Toshiba GR200 Series Instruction Manual page 154

Undervoltage elements (UVLS or UVLG) being operated.

Neither forward overreaching element nor reverse looking element being operated.

From PROT COMMON
UVLG-A
UVLG-B
UVLG-C
UVLS-AB
UVLS-BC
UVLS-CA
DEAD_LINE_DEDTECT
DISCAR_PARM1-A
DISCAR_PARM1-B
DISCAR_PARM1-C
DISCAR_PARM1
From CARRIER-COMMON
CH1-USE
DISCAR_PARM1-A
DISCAR_PARM1-B
DISCAR_PARM1-C
DISCAR_PARM1
From CARRIER-COMMON
CH2-USE
ECHO1_CONDITION
On
DIS-WKIT
810000EBBE DIS-WKIT BLOCK
From CARRIER-COMMON
WKIT-A_CONDITION
WKIT-B_CONDITION
WKIT-C_CONDITION
Dis-CAR
UV responds to three phase-to-phase voltages and three phase-to-ground voltages. UV
prevents false weak infeed tripping due to spurious operation of the channel.
WIKT can be enabled using scheme switch [Dis-WKIT] On.
Countermeasure for current reversal
2.3.6
When a fault occurs on one of the parallel lines, the reversal of fault current may be found on
another line owing to sequential CB opening. In the worst case, the current reversal can result
in false operation in POP, UOP and BOP. Thus, POP, UOP and BOP have current reversal logic
(CRL) to prevent the false operation.
Figure 2.3-11(a) shows the arrangement of parallel lines, as an example. Suppose that a
fault occurs at location F on line L1 at time t1. CB A1 is tripped at time t2; and later, CB B1 is
tripped at time t3. The current direction on line L2 can be reversed at time t2. That is, the
current ( ) from terminal B to terminal A is found from time t1 to t2. However, the
current ( ) from terminal A to terminal B is found from time t2 to t3. The current
0 t
0 t
0 t
≥1
1
≥1
&
0.000 to 0.100 s
1
Figure 2.3-9 UV for WIKT
& &
≥1
& &
≥1
&
&
≥1
&
&
≥1
1
&
≥1
&
≥1
&
≥1
&
≥1
1
&
1
POP
UOP
≥1
Figure 2.3-10 WIKT logic
- 133 -
& WKIT-A_CONDITION
≥1
WKIT-B_CONDITION
≥1 &
≥1 WKIT-C_CONDITION
&
TWICOORD
t 0
≥1
&
≥1
&
≥1
&
≥1
6F2S1915 (0.46)
8000001B6F
DISCAR_WITIP-A
8100001B70
DISCAR_WITIP-B
8200001B71
DISCAR_WITIP-C
8300001B72
DISCAR_WITIP
From Z1G
GRZ200 (Soft 031 & 032)