Operation mode
Description
Freq< OR df/dt A parallel operation between the protection methods is en-
abled. The START output is activated when either of the
measured values of the protection module exceeds its set
value. Detailed information about the active module is avail-
able at the STR_UFRQ and STR_FRG outputs. The shortest
operate delay time from the set
Operate Tm Freq
or
Oper-
ate Tm df/dt
is dominant regarding the OPERATE output.
The time characteristic is according to DT. The characteris-
tic that activates the OPERATE output can be seen from
the OPR_UFRQ or OPR_FRG output. If the frequency gradi-
ent restores before the module operates, the reset timer is
activated. If the timer reaches the value set by the
Reset
delay Tm df/dt
setting, the operate timer resets and the
STR_FRG output is deactivated. If the frequency restores
before the module operates, the reset timer is activated. If
the timer reaches the value set by the
Reset delay Tm Freq
setting, the operate timer resets and the STR_UFRQ output
is deactivated.
Freq> OR df/dt A parallel operation between the protection methods is en-
abled. The START output is activated when either of the
measured values of the protection module exceeds its set
value. A detailed information from the active module is avail-
able at the STR_OFRQ and STR_FRG outputs. The shortest
operate delay time from the set
Operate Tm Freq
or
Oper-
ate Tm df/dt
is dominant regarding the OPERATE output.
The time characteristic is according to DT. The characteris-
tic that activates the OPERATE output can be seen from
the OPR_OFRQ or OPR_FRG output. If the frequency gradi-
ent restores before the module operates, the reset timer is
activated. If the timer reaches the value set by the
Reset
delay Tm df/dt
setting, the operate timer resets and the
STR_FRG output is deactivated. If the frequency restores
before the module operates, the reset timer is activated. If
the timer reaches the value set by the
Reset delay Tm Freq
setting, the operate timer resets and the STR_UFRQ output
is deactivated.
The module calculates the start duration value which indicates the percentage ratio
of the start situation and set operate time (DT). The start duration is available
according to the selected value of the
Operation mode
setting.
Table 663: Start duration value
Operation mode in use
Available start duration value
Freq<
ST_DUR_UFRQ
Freq>
ST_DUR_OFRQ
df/dt
ST_DUR_FRG
The combined start duration START_DUR indicates the maximum percentage ratio
of the active protection modes. The values are available via the Monitored data
view.
1MRS757644 H
Protection functions
620 series
Technical Manual
705
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