Operation mode
Description
df/dt The function operates independently as the frequency gra-
dient ("df/dt"), rate-of-change, protection function. When
the frequency gradient exceeds the set value of the
Start
value df/dt
setting, the module activates the START and
STR_FRG outputs. The time characteristic is according to
DT. When the operation timer has reached the value set by
the
Operate Tm df/dt
setting, the OPERATE and OPR_FRG
outputs are activated. If the frequency gradient restores be-
fore the module operates, the reset timer is activated. If the
timer reaches the value set by the
Reset delay Tm df/dt
set-
ting, the operate timer resets and the START and STR_FRG
outputs are deactivated.
Freq< + df/dt A consecutive operation is enabled between the protection
methods. When the measured frequency is below the set
value of the
Start value Freq<
setting, the frequency gradi-
ent protection is enabled. After the frequency has dropped
below the set value, the frequency gradient is compared to
the set value of the
Start value df/dt
setting. When the fre-
quency gradient exceeds the set value, the module activates
the START and STR_FRG outputs. The time characteristic is
according to DT. When the operation timer has reached the
value set by the
Operate Tm df/dt
setting, the OPERATE and
OPR_FRG outputs are activated. If the frequency gradient
restores before the module operates, the reset timer is acti-
vated. If the timer reaches the value set by the
Reset delay
Tm df/dt
setting, the operate timer resets and the START
and STR_FRG outputs are deactivated. The OPR_UFRQ out-
put is not active when this operation mode is used.
Freq> + df/dt A consecutive operation is enabled between the protection
methods. When the measured frequency exceeds the set val-
ue of the
Start value Freq>
setting, the frequency gradient
protection is enabled. After the frequency exceeds the set
value, the frequency gradient is compared to the set value of
the
Start value df/dt
setting. When the frequency gradient
exceeds the set value, the module activates the START and
STR_FRG outputs. The time characteristic is according to
DT. When the operation timer has reached the value set by
the
Operate Tm df/dt
setting, the OPERATE and OPR_FRG
outputs are activated. If the frequency gradient restores be-
fore the module operates, the reset timer is activated. If the
timer reaches the value set by the
Reset delay Tm df/dt
set-
ting, the operate timer resets and the START and STR_FRG
outputs are deactivated. The OPR_OFRQ output is not active
when this operation mode is used.
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 availa-
ble at the STR_UFRQ and STR_FRG outputs. The shortest
operate delay time from the set
Operate Tm Freq
or
Oper-
Table continues on the next page
1MRS758755 C Protection functions
REC615 & RER615
Technical Manual
451
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