Transient Blocking - Siemens siprotec 7SA6 User Manual

Functions
6.6.1.4

Transient Blocking

6-128
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
"!" TrqÃQ…‚y‚tÃ
3IoMin Teleprot
EF forward
"!!
1318 >EF Rec.Ch1
1319 >EF Rec.Ch2
3208
EF Pickup
Figure 6-76 Logic diagram of the blocking scheme (one line end)
Transient blocking provides additional security against erroneous signals due to
transients 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 6-77 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 7U%ON :DLW 7LPH
(address  ) following fault detection, the transmit circuit and the trip release are
inhibited. This blocking is maintained for the duration of the transient blocking time
7U%ON %ORFN7LPH (address ) also after the reset of the blocking criterion.
In the case of the blocking scheme, the transient blocking prolongs the received
blocking signal as shown in the logic diagram Figure 6-76.
≥1
&
40 ms
0 T
&
&
GvrÃ8‚svtÃ
≥1
Three terminals
Two terminals
Sryrh†rÃ9ryh’
T 0
"!( U…7yxÃXhv‡ÃUv€r
"!  U…7yxÃ7y‚pxUv€rÃ
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-C133-1