Toshiba GR200 Series Instruction Manual page 107

underreach setting in enough to the zone1
Figure 2.1-58 Line CJ tapped at junction J
Setting for the primary zone (Zone1 and a shot tapped line)
(iii)
Suppose the busbar C is tapped at the junction J on the line AB, as shown in Figure 2.1-59. 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 2.1-59 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.
.
(S)
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
- 86 -
Busbar B
Line BJ
U
Fault
Busbar B
Line AJ
U
Busbar B
U
Busbar C
6F2S1915 (0.46)
CTI
TZ3
TZ2
X
TZ1
S
TZR1
GRZ200 (Soft 031 & 032)
Zone1(S)