Power Transformer Routine Test
There is various Test required on Transformer to confirm the performance of the Transformer.
Two types of transformer are done by the manufacturer before dispatching the transformer mainly:-
1- Type test of transformer
2- Routine test.
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Transformer Testing mainly classified in
Transformer Tests are done by Manufacturer
(A) Routine Tests
(B)Type Tests
(C) Special Tests
Transformer Tests were done at Site
(D) Pre Commissioning Tests
(E) Periodic/Condition Monitoring Tests
(F) Emergency Tests
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A Routine test of the transformer is mainly for confirming the operational performance of an individual unit in a production lot. Routine tests are carried out on every unit manufactured.
All transformers are subjected to the following Routine tests:
1-Insulation resistance Test.
2-Winding resistance Test.
3-Turns Ration / Voltage ratio Test
4-Polarity / Vector group Test.
5-No-load losses and current Tests.
6-Short-circuit impedance and load loss Test.
7-Continuity Test
8-Magnetizing Current Test
9-Magnetic Balance Test
10- High Voltage Test.
11-Dielectric tests
12-Separate source AC voltage.
13-Induced overvoltage.
13- Lightning impulse tests.
15- Test on On-load tap changers, where appropriate.
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Type tests are tests made on a transformer which is representative of other transformers to demonstrate that they comply with specified requirements not covered by routine tests:
1-Temperature rise test (IEC 60076-2).
2- Dielectric type tests (IEC 60076-3).
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Special tests are tests, other than routine or type tests, agreed between manufacturer and purchaser.
1-Dielectric special tests.
2-Zero-sequence impedance on three-phase transformers.
3-Short-circuit test.
4-Harmonics on the no-load current.
5-Power taken by a fan and oil-pump motors.
6-Determination of sound levels.
7-Determination of capacitances between windings and earth, and between windings.
8-Determination of transient voltage transfer between windings.
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The Test performed before commissioning the transformer at the site is called the pre-commissioning test of the transformer. These tests are done to assess the condition of the transformer after installation and compare the test results of all the low voltage tests with the factory test reports.
All transformers are subjected to the following Pre-commissioning tests:
1-IR value of transformer and cables
2-Winding Resistance
3-Transformer Turns Ratio
4-Polarity Test
5-Magnetizing Current
6-Vector Group
7-Magnetic Balance
8-Bushing & Winding Tan Delta (HV )
9-Protective relay testing
10-Transformer oil testing
11-Hipot test
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