ADR233B
Ref ID : ADR233B/IM/PS
Rev No. : 05
Page No. : 131 of 479
High set Functions
There are two additional settings for the high internal fault in winding of the transformer (IHs>1
and IHs>2)
If the differential current is above the adjustable IHs>1 setting threshold, the device will asserted
trip if the differential current in the operate region. However, harmonic blocking is not taken into
account. The IHs>1 resets when the differential and bias currents are in the restraint area.
If the differential current is above the adjustable IHs>2 setting threshold, bias current is not
taken into account and the device will trip regardless. As with IHs>1, harmonic blocking is not
taken into account. The IHs>2 element resets when the differential current drops below 0.95*
IHs>2.
Harmonic Blocking Criteria:
The ADR233B relay provides harmonic blocking or restrain based on the selection of Hrm Blk
Criteria setting as Blocking/Restrain.
Harmonic Restrain Selection:
Ih2
X 2H diff Threshold
Ih4
X 4H diff Threshold
+
-
IRT
(Slo pe1, Slo pe2)
Iop
87T
Figure 7: Harmonic Restrain characteristics
Slope characteristics are shifting automatically to enable correct phase differential trip as shown
in the above logic diagram. Then the slopes are shifting accordingly after that the operating
principle is same as phase differential slope.
For this criterion, Cross blocking is not considered.
Harmonic Blocking selection
ADR233B has the features of Harmonic blocking where user can select the mode of blocking
using the Hrm Blk mode .which can be select as second harmonic as 2H or second harmonic
and 4
th
harmonic mode as 2H&4H.
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