ABB Modures LZ91 - Page 26

switch
6b
switch
7
switch 8a
switch Sb
plug-in link
plug-in link
Ba
Sb
position 1
position 2
position
1
position 2
position 1
position 2
position 1
position 2
position 1
position 2
position 1
position 2
k =
0.1
kt
1
t
t
~
t4
4
_.
8b
t ~
I -
I --
I
--
-
t
~
_J_~_...J
1-----t
PUTT
multiplier for the
3rd. time step
multiplier for the 3rd. time
step
zone 4
directional
zone 4 non-directional
direction has indicated on Sb
direction as indicated on Sb, but
~ zone reversed (see Section 3.6).
Switch 8a is not fitted in all
versions.
reverse direction
forwards direction, if relay connected
as in our diagram.
direction
as
set on
I~
on the front-
plate
direction
as
set on
I~
on the front-
plate, but one zone reversed.
overreaching (intertripping scheme,
see Section
3 .10)
permissive
underreaching
transfer
tripping (where fitted) .
3.10 Main processing unit equipped for intertripping schemes
Main processing units with PCB 8 acc. to HESG 440 718 (see Section 3.12) are
equipped as standard with the auxiliary components for operating in intertrip-
ping schemes. On these units either an acceleration scheme (zone extension) or
permissive underreaching transfer tripping can be selected using plug-in link
Sb on PCB 8 (see Fig. 9.31). In the case of an acceleration scheme a signal
from the opposite station causes the receiving relay to switch to overreach-
ing, whilst in the permissive underreaching scheme the relays have a normal
underreaching setting and the receiving relay trips, providing a starting unit
has picked up. In special cases the PUTT scheme can also include the directio-
nal measurement of the receiving relay (soldered link LB20, see Fig. 9.32).