Blocking Scheme - Siemens siprotec 7SA522 User Manual

4032 >Dis.T.UB ub1L1
4033 >Dis.T.UB ub1L2
4034 >Dis.T.UB ub1L3
4030 >Dis.T.UB ub 1
4031
>Dis.T.UB bl 1
4035
>Dis.T.UB ub 2
4036 >Dis.T.UB bl 2
Figure 6-51 Unblock–logic
6.4.1.5

Blocking scheme

Principle
7SA522 Manual
C53000-G1176-C119-2
&
20 0
&
ms
&
20 0
&
ms
&
20 0
&
ms
&
20 0
&
ms
&
20 0
&
ms
The blocking scheme uses the transmission channel to send a block signal from one
line end to the other. The signal may be sent directly after fault inception (jump detec-
tor), and stopped immediately, as soon as the distance protection detects a fault in the
forward direction, alternatively the signal is only sent when the distance protection de-
tects the fault in the reverse direction. The signal will be maintained if the fault is in
reverse direction. If the signal is sent with jump detection (i.e.  'LV-XPS%ORFN
LQJ routed in parallel with  -  ) only a short delay to allow for signal trans-
mission is required before Z1b trips. A trip can be achieved with this scheme even if
no signal reaches the opposite end. It is therefore mainly used on long lines, when the
signal must be transmitted via the protected line with power line carrier (PLC), and the
≥1
&
100 100
ms
10 0
s
≥1
&
100 100
ms
10 0
s
≥1
&
100 100
ms
10 0
s
≥1
&
100 100
ms
10 0
s
≥1
&
100 100
ms
10 0
s
Functions
Unblock L1
Unblock L2
Unblock L3
Unblock 1
≥1
4080
Dis.T.UBFail1
Unblock 2
4081
Dis.T.UBFail2
6-87