The effect of series capacitors can be neglected in the calculation of short-circuit currents, if they are equipped with voltage-limiting devices in parallel, acting idc a short circuit occurs.

Radial Network Also, all synchronous machines use the resistance R Gf in place of R G in accordance with section 3. Calculation of a Generator 8. Fuses and low voltage circuit breakers ratings are compared with initial currents.


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

By understanding the theory any software allows users to perform all the 609009 calculations with ease so they can work on the design and application of low- and high-voltage power systems. The peak short-circuit current i, at a short-circuit location F, fed from sources which are not meshed with one another, in 609009 with figure 12, is the sum of the partial short-circuit currents: In the case of a near-to-generator short circuit, the short-circuit current can be considered as the sum of the following two components: Additional information may be found in 69009 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.

This occurs in the case of a far-from-generator short circuit. CE1 TR–I read: Calcul des courants Short-circuit currents in three-phase a. In this case, it is necessary to distinguish between networks with and without parallel branches see 4. The short-circuit impedances for electrical equipment are modified using impedance corrections factors that are calculated based on section 3.

This is the oec active voltage of the network 1.