ABB Relion 670 Series Applications Manual page 109

1MRK 505 370-UUS Rev. K
• 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 both when normally open and normally closed (that is, "a"
and "b" contacts) 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.
This setting is typically used for feeder bays in double busbar single breaker stations in order to form
proper busbar disconnector replica. It is especially suitable when only normally closed (that is, "b"
contact) auxiliary contact from the busbar disconnector(s) is available to the IED. For more information
please refer to Figure 64.
6.1.3.6 CT disconnection for bus interconnector CT cores
For simplicity purpose, sometimes we also refer to a bus-section or bus-coupler bay as a bus
interconnector bay. In practice there are three different solutions for bus interconnector bay layout. First
solution is with two sets of main CTs, which are located on both sides of the circuit breaker, as shown in
Figure 46.
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ANSI01000013 V1 EN-US
Figure 46:
Two differential zones are overlapping across the bus-section or bus-coupler circuit breaker. All faults in
the overlapping zone will be instantly tripped by both zones irrespective of the section/coupler circuit
Busbar protection REB670
Application manual
ZA
2 8
Example of station with two sets of main CTs in the bus-section bay
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ZB
BS
1 2
Differential protection
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