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Test Guide for Cast Resin Dry Type Transformer - TRIHAL
Test Guide for Cast Resin Dry Type Transformer – TRIHAL

Measurement of no load losses and no load current

Test objective

  • Characterising the no load losses and the no load current of the transformer
  • Checking that the characteristics are in conformity with the current standard

In real terms, no load losses are generated by the area marked within the dotted line below :

Measurement of no load losses and no load current scheme
Measurement of no load losses and no load current scheme

Test procedure

The low voltage (LV) winding is supplied with the rated voltage at the rated frequency, with the medium voltage (MV) winding open-circuited.

A three-phase precision wattmeter is used for measurements and gives directly :

  • the applied voltage (true r.m.s.)
  • the 3 currents (true r.m.s.)
  • the average current
  • the no load losses

NOTE: the values measured on transformers with several LV windings are obtained on the winding with the highest voltage, in other words the one offering the best accuracy.


Test rig diagram

Voltmeters and ammeters integrated on the test rig enable the values to which the transformer is subjected to be measured at any point in time.

Test rig diagram
Test rig diagram

Tolerances

The application of small tolerances on the no load losses is negotiable at the time of the request for tender.

Title:Test Guide for Cast Resin Dry Type Transformer ‘TRIHAL’ – Schneider Electric
Format:PDF
Size:2.4 MB
Pages:45
Download:Right here | Get Download Updates | Get Technical articles
Test Guide for Cast Resin Dry Type Transformer TRIHAL
Test Guide for Cast Resin Dry Type Transformer TRIHAL

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Page edited by E.C. (Google).

4 Comments


  1. Mohammad Hosein
    May 11, 2014

    many thanks for such useful information I have transmission lines by sf6 gases .


  2. Kotoulas Thanasis
    Jan 23, 2014

    A customer made a measurement for windings resistance on a 20/0.4 kV 1000 kV trafo, with an microohm meter (μΩ). Do you thing is valid? Thank you, nice info everytime !


    • ayyagari
      Apr 14, 2014

      It is not correct to measure the winging resistance of higher capacity transformers with micro ohmmeter. Use winding resistance kit. If at all to use microohm meter, first connect only the current circuit leads and connect the voltage circuit leads after some seconds of time and allow the reading to settle for almost fixed reading.
      Ayyagari


  3. emad1
    Dec 11, 2012

    Many Thanks for such useful information
    Best Regards

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