ABB REL 551 2.3 Series Installation And Comissioning Manual page 107

Line differential protection (DIFL)
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This command is found in the menu under:
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This command must be saved in order to be activated. Observe that
the command 5HOHDVH/RFDO will allow the trip outputs to be acti-
vated during the tests.
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The injected operation value must correspond to the set IMinOp·
Ir·CTFactor. This value is to be read as IDiffL1 and IDiffL2, and
50% of IDiffL1 as IBiasL1 and IBiasL2. The IDiffL3 should be
zero and IBiasL3 25% of IDiffL1. These values are read on the
HMI under:
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The result shall be transposed one, respectively two steps.
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The IMinOp·Ir·CTFactor value shall be obtained for operation and
read for I in all three phases. 100% of I
Diff
in all three phases.
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This command is found in the menu under:
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This delay is not allowed to exceed 12 ms.
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shall be read for I
Diff Bias
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