ABB REL 356 Current Differential Protection
3-30
Settings and Application
Backup System Settings – Versions with Distance Option only
Backup System Enable (BKUP)
BKUP = CT
This setting determines if and when the distance backup system will be activated. There are three possible BKUP
settings:
BKUP = NONE
The backup distance system, even though included, will be deactivated at all times and will not
trip.
BKUP = CT
The backup distance system will be activated 150 msec after a CT (channel trouble) condition
occurs. It will stay enabled until the channel comes back into service when it will automatically
be switched out.
BKUP = CTDD
The backup distance system will be activated 150 msec after a CT (channel trouble) condition
occurs or a differential protection disable condition occurs. Differential protection disable can
be activated by a energizing a local or remote input. The backup system will stay enabled until
the channel comes back into service or the disable condition resets and will then automatically
be switched out.
Loss of Potential Block (LOPB)
LOPB = NO
This setting enables the loss of potential logic (V0 and notI0) to block all Zone 2 and Zone 3 impedance units if the logic
is satisfied.
The loss of potential logic does not affect the differential protection which uses currents only.
Directional Units Settings
Forward Directional Phase Unit (FDOP)
FDOP = IN
If the system has voltage inputs, then the high set phase overcurrent units (IPH) can be made directional if FDOP is set
to IN.
Forward Directional Ground Unit (FDOG)
FDOG = IN
If the system has voltage inputs, then the high set ground overcurrent unit (IPG) can be made directional if FDOG is set
to IN.
Ground Directional Unit Polarization (DIRU)
DIRU = ZSEQ
The ground directional unit can be zero sequence or negative sequence polarized. When zero sequence polarized, it
uses all zero sequence quantities to determine the power flow direction and is sensitive to zero sequence mutuals
between parallel lines. When negative sequence polarized it uses all neagtive sequence quantities to determine the
power flow direction and its operation is not influence by mutual effects. Set DIRU = ZSEQ if mutuals are not a
consideration and DIRU = NSEQ if strong zero sequence mutuals are present for the transmission line.
Ground Backup Unit Settings – Versions with Distance Option only
Medium Set Ground Overcurrent Unit (IOM)
IOM = 0.5 A
This overcurrent unit supervises the trips of the ground units in the impedance backup system. If TOG is set, it is also
used for tripping after a time delay. The IOM unit measures 3I0 and should be set above maximum unbalance during
load conditions.
The recommended setting is IOM = 0.5 A.
Summary of Contents for REL 356
Page 23: ...ABB REL 356 Current Differential Protection 1 10 Product Overview and Specifications ...
Page 83: ...ABB REL 356 Current Differential Protection 3 36 Settings and Application ...
Page 127: ...ABB REL 356 Current Differential Protection 5 28 Testing ...
Page 186: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 49 of 53 ...
Page 187: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 50 of 53 ...
Page 188: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 51 of 53 ...
Page 189: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 52 of 53 ...