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Functions
6.8.1.4
Transient Blocking
6-148
EF Telep. off
1313 >EF TeleprotBLK
EF TeleTransBlk
, I
, I
d
I
(u,i)
L1
L2
L3
dt
U
, U
, U
(A)
L1
L2
L3
3203 Send Prolong.
3IoMin Teleprot
EF forward
3202
1318 >EF Rec.Ch1
1319 >EF Rec.Ch2
3208 Release Delay
EF Pickup
Figure 6-84
Logic diagram of the blocking scheme (one line end)
Transient blocking provides additional security against erroneous signals due to tran-
sients caused by clearance of an external fault or by fault direction reversal during
clearance of a fault on a parallel line.
The principle of transient blocking scheme is that following the incidence of an external
fault, the formation of a release signal is prevented for a certain (settable) time. In the
case of permissive schemes, this is achieved by blocking of the transmit and receive
circuit.
Figure 6-85 shows the principle of the transient blocking for a directional comparison
and directional unblocking scheme.
If a fault in the reverse direction is detected within the waiting time TrBlk Wait Time
(address 3209A ) following fault detection, the transmit circuit and the trip release are
inhibited. This blocking is maintained for the duration of the transient blocking time
TrBlk BlockTime (address 3210A ) also after the reset of the blocking criterion.
In the case of the blocking scheme, the transient blocking prolongs the received block-
ing signal as shown in the logic diagram Figure 6-84.
≥1
&
40 ms
0
T
&
&
Line Config.
≥1
Three terminals
Two terminals
T
0
3209 TrBlk Wait Time
3210 TrBlk BlockTime
1381
EF Telep. OFF
1390
EF Tele BL Jump
&
1384
EF Tele SEND
&
1384
EF Tele BL STOP
&
EF Enable Trip
&
1386
EF TeleTransBlk
T
T
7SA6 Manual
C53000-G1176-C156-2
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