ADR233B
Ref ID : ADR233B/IM/PS
Rev No. : 05
Page No. : 129 of 479
The ADR233B relay does the automatic phase compensation based on the reference of
transformer vector group parameter, entered into the relay software.
For example; the Transformer vector group DY1 can be set in ADR233B relay following way;
“W1 Connection” = D-Delta (example)
“Vector Group “= 1 (example)
“W2 Connection” = Y-wye (example)
Vector Group Phase Shift
Yy0 0°
Dd0 0°
Dz0 0°
Yd1 -30°
Dy1 -30
Yd5 -150°
Dy5 -150°
Yy6 180°
Dd6 180°
Dz6 180°
Yd11 +30°
Dy11 +30°
Transformer vector group number represents the phase shift between the current in a low
voltage winding with respect to its counterpart on the high voltage winding. This corresponds to
the position of the number of a standard clock face. The table1 below shows examples of
connections with the clock vectors Midnight, 1 o’ clock, 6 o’ clock and 11 o’clock, which is
equivalent to a phase shift of 0°, -30°, -180° and +30° respectively. The enough amount of
differential current generated due to the transformer phase difference and then it may lead to
undesirable tripping during normal operating condition.
The ADR233B relay does the automatic phase compensation based on the reference of
transformer vector group parameter, entered into the relay software.
Transformer Differential operating characteristics
ADR233B relay provides dual slope tripping characteristics in order to issue the differential trip
only for the winding internal fault
The differential tripping characteristic has two knees. The first knee is dependent on the settings
of Is>1 and Slope1. The second knee is defined by the setting Is>2 and slope2. The lower slope
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