Siemens 7SG164 Ohmega 400 Series Manual page 147

BOR
Title Blocking Overreach Type 2 Scheme using reverse Zone 4 for blocking and aided Zone 2 tripping
Art No 2615S81121
Author Ken Nickerson
Clear the reach extension controls as that scheme is not in use.
FALSE
Firstly, the general trip logic for normal zone operations
Z1D
Z2D
Z3D
Next, w e generate a blocking signal if Zone 4 operates. Zone 4 is reverse looking, so blocks out-of-zone (reverse) faults
Also, w e add the external unstabilise control (Manual/external trip) into the equation to allow it to w ork w ith the scheme.
Z4G
UNSTABILISE
Now w e generate the aided trip signal, w hich is delayed to allow time for blocking, and is blocked if signal receive is active.
Also, w e need an inhibit signal to prevent blocking under certain circumstances, and to incorporate the carrier fail signal.
CARRIERFAIL
SREXTEND
SIGRECV1
1 / 1
BLOCKINHIBIT
Z2G
©2011 Siemens Protection Devices Limited
Z1XEF
Z1XPF
1
SSEXTEND
&
0 / 1
1
&
PTTimer
20 / 1
7SG1641 Ohmega 402 60 Diagrams
SOLOTRIP
1 SIGSEND1
Also, generate an output tag so that the
signal receive input can generate a flag
&
&
AIDEDTRIP
Chapter 11 Page 18 of 18