Toshiba GR200 Series Instruction Manual page 176

source does not exist behind busbar B. Accordingly, as for the fault on the line AB, the user
should have underreach setting in enough to the zone1
Figure 2.10-58 Line CJ tapped at junction J
Setting for the primary zone (Zone1 and a short tapped line)
(iii)
Suppose the busbar C is tapped at the junction J on the line AB, as shown in Figure 2.10-59.
It is required to have the reach setting in both the zone1(S) and the zone1(U) so as to hold a
part of the entire length of the line as shown in the long-dashed-short-dashed -circle line to
avoid unwanted operations for external faults at busbar C. Consequently, clearing faults by a
delayed zone2 are performed mostly, as shown in the broken-circle line that is operated at an
end of the line AB†.
Figure 2.10-59 Short line CJ tapped at junction J
†Note: To solve the problem, we recommend using the distance carrier command
protection or the current differential protection for the multi-terminals line shown
in the dotted-circle line.
Busbar A
J
Line AJ
S
Line CJ
O
Busbar C
Busbar A
J
Line FJ
S
Line JK
O
Busbar C
Busbar A
S
O
long-dashed-short-dashed-circle line
broken-circle line
dotted-circle line
- 153 -
.
(S)
Busbar B
Line BJ
U
Fault
Busbar B
Line AJ
U
Busbar B
U
Busbar C
6F2S1914 (0.49)
CTI
TZ3
TZ2
X
TZ1
S
TZR1
GRL200 (Soft 033 & 037)
Zone1(S