ABB RELION 670 Series Applications Manual page 108

Section 6
Differential protection
If for a particular CT input setting parameter
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
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
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
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
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) auxiliary contact from the busbar disconnector(s) is available to the IED. For more
information please refer to figure 63.
In applications where zone selection (that is, CT switching) is required (for example double or
multiple busbar stations) all CTs will be permanently connected to the analogue input module(s),
as shown in figure 62. Therefore, all necessary switching of currents will be performed in internal
software logic.
6.1.3.9 CT disconnection for bus section and bus coupler current transformer cores
In practice there are three different solutions for bus section or bus coupler 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 43.
102
ZoneSel is set to FIXEDtoZA , then this CT input will
ZoneSel is set to FIXEDtoZB , then this CT input will
ZoneSel is set to FIXEDtoZA&-ZB , then this CT input
ZoneSel is set to Ctrl_Includes , then this CT input will
ZoneSel is set to Ctrl_Excludes , then this CT input will
1MRK 505 337-UUS A
M12113-3 v3
Application manual