Transformer Testing at ECS

For confirming the specifications and performances of an electrical power transformer it has to go through a number of testing procedures. Some tests are done at a transformer manufacturer premises before delivering the transformer.Transformer manufacturers perform two main types of transformer testingtype test of transformer and routine test of transformer.

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TEST BENCH SUBSTATION AREA
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TEST BENCH
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TRANSFORMER WORKSHOP
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TEST BENCH SUBSTATION AREA

There are also tests done at site:

  1. Pre-commissioning tests
  2. Periodic/condition monitoring tests
  3. Emergency tests

TYPES TEST OF TRANSFORMER

To prove that the transformer meets customer’s specifications and design expectations, the transformer has to go through different testing procedures in ESC premises. Some transformer tests are carried out for confirming the basic design expectation of that transformer. These tests are done mainly in a prototype unit not in all manufactured units in a lot. Type test of transformer confirms main and basic design criteria of a production lot.

At ECS, we focus on the routine tests of transformer which  include

  1. Winding resistance test of transformer
  2. Transformer ratio test
  3. Transformer vector group test
  4. Measurement of impedance voltage/short circuit impedance (principal tap) and load loss (Short circuit test)
  5. Measurement of no load loss and current (Open circuit test)
  6. Measurement of insulation resistance
  7. Dielectric tests of transformer.
  8. Tests on on-load tap-changer.
  9. Oil pressure test on transformer to check against leakages past joints and gaskets

That means Routine tests of transformer include all the type tests except temperature rise and vacuum tests. The oil pressure test on transformer to check against leakages past joints and gaskets is included.

Special Tests of transformer include

  1. Dielectric tests.
  2. Measurement of zero-sequence impedance of three-phase transformers
  3. Short-circuit test
  4. Measurement of acoustic noise level
  5. Measurement of the harmonics of the no-load current.
  6. Measurement of the power taken by the fans and oil pumps.
  7. Tests on bought out components / accessories such as buchhloz relay, temperature indicators, pressure relief devices, oil preservation system etc.