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.
In this case the manufacturer’s values 60909–0 RG should be used. This part of IEC establishes a general, practicable and concise procedure leading to results, which are generally of acceptable accuracy.
Ik Steady-state short-circuit current r. Short-circuit current of a far-from-generator short circuit with constant a.
Short Circuits in Power Systems: A Practical Guide to IEC 60909-0, 2nd Edition
Radial Network I librarian researcher I design engineer safety engineer ci Q7 Please assess the standard in the I following categories, using testing engineer ci the numbers: This is possible if the d. Proof of the Stability of Low-Voltage Systems Figure 1 – Short-circuit current of a far-from-generator short circuit with constant a.
Transformers in Parallel In the calculation of short-circuit currents, those medium-voltage and low-voltage motors may be neglected, provided that, according to the circuit diagram interlocking or to the process reversible drivesthey are not switched in at the same time. If underexcited operation of the power station unit is expected at some time for instance to a large extent especially 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.
It is assumed that the operating voltage at the terminals of the generator is equal to UrG. When a number of short circuits occur with a short time interval in 69009-0 them, the resulting Joule integral is the sum of the Joule integrals of the individual short-circuit currents, as given in equation 1 Using this method, the currents in each line conductor are found by superposing the currents of the three symmetrical component systems: The values are given in table 1 NOTE The uec of a voltage factor c is necessary for various reasons.
Calcul des courants Short-circuit currents in three-phase 609099-0. The equations 46 and 47 are given for the calculation of and in figure 3c: Factor n for the heat effect of the a.
Normally, the steady-state short-circuit current Ik is smaller than the symmetrical short-circuit breaking current 1. Design and Calculation of aWind Farm 8.
Help Center Find new research papers in: At this date, the publication will be 0 reconfirmed; 0 withdrawn; 0 replaced by a revised edition, or 0 amended. With these impedances the corrected equivalent impedances LK, z B K and ZCKshall be calculated using the procedure given in equation i i. I 1 unacceptable, marketing specialist other This correction factor shall not be introduced for unit transformers of power station units see 3.
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For the calculation of the partial short-circuit current I L 2 feeding 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: In the case of high-voltage feeders with nominal voltages above 35 kV fed by overhead lines, the equivalent impedance 2, may in many cases be considered as a reactance, i. Meshed Network Examples f o r the calculation of short-circuit currentsi The committee has decided that the contents of this publication will remain unchanged until In all cases it is possible to determine the short-circuit current at the short-circuit location F with the help of an equivalent voltage source.
In meshed networks there are several direct-current time constants.
The IEC shall not be held responsible for identifying any or all such patent rights. For 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 600909-0 equations 7 to 9: In this case, the three-fold zero-sequence current flows through the joint return.
The values of p in equation 70 apply if synchronous machines are excited by rotating exciters or by static converter exciters provided, for static exciters, the minimum time delay tminis less than ic s and the maximum excitation voltage is less than 1,6 times rated load excitation-voltage. Figure 1 gives schematically the general course of the short-circuit current in the case of a far-fiom- generator short circuit.
In a near-to-generator short circuit, the short-circuit current behaves generally as shown in figure 2. It does not take into account adjustable time delays of tripping 609009-0. The factor n in figure 22 is given by: The impedance of the network feeder and the transformer are related to the LV-side and the last one is also corrected with KT see 3. Impedances between a starpoint and 609099-0 shall be introduced without correction factor.
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 if a short circuit occurs. The estimation according to equation 28 is not allowed in the case of three-winding ifc.
Request permission to reuse content from this site. Currents calculated with equation 74 are larger than the real symmetrical short-circuit breaking.
For simplification, it is permitted to use the same value for IC as for the three- phase short circuit. This procedure is not allowed when calculating the peak short-circuit current i.
For the calculation of the initial short-circuit currents according to 4. A contribution is also given if, in case of a power station unit, the short-circuit occurs on the high-voltage side of the unit transformer see figure 1lc.
If the long-term operating conditions of network transformers before the short circuit are known for sure, then the following equation 12b may be used instead of equation 12a.