Operation mode
Description
Freq> + df/dt A consecutive operation is enabled between the protection methods.
When the measured frequency exceeds the set value of the
Pickup
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
Pickup value df/dt
setting. When the
frequency gradient exceeds the set value, the module activates the
PICKUP and PICKUP_FRG outputs. The time characteristic is
according to DT. When the operation timer has reached the value set by
the
Trip Tm df/dt
setting, the TRIP and TRIP_FRG outputs are
activated. If the frequency gradient restores before the module trips, the
reset timer is activated. If the timer reaches the value set by the
Reset
delay Tm df/dt
setting, the operation timer resets and the PICKUP and
PICKUP_FRG outputs are deactivated. The TRIP_OFRQ output is not
active when this operation mode is used.
Freq< OR df/dt A parallel operation between the protection methods is enabled. The
PICKUP output is activated when either of the measured values of the
protection module exceeds its set value. Detailed information about the
active module is available at the PICKUP_UFRQ and PICKUP_FRG
outputs. The shortest trip delay time from the set
Trip Tm Freq
or
Trip
Tm df/dt
is dominant regarding the TRIP output. The time characteristic
is according to DT. The characteristic that activates the TRIP output
can be seen from the TRIP_UFRQ or TRIP_FRG output. If the frequency
gradient restores before the module trips, the reset timer is activated. If
the timer reaches the value set by the
Reset delay Tm df/dt
setting, the
operation timer resets and the PICKUP_FRG output is deactivated. If
the frequency restores before the module trips, the reset timer is
activated. If the timer reaches the value set by the
Reset delay Tm Freq
setting, the operation timer resets and the PICKUP_UFRQ output is
deactivated.
Freq> OR df/dt A parallel operation between the protection methods is enabled. The
PICKUP output is activated when either of the measured values of the
protection module exceeds its set value. Detailed information about the
active module is available at the PICKUP_OFRQ and PICKUP_FRG
outputs. The shortest trip delay time from the set
Trip Tm Freq
or
Trip
Tm df/dt
is dominant regarding the TRIP output. The time characteristic
is according to DT. The characteristic that activates the TRIP output
can be seen from the TRIP_OFRQ or TRIP_FRG output. If the frequency
gradient restores before the module trips, the reset timer is activated. If
the timer reaches the value set by the
Reset delay Tm df/dt
setting, the
operation timer resets and the PICKUP_FRG output is deactivated. If
the frequency restores before the module trips, the reset timer is
activated. If the timer reaches the value set by the
Reset delay Tm Freq
setting, the operation timer resets and the PICKUP_UFRQ output is
deactivated.
The module calculates the pickup duration value PICKUP_DUR which indicates the
percentage ratio of the pickup situation and set trip time DT. The pickup duration is
available according to the selected value of the Operation mode setting.
1MAC059074-MB A Section 4
Protection functions
615 series ANSI 681
Technical Manual
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