ABB SPAU 140 C User Manual And Technical Description page 28

Command mode
operation
8
In command mode operation an external com-
mand signal, besides the normal closing condi-
tions, is needed for delivering of the closing sig-
nal. The command signal shall be active as long
as the set checking time. The closing signal from
the supervision stage can be blocked by apply-
ing the blocking signal to the stage. The func-
tion of the blocking input is selected by means
of selector switchgroup SGB.
In the command mode operation the synchro-
check relay itself controls the selected object di-
rectly via its own output signal. In this case the
control module delivers the command signal for
closing to the synchro-check relay for releasing
SC Synchro-check relay
CM Control module
Command signal
CM
Fig. 5. A simplified block diagram of the synchro-check relay in command mode operation.
The closing signal in the command mode op-
eration is pulse-shaped and the maximum length
of the closing signal can be set. The closing sig-
nal is delivered only once per activated external
closing command signal. The duration of the
delivered closing signal is at least 100 ms, how-
ever, not longer than the set maximum param-
eter value. The minimum length of the signal
depends on the duration of the delivered exter-
nal command signal and the duration of the
valid closing conditions. If the delivered com-
mand signal disappears or the closing conditions
end before the maximum length of the com-
mand signal, the output resets and the closing
signal will be shorter than the set parameter
value, however, at least 100 ms. If the external
closing command signal and the closing condi-
tions persist longer than the length of the set
closing signal, the closing signal will have the
length of the set parameter value.
A valid time, after which the closing operation
is going to be performed, is determined for the
external closing command signal to be deliv-
ered. In that way a closing command sequence
started can be limited to a certain length regard-
less of if the command signal, for example, stays
of a closing signal pulse to the circuit breaker.
If, after the delivered command signal for clos-
ing, the closing conditions are fulfilled during a
permitted check time, the synchro-check relay
delivers a closing signal to the circuit breaker.
Via a possible feedback of the circuit breaker
status the control module recognizes when the
command signal can be removed. In such a case
the duration of the command signal to be ap-
plied to the synchro-check relay is determined
by the operate time of the circuit breaker. If feed-
back of the circuit breaker status is not avail-
able, the duration of the command signal from
the control module is constant.
Closing signal
SC
active due to a fault. The function of the com-
mand mode operation is such that it is possible
to deliver an external alarm for divergent situa-
tions. In the command mode operation there
are alarms for a failed closing attempt and for a
command signal that remains active too long.
If the command signal delivered to the super-
vising stage is too long, an alarm is given and
the alarm state of the stage persists until the clos-
ing command signal is removed. A failed clos-
ing attempt produces an alarm signal of about
500 ms. After that the supervising stage is ready
for a new operation sequence.
The most essential features of the command
mode operation are shown in figures 6, 7 and 8.
Abbreviations used in the diagrams:
cond13 Closing conditions for stage 1
CS13 External closing command signal
for stage 1
BS13 External blocking input for stage 1
CB13 Closing signal delivered by stage 1
NC13 Alarm signal delivered by stage 1
CSF13 Alarm signal delivered by stage 1