3.4 Load pulse and parallel command
When none of the following thresholds: DUb, DUg, DU, Dfb, Dfg,
tripping, the protection sends a parallel command with
a pulse duration equal to tc; the command is sent with a n
advance time equal to tr (breaker trip time) compared to the
expected Dp=0 phase difference instant: this to
to be closed just when the voltages are in phase with each other.
If after the twc time the breaker is not closed (corresponding
digital input enabling failed) and the parallel conditions are still
acceptable, a further closing comma
nd is sent; the max. number
of commands is defined by the set Ns.
If after the last attempt the breaker is not closed, the 'failed
ce' command - once the max. number of
attempts has been reached - as well as any signal corresponding
to the event will be sent; the partial and total counter relative to the
event is incremented and the event logging is enabl
synchronization sequence' command - following a timeout
condition - as well as any signal corresponding to the event will
sent; the partial and total counter relative to the mentioned event
is incremented and the event logging is enabled.
'breaker closed' signal, the 'correctly-performed
Together with the 'breaker closing' command, in the event of LP
mode, a frequency increase pulse is issued for
time duration equal to tlp. This frequency increase pulse and,
The device can even be used to feed an out-of-voltag
the generator parameter can
The sequence start occurs upon enabling the digital input
associated with a DB start (with enabling characteristic on
The dead-bar level is defined by the Ud set value; below the said
value the bar is considered as not-fed.
Any request of dead-bar synchronization is ignored.
that the generator frequenc
within the limits defined by Dfg
and DUg, by controlling the parallel
breaker closing without carrying out any adjusting action.
The device works by comparing the fb bar frequency with the fn
When the deviation between the two frequencies exceeds theDfb
set value, the 'START reques
t failed' command - due to
of-tolerance condition - as well as
any signal corresponding to the
mentioned event is incremented and the
event logging is enabled.
d frequency/ generator frequency
The device works comparing the fg generator frequency with the
When the deviation between the two frequencies exceeds the Dfg
set value, the 'START reques
of-tolerance condition - as well as
any signal corresponding to the
event, are sent; the partial and total counter relative to the event
is incremented and the event logging is enabled.
3.3.3 Max. frequency difference
The device works by comparing the fb bar frequency with the fg
When the difference between the
two frequencies exceed the
set value, the 'frequency increase' (if fg<fb) or 'frequency decrease'
(if fg>fb) command is sent.
The frequency increase/decrease commands can be of
'continuous' or 'pulse' type depending on the
has been set, that is CPf CONT or PULSE.
mode has been set, the pulse time is defined by the
tfpu set parameter; the min. pulse interval is given by the tfpa set
If the phase difference between bar and generator constantly
above the Dp set threshold,
after a time interval equal to tfpm has
since the last frequency increase/d
the following types of desynchronization commands will be sent:
'frequency increase' in the event of SUPERSYNC live
mode or 'frequency decrease' in the
parallel mode; in case of NORM live bar parallel mode the
d will be sent when the generator is in 'delay'
condition compared to the bar, whereas the 'decrease' command
the generator is in 'advance' condition.
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