Transformer Testing Type Test and Routine Test of Transformer
Transformer Testing Type Test and Routine Test of Transformer
Transformer Testing Type Test and Routine Test of Transformer
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.
AN BN CN
Voltage applied at left side phase 230 V 180 V 50 V
1. First of all keep the tap changer in the lowest position and
open all IV and LV terminals.
2. Then apply three phase 415 V supply on the line terminals for
three phase transformers and single phase 230 V supply on
single phase transformers.
3. Measure the supply voltage and current in each phase.
4. Now repeat the magnetizing current test of transformer test
with keeping tap changer in normal position.
5. And repeat the test with keeping the tap at highest position.
Generally there are two similar higher readings on two outer limb
phases on transformer core and one lower reading on the centre
limb phase, in case of three phase transformers. An agreement to
within 30% of the measured exciting current with the previous test
is usually considered satisfactory. If the measured exciting current
value is 50 times higher than the value measured during factory
test, there is likelihood of a fault in the winding which needs further
analysis.
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