ABB REB670 Applications Manual page 118

Section 6
Differential protection
112
1. FIXEDtoZA
2. FIXEDtoZB
3. FIXEDtoZA&-ZB
4. CtrlIncludes
5. CtrlExcludes
If for a particular CT input setting parameter ZoneSel is set to FIXEDtoZA, then this CT
input will be only included to the differential zone A. This setting is typically used for
simple single zone application such as: single busbar staions, breaker-and-a-half stations
or double breaker stations.
If for a particular CT input setting parameter ZoneSel is set to FIXEDtoZB, then this CT
input will be only included to the differential zone B. This setting is typically used for
applications such as: breaker-and-a-half stations or double breaker stations.
If for a particular CT input setting parameter ZoneSel is set to FIXEDtoZA&-ZB, then this
CT input will be included to the differential zone A, but its inverted current value will be
as well included to the differential zone B. This setting is typically used for bus coupler or
bus section bays when only one current transformer is available see figure 44.
If for a particular CT input setting parameter ZoneSel is set to Ctrl_Includes, then this CT
input will be:
• included to the differential zone A when input signal CTRLZA on corresponding bay
block is given logical value one and it will be excluded from the differential zone A
when input signal CTRLZA on corresponding bay block is given logical value zero.
• included to the differential zone B when input signal CTRLZB on corresponding bay
block is given logical value one and it will be excluded from the differential zone B
when input signal CTRLZB on corresponding bay block is given logical value zero.
This setting is typically used for feeder bays in double busbar stations in order to form
proper busbar disconnector replica. It is especially suitable when normally open and
normally closed (that is, a and b) auxiliary contacts from the busbar disconnectors are
available to the IED.
If for a particular CT input setting parameter ZoneSel is set to Ctrl_Excludes, then this CT
input will be:
• excluded from the differential zone A when input signal CTRLZA on corresponding
bay block is given logical value one and it will be included to the differential zone A
when input signal CTRLZA on corresponding bay block is given logical value zero
• excluded from the differential zone B when input signal CTRLZB on corresponding
bay block is given logical value one and it will be included to the differential zone B
when input signal CTRLZB on corresponding bay block is given logical value zero
1MRK 505 337-UUS -
Application manual