Toshiba GR200 Series Instruction Manual page 79

CBF operation by faults occurrence
2.2.4
Target CB tripped normally
(i)
Figure 2.2-7 shows a timing chart for the operation of the CBF protection when the target CB†
trips normally. Timers TCBF-RE_CH* and TCBF-ZONE_CH* are initiated by the trip
command following the occurrence of a fault, however a CBF re-trip and a CBF Zone-trip will
not occur because the OCCBF relay is reset before timers CBF re-trip and CBF Zone-trip time
out.
Fault
Fault current
Closed
Adjacent CB
Open
Closed
Target CB
Open
GEN.TRIP
OCCBF_CH* relay
Re-trip
Zone-trip
TCB: operating time of the target CB
TOC: reset time of the OCCBF element in CH*
Figure 2.2-7 CBF operation chart (Target CB tripped normally)
†Note: For example, the target CB is "CB11" when the CBF function is introduced in
Table 2.2-3 and the adjacent CBs are "CB12" and "CBC" in Table 2.2-3.
TCB
TOC
Timer set with [TCBF-RE_CH*]
Timer set with [TCBF-ZONE_CH*]
- 65 -
'OCCBF relay' resets before TCBF-RE timer elapses.
'OCCBF relay' resets before TCBF-ZONE timer elapses.
Centralized GRB200
(Soft: 030, 031, 032, 033, 034)
6F2S1931 (0.20)