IEC Power transformers – Part 4: Guide to the lightning impulse and switching impulse testing – Power transformers and reactors. Edition Guide to the lightning impulse and switching impulse testing –. Power transformers and reactors. Reference number. IEC (E). INTERNATIONAL. Buy IEC Ed. Power transformers Part 4: Guide to the lightning impulse and switching impulse testing – Power transformers and reactors from SAI.
|Country:||United Arab Emirates|
|Published (Last):||4 January 2008|
|PDF File Size:||9.95 Mb|
|ePub File Size:||16.14 Mb|
|Price:||Free* [*Free Regsitration Required]|
Standard Number BS This, in fact, represents a guideline for the arrangement of the chopping circuit and may entail the introduction of additional impedance Z c in this circuit to meet the limit see figure 1.
A significant increase, combined with a change in superimposed frequency in 60076–4 neutral current is indicative of a fault within the tested winding whilst a decrease indicates a fault from the tested winding to an adjacent winding or to earth.
Please download Chrome or Firefox or view our browser tips. Q2 Please tell us in what capacity ies you bought the standard tick all that apply.
The flux in these reactors cannot be directed through the windings on the non-tested limbs. A progressive but nevertheless total flashover across the winding under test will result in a somewhat slower voltage collapse, normally occurring in a stepped manner see figure B.
For transformers, any part-winding defect turn-to-turn failure, disc-to-disc breakdown, or breakdowns in tapping windings will result in a flux blockage and will easily be detected by voltage and current records. The intention of illustrating particular faults is to give general guidance only.
Any turn-to-turn or part winding fault will also produce an instantaneous current peak, but with a much more rapid voltage collapse, indicating a flux blockage. When switching impulses are performed from the low-voltage side of the transformer, only T 1 can be established from reduced voltage applications. Ability to withstand short-circuit Part 8: The scaling of each axis that is, magnitude and time should be shown on every oscillogram or digital recording.
Information is given on waveshapes, test circuits including test connections, earthing practices, failure detection methods, test procedures, measuring techniques and interpretation of results.
If no delta windings are available, only 1,0 p. Therefore, the virtual time to half-value is not used to specify the wavetail of the applied switching impulse. Consolidated editions The IEC is now publishing consolidated versions of its publications.
Such high opposite polarity oscillation may overstress inter-turn and inter-winding insulation due to high oscillatory stresses which can trigger partial discharges and enhanced electrode mechanisms only due to testing limitations. Q5 This standard meets my needs: In this case, T d and T z can only be determined from full test-level shots. Digitizers have been used in impulse testing since the s. Any changes in the frequency of the voltage and current recordings after the chopping should be investigated.
With this limitation, guidance for selecting impulse generator capacitance and adjusting waveshapes is given in annex A.
Learn more about the cookies we use ieec how to change your settings.
More details in 600764 respect are given in 7. Because the chopped wave contains more high-frequency input for the admittance transfer function, deviations between the RFW and FCW transfer functions only occur at high frequencies.
This test configuration is very suitable for current measurements since there is no increase in the circuit resistance and the circuit therefore has good response to high-frequency disturbances.
The sensitivity of this measurement is higher than that of the applied voltage. This configuration does not produce a sustained stress from winding to earth, but it does stress the insulation within the iecc.
Guide to the lightning impulse and switching impulse testing — Power transformers and reactors irc Scope This part of IEC gives guidance and explanatory comments on the existing procedures for lightning and switching impulse testing of power transformers to supplement the requirements of IEC This configuration tends to change turn-to-turn and coil-to-coil stresses, the amount of change depending on the winding time constants.
This problem may be solved to some extent by the 6007-4 of large capacitance within the generator, by parallel stage operation, by adjustment of the series resistor or by 6007-4 test connections of the terminals of windings not under test or, in addition, of the non-tested terminals of windings under test.
The presentation of the recordings for the acceptance test are the same as for the presentation of oscillograms in 7.
Similar considerations with 60067-4 to superimposed oscillations are valid also for singlephase auto-transformers. Information on the subjects under consideration and work in 6007-4 undertaken by the technical committee which has prepared this publication, as well as the list of publications issued, is also available from the following: With the application of digital recorders in highvoltage testing of power transformers, a warning with respect to amplitude and time parameters should be given with respect to the evaluation of non-standard waveshapes.
Therefore, the two items of equipment are dealt with separately. August Replaced By: Information relating to this publication, including its validity, is available in the IEC Catalogue of publications see below in addition to new editions, amendments and corrigenda.