10
Fig. 8. Determination of the checking time for closing.
Closing is permitted during the time t
check
start-
ing from the moment when the external com-
mand signal CS13 is activated. The external
command signal has to be active during the
whole pre-set checking time, that is, when the
length of the external command signal to be de-
livered to the supervision stage is determined,
the value of the set t
check
time must be consid-
ered too. If the closing command conditions get
fulfilled during the t
check
time, a closing signal
is delivered to the circuit breaker. If the closing
conditions are not fulfilled during the checking
time, the alarm NC13 is activated for 500 ms
as an indication of a failed closing attempt. If
the closing conditions do not become valid un-
til after the t
check
time, no closing signal is de-
livered. The closing signal is delivered only once
per activated external command signal. A new
closing command sequence cannot be started
until the external command signal has been re-
set and then activated again.
By removing the external command signal too
early the started closing command sequence can
be interrupted and the supervision stage can be
reset to original state. If the command signal
CS13 is removed before the checking time t
check
has elapsed and the closing operation has not
been enabled, the sequence resets and no alarm
of the failed closing attempt is delivered. The
activation of the external command signal again
starts a new checking sequence.
Settings for the
command mode
operation
The checking time t
check
determines the time
after which closing of the circuit breaker is per-
mitted. The checking time starts after activa-
tion of the external command signal and the
signal shall be active during the total checking
time.
The maximum length of the closing signal in
the command mode operation is determined by
the set t
pulse
time.
The closing signal may even be shorter depend-
ing on whether the external command signal
delivered to the stage is removed before the set
maximum t
pulse
time has elapsed.
The alarms in the command mode operation
are enabled or disabled by means of the func-
tional switchgroup SGR.
500 ms
cond13
CS13
BS13
CB13
NC13
check
t
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