ABB SPAC 315 C User Manual And Technical Description page 31

+Uc
66
OPEN
I>
97
96
OPEN
65
-Uc
Fig. 1. Operating principle of the supervision function of the trip circuit
The supervision of the trip circuit is based on
the constant current injection principle. If the
resistance of the trip circuit, e.g. because of loose
contacts or oxidation, exceeds a certain limit or
if the OPEN contact has welded, the voltage
over the OPEN contact goes below 30 V dc and
the supervision function of the trip circuit is
activated. If the fault persists, a trip circuit su-
pervision alarm signal in the form of a flashing
"O.C.F." message (Open Circuit Fault) on the
display is obtained after the preset 3 s delay time.
By default the alarm signal is connected to the
alarm output contact SIGNAL 4. If this output
contact is already used as an alarm output of
e.g. earth fault protection, by setting parameter
S200= 2, the trip circuit supervision alarm can
be configured so that only display alarm and
event is generated.
The fault message can be locally acknowledged
by pressing the push-buttons STEP and SE-
LECT ∩ simultaneously for about 1 s.
SG1/2=0
S200>0
I
U>30V
Rh(ext)
O
Rh(int)
3s
&
STEP+
Note!
Only the display indication needs acknowledg-
ing, not the alarm signal output. The alarm
output will reset automatically when the fault
disappears.
As a default and to avoid unnecessary alarms,
the function of the trip circuit supervision is
blocked when the trip signal TS2 initiated by
the protection module is activated, that is when
the OPEN contact is closed. The trip circuit
supervision is also automatically disabled when
the circuit breaker is withdrawn, i.e. when the
four-pole status of both CB and CB truck indi-
cate "undefined" status (no voltage at binary
status inputs). . The CB truck is defined by value
"11" for object type on the configuration com-
mand line. Further, in case of removed CB, the
flashing position indicators of CB and CB truck
showing undefined status, can be set to be
switched off after 10 min timeout. This can be
done with parameter S7.
SIGNAL4
S200=1
O.C.F.
SPAC 3__
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