Three Phase Banks - NDB Technologies NDB-DOC-3 User Manual

7.3 Three Phase Banks

When we are working with 3 phase banks that are built using 3 single phase trans-
former (pole mount type). On these single phase transformers you will see name
plates that shows something like H.V. = 4160GNDY / 2400 V as shown below.
Basically this tells you that the
transformer can be used in a 3
phase, grounded, Wye (Yn) con-
figuration where the Line-Line
(system Voltage) would be 4160V.
But if you where to use this same
single phase transformer in a
Delta bank configuration then it
would be used on a 2400V system.
Using the NDB-DOC-3 with transformer banks we use the primary system voltages.
Using the name plate in the picture above:
• In a delta bank configuration example above, we would enter: 2kV and 225kVA
(3 x 75kVA). Our test leads would connect to the de-energised bushings of the
transformer bank: H1 test lead to H1 bushing of the of first transformer, H2 test
lead to H1 bushing of the 2nd transformer and H3 test lead to the H1 bushing
of the 3rd transformer.
• In a wye with neutral bank configuration, we would enter: 2kV and 225kVA (3
x 75kVA). Our test leads would connect to the de-energised bushings of the
transformer bank: H1 test lead to H1 bushing of the of first transformer, H2 test
lead to H1 bushing of the 2nd transformer and H3 test lead to the H1 bushing of
the 3rd transformer and lastly the H0 test lead to the neutral/ground bushing.
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