ABB Relion 670 Series Applications Manual page 148

Section 6
Differential protection
In addition to busbar protection differential zones, the IED can incorporate other additional functions and
features. If and how they can be used together with summation busbar protection design is shown in
Table 25:
Table 25:
Functions
Busbar Differential Protection
Dynamic Zone Selection feature
CCRBRF/CCSRBRF function
OC4PTOC/PHS4PTOCfunction
OC4PTOC/PHS4PTOC function
DRPRDRE function
DRPRDRE function
DRPRDRE function
Communication
SMBRREC function
142
Functions
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Comment
Differential Protection, Sensitive differential protection, OCT algorithm, Check
Zone and Differential Supervision features will be connected to the summated
bay currents. Therefore, they will have different level depending on the type of
fault and involved phase(s). For more information, refer to Table 24. However,
if all these limitations are acceptable it is still possible to use all these internal
busbar protection features. Note that OCT operating logic will not work
properly in case of opening or shorting the main CT secondary leads (that is,
in-between main CT and ASCT). In case of opening or shorting the ASCT
secondary leads (that is, in-between ASCT and the IED) the OCT logic will
operate correctly.
Zone Selection feature in the IED can be used in the exactly same way as
with phase segregated design. All built-in features, even including breaker
failure protection, protection back-up trip command routing, EnFP logic can
be used in the exactly same way as for phase segregated design.
Breaker Fail Protection function will be connected to the summated bay
current. Therefore it will have different pickup level depending on the type of
fault and involved phase(s). See Table
to have individual initiation per phase, but only three-phase initiation can be
effectively used. However, if all these limitations are acceptable it is still
possible to use internal CCRBRF/CCSRBRF functions.
Overcurrent Protection function will be connected to the summated bay
current. Therefore, it will have different pickup level depending on the type of
fault and involved phase(s). See Table
difficult to insure proper pickup and time grading with downstream overcurrent
protection relays. Hence it will be quite difficult to use OC4PTOC/PHS4PTOC
as backup feeder protection with summation design.
End Fault Protection feature will be connected to the summated bay current.
Therefore it will have different pickup level depending on the type of fault and
involved phase(s). See Table
PHS4PTOC do not need any pickup or time coordination with any other
overcurrent protection. Thus if above limitations are acceptable OC4PTOC/
PHS4PTOC can be used with summation design.
Disturbance Recording feature will be connected to the individual summated
bay current. Therefore recorded currents will not correspond to any actual
primary currents. However such DRPRDRE records can still be used to
evaluate internal busbar protection, CCRBRF/CCSRBRF and OC4PTOC/
PHS4PTOC protections operation.
Event List feature in the IED can be used in the exactly the same way as with
phase segregated design.
Trip Value Recording feature will be connected to the individual summated
bay current. Therefore recorded trip current values will not correspond to any
actual primary currents. However such records can still be used to evaluate
internal busbar protection, CCRBRF/CCSRBRF and OC4PTOC/PHS4PTOC
protections operation.
All communication features in the IED can be used in the exactly the same
way as with phase segregated design
Autoreclosing function in the IED can be used in the exactly same way as
with phase segregated design.
1MRK 505 370-UUS Rev. K
24 for more info. It will not be possible
24 for more info. Thus it will be very
24 for more info. However, OC4PTOC/
Busbar protection REB670
Application manual
SEMOD127594-37 v4