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 manufacturer premises before delivering the transformer.
Mainly two types of transformer testing are done at manufacturer premises- type test of
transformer and routine test of transformer.
In addition to that, some transformer tests are also carried out at the consumer site
before commissioning and also periodically on a regular & emergency basis throughout
its service life.
In this video, we will learn the type of transformer testing in the manufacturing commissioning
and installation period and their procedure.
Type of Transformer Testing.
There are three types of transformer Tests done at the factory.
1.
Type tests.
2.
Routine tests.
3.
Special tests.
Type Test of Transformer.
To prove that the transformer meets the customer’s specifications and design expectations, the
transformer has to go through different testing procedures on manufacturer 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 the transformer confirms the main and basic design criteria of a production
lot.
Type tests of the transformer included.
1.
Transformer winding resistance measurement.
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.
Temperature rise test of transformer.
9.
Tests on on-load tap-changer.
10.
Vacuum tests on tank and radiators.
Routine Tests of Transformer.
Routine tests of the transformer are mainly for confirming the operational performance
of the individual units in a production lot.
Routine tests are carried out on every unit manufactured.
Routine tests of the transformer included.
1.
Transformer winding resistance measurement.
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 the transformer to check against leakages past joints and gaskets
is included.
Special Tests of Transformer.
Special tests of the transformer are done as per customer requirement to obtain information
useful to the user during the operation or maintenance of the transformer.
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.
We will be published continue transformer tests and their procedure one by one in the
next video.
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