Directional Blocking Scheme - Siemens SIPROTEC 7SA6 Manual

Functions
EF Telep. off
FNo 1313
>EF TeleprotBLK
Transient blocking
Trip command
EF forwards
EF Pickup
FNo 1320
>EF UB ub 1
&
FNo 1321
1
>EF UB bl
&
Line Config.
FNo 1322
>EF UB ub 12
&
FNo 1323
2
>EF UB bl
&
„1"
Figure 6-82 Logic diagram of the unblocking scheme (one line end)
6.8.1.3

Directional Blocking Scheme

Principle
6-146
≥1
Send Prolong.
&
&
Release Delay
10
20
≥1
3202
Two terminals
10
Three terminals
Two terminals
Three terminals
Two terminals
Three terminals
The following scheme is suited for conventional transmission media.
In the case of the blocking scheme, the transmission channel is used to send a block
signal from one line end to the other. The signal transmission is started as soon as a
fault in reverse direction is detected, optionally also right after fault inception (jump de-
tector via dashed line). It is stopped as soon as the earth fault protection detects a fault
in forward direction, alternatively the signal is only sent when the earth fault protection
detects the fault in the reverse direction. On the other hand the signal will be main-
tained if the fault is in reverse direction. If the signal is sent with jump detections (i. e.
1390 EF Tele BL Jump is routed in parallel with 1384 EF Tele SEND ), only a short
delay to allow for signal transmission is required before the directional E/F trips. Trip-
ping is possible with this scheme even if no signal is received from the opposite line
end. It is therefore mainly used for long lines when the signal must be transmitted
across the protected feeder by means of power line carrier (PLC) and the attenuation
of the transmitted signal at the fault location may be so severe that reception at the
other line cannot necessarily be guaranteed.
&
3203
0 T
≥1
3208
T 0
≥1
&
0
s
0 100 100
ms ms
0
s
&
≥1
FNo 1381
EF Telep. OFF
FNo 1384
&
EF Tele SEND
Echo function
&
section 6.8.1.5
≥1
FNo 1387
EF TeleUB Fail1
&
EF Enable TripS
FNo 1388
EF TeleUB Fail2
Week-Infeed
&
≥1
acc. Fig. 6-89
C53000-G1176-C156-2
tripping
7SA6 Manual