Telephone: +41 22 02 11 Telefax: +41 22 03 00 E-mail: [email protected] Web: INTERNATIONAL. STANDARD. IEC. Third edition. This part of IEC identifies the requirements for power transformers to sustain without damage the effects of overcurrents originated by external short. IEC. Second edition. This English-language version is As from 1 January all IEC publications are issued with a designation in the.
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Application guide IEC If this is not the case, a single-phase supply, as described below, may be used. Safety of power transformers, power suply units and similar Part 2: There may be also a certain change of reactance with time after the tests. Ability to withstand short circuit YEAR. The IEC shall not be held responsible for identifying any or all such patent rights.
INTERNATIONAL STANDARD IEC 60076-5
The manufacturer and the purchaser should agree which kind of short circuit is to be considered. Particular requirements for separating transformers for general use.
Table of physical and chemical constants — Kay and Laby — 15 edition, Longmans, In order to consider the transformer as having passed the short-circuit tests, the following conditions shall be fulfilled: This applies, for example, to unit generator transformers if the connection between generator and transformer is constructed in such a way that the possibility of line-to-line or ief faults in this region is negligible. Enter the exact number of the standard: In this context, a check of the axial compression of 60076-55 windings could be useful.
In this case, a more detailed examination may be required, including a dismantling of the unit as necessary to lec the cause of the deviation.
Unless otherwise specified, the three tests on a single-phase transformer iiec tappings are made in a different position of the tap-changer, i. The results of the short-circuit reactance measurements and the oscillograms taken during the different stages of the tests shall be examined for any indication of possible anomalies during the tests, especially any indications of change in the short-circuit reactance.
This increase in current should be taken into consideration when calculating the temperature rise of the zigzag winding.
INTERNATIONAL STANDARD IEC
When calculation and design consideration is selected, validation 600766-5 comparison with a previously tested similar transformer or tests on representative models is required.
IEC Power transformers Part 5: NOTE 3 If, for star-connected windings, the power supply is insufficient for the single-phase testing described above and the neutral is available, the manufacturer and the purchaser may agree upon the use of single-phase power supply between line terminal and the neutral, provided that neutral is capable of carrying the relevant current.
All International European Italian Selector: These characteristics shall be specified by the purchaser in his enquiry. Particular requirements for isolating transformers for the supply of medical locations IEC 660076-5 of power transformers, power supplies, reactors and similar products Part To make sure that we continue to meet your needs, your feedback is essential. U is, unless otherwise specified, the tapping voltage 2 of isc winding under consideration, in kilovolts; Z t is the short-circuit impedance of the transformer referred to the winding and the tapping under consideration, in ohms per phase.
Ability to withstand short circuit This English-language version is derived from the original bilingual publication by leaving out all French-language pages. This time shall be defined by agreement between the manufacturer and the purchaser. Please assess the standard in the following categories, using the numbers: If the short-circuit apparent power of the 6006-5 is not specified, the values given in table iev shall be used.
Reference 60706-5 IEC Particular requirements and tests for auto transformers and power supply units incorporating auto transformers. The characteristics of each system at least the short-circuit apparent power level and the range of the ratio between zero-sequence impedance and positive-sequence impedance shall be specified by the purchaser in his enquiry.
In general, such conditions are of a more complex nature in comparison with the three-phase short circuit which can be considered the reference case for two-winding transformers see 3. NOTE 2 When insulation systems other than thermal class A are employed in oil-immersed transformers, different maximum values of temperature may be allowed by agreement between the manufacturer and the purchaser.
CombiFinder Discover how to find in thousands configurations, the Combination unit for you. The text of this standard is based on the following documents: NOTE 2 Generally, the short-circuit reactance variation should show a tendency to diminish in the course of the tests.
Information on the subjects under consideration and work in progress undertaken by the technical committee which has prepared this publication, as well as the list 60076-55 publications issued, is also available from the following: In this case, provision should be made by the purchaser to limit the overcurrent to the maximum value determined by the manufacturer and stated on the rating plate. The requirements apply to transformers as defined in the scope of IEC Hence, if there is a high variation of reactance exceeding the prescribed 600776-5, based on measurements made immediately after the test, it may be prudent to repeat the measurements after an interval in order to check whether the variation is maintained.
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If lower values are required, the ability of the transformer to withstand short circuit shall be subject to agreement between the manufacturer and the purchaser. Safety of power transformers, power supplies, reactors and similar products Part NOTE 3 Temporary sparks over tank joints may occur at the energizing stage and internal sparking at the frame joints at the energizing and short-circuit stages. This last value of reactance is accepted as the final value when determining compliance with the requirements of the standard.