ABB RELION 620 Series Technical Manual page 327

1MAC504801-IB E
620 series ANSI
Technical Manual
Table 263: Operation modes for operation logic
Operation mode
Freq<
Freq>
df/dt
Table continues on next page
Protection functions
Description
The function trips independently as the
underfrequency ("Freq<") protection function. When
the measured frequency is below the set value of the
Pickup value Freq< setting, the module activates the
PICKUP and PICKUP_UFRQ outputs. The time
characteristic is according to DT. When the operation
timer has reached the value set by the
setting, the TRIP and TRIP_UFRQ outputs are
activated. If the frequency restores before the
module trips, the reset timer is activated. If the timer
Reset delay Tm Freq
reaches the value set by the
setting, the trip timer resets and the PICKUP and
PICKUP_UFRQ outputs are deactivated.
The function trips independently as the
overfrequency ("Freq>") protection function. When
the measured frequency exceeds the set value of the
Pickup value Freq> setting, the module activates the
PICKUP and PICKUP_OFRQ outputs. The time
characteristic is according to DT. When the operation
timer has reached the value set by the
setting, the TRIP and TRIP_OFRQ outputs are
activated. If the frequency restores before the
module trips, the reset timer is activated. If the timer
Reset delay Tm Freq
reaches the value set by the
setting, the trip timer resets and the PICKUP and
PICKUP_OFRQ outputs are deactivated.
The function trips independently as the frequency
gradient ("df/dt"), rate-of-change, protection
function. When the frequency gradient exceeds the
Pickup value df/dt setting, the module
set value of the
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
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
Tm df/dt setting, the trip timer resets and the PICKUP
and PICKUP_FRG outputs are deactivated.
Section 4
Trip Tm Freq
Trip Tm Freq
Trip
Reset delay
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