Toshiba GR200 Series Instruction Manual page 222

Figure shows CRL logic. CRL logic can determine the current reversal when the reverse
looking element runs and the forward looking element does not run. If the current reversal is
found, CRL declares for the opposite terminal to block the trip operation immediately. At the
same time, CRL blocks CB tripping at its own terminal. If the condition of current reversal
continues longer than 20ms, CRL lasts to run for setting [TREBK-Dis] even after the current
reversal ceases.
Forward looking element in phase A
Reverse looking element in phase A
Forward looking element in phase B
Reverse looking element in phase B
Forward looking element in phase C
Reverse looking element in phase C
Forward looking element in three-phase
Reverse looking element in three-phase
The operation of CRL and its effect in the current reversal are follows:
CRL at terminal A2 runs immediately after the fault occurs.
◼
The operation of CRL continues to last for another period of off-delay timer setting
◼
[TREBK-dis] even after the reverse looking element does not run and the forward
looking element runs; CRL continuously blocks the local tripping and transmitting a
trip block signal to terminal B2.
Even if operation overlap of the forward looking elements between terminal A2 and
terminal B2 arises due to the current reversal, the operation overlap will disappear during the
operation of CRL. Thus, the false operation on the healthy line of parallel lines can be removed.
When the current reversal occurs in the direction opposite to the above, CRL at terminal B2
will respond similarly.
CRL does not pick up for internal faults; thus, high-speed operation of any protection
scheme is not obstructed.
Carrier signal reception
2.12.7
IED has two types of carrier signal transmission style. One is the general style of outputting
and sending a carrier signal from a binary output and receiving it from a binary input. It is
called "external carrier communication". The other is a special style that uses the transmission
control function (DIF_COMM) to send and receive carrier signals, which can only be used with
IEDs that has the DIF_COMM function. It is called "integral carrier communication".
Figure 2.12-13 shows how to receive carrier signals from the remote terminal 1. In the external
t
1
&
0.02s
t
1
&
0.02s
t
1
&
0.02s
t
1
&
0.02s
Figure 2.12-12 Current reversal logic
- 199 -
TREBK-Dis
8000001B64
0 0 t
DIS-REVBLK-A
≥1
-CX
0.00-10.00s
TREBK-Dis
8100001B65
0 0 t
DIS-REVBLK-B
≥1
-CX
0.00-10.00s
TREBK-Dis
8200001B66
0 0 t
DIS-REVBLK-C
≥1
-CX
0.00-10.00s
TREBK-Dis
8300001B67
0 0 t
DIS-REVBLK-S
≥1
-CX
0.00-10.00s
6F2S1914 (0.49)
GRL200 (Soft 033 & 037)