Toshiba GRL100-701B Instruction Manual page 123

Permanent fault
When reclose-onto-a-fault is activated when a permanent fault exists, three-phase final
tripping is performed. However, this operation is performed only in the single-shot
autoreclose mode. In the multi-shot autoreclose mode, reclosing is retried as shown below,
for multi-shot autoreclosing.
Multi-shot autoreclose
In a multi-shot autoreclose, low-speed autoreclose is executed up to three times after
high-speed autoreclose fails. The first shot is high-speed autoreclose that functions in the
same manner as described for single-shot autoreclose. Figure 2.15.2.6 shows the simplified
scheme logic for the low-speed autoreclose of the second to fourth shot.
[ARC-SM]
+
"S2", "S3", "S4"
ARC1
&
TP
F/F
ARC1
ARC2
≥ 1
ARC3
FT
SYN-OP
The multi-shot mode, two shots to four shots, is set with the scheme switch [ARC-SM].
In low-speed autoreclose, the dead time counter TS2 for the second shot is activated if
high-speed autoreclose is performed (ARC = 1), but tripping occurs again (TP = 1). Second shot
autoreclose is performed only when the voltage and synchronism check element operates
(SYN-OP = 1) after the period of time set on TS2 has elapsed. At this time, outputs of the step
counter are: SP1 = 1, SP2 = 0, and SP3 = 0.
Autoreclose is completed at this step if the two-shot mode is selected for the multi-shot mode.
Therefore, the tripping following the "reclose-onto-a-fault" becomes the final tripping (FT = 1).
If the voltage and synchronism check element does not operate within the period of time set on
the timer TS2R which is started at the same time as TS2 is started, the multi-shot autoreclose is
cancelled (FT = 1).
F/F
FT
≥1
MSARC
F/F
MSARC1
FT
≥ 1
SP1
SP2
&
SP1
F/F
MSARC2
≥ 1
FT
&
SP2
F/F
MSARC3
≥ 1
FT
[ARC-SM]
FT1
"S2" &
FT2
SP1
"S3"
&
SP2
"S4"
&
SP3
Figure 2.15.2.6 Scheme Logic for Multi-Shot Autoreclose
 122 
1
TS2
t 0
&
5 - 300s
TS2R
t 0
5 - 300s
TS3
t 0
&
5 - 300s
TS3R
t 0
5 - 300s
TS4
t 0
&
5 - 300s
TS4R
t 0
5 - 300s
≥ 1
≥ 1
FT3
6 F 2 S 0 8 5 0
STEP COUNTER
SP1
CLR
SP2
CLOCK
SP3
0
≥ 1 t
MSARC1
0.1s
MSARC2
MSARC3
FT
0.5s
MSARC