ABB RER620

1MAC309294-MB F Section 4
Protection functions
RER620 219
Technical Manual
Table 234: Operation modes for operation logic
Operation mode Description
Freq< The function operates independently as the underfrequency (“Freq<“) protection
function. When the measured frequency is below the set value of the
Start value Freq<
setting, the module activates the START and STR_UFRQ outputs. The time
characteristic is according to DT. When the operation timer has reached the value set
by the
Operate Tm Freq setting, the OPERATE and OPR_UFRQ outputs are activated. 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 START and STR_UFRQ outputs are deactivated.
Freq> The function operates independently as the overfrequency (“Freq>”) protection
function. When the measured frequency exceeds the set value of the
Start value Freq>
setting, the module activates the START and STR_OFRQ outputs. The time
characteristic is according to DT. When the operation timer has reached the value set
by the
Operate Tm Freq setting, the OPERATE and OPR_OFRQ outputs are activated. 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 START and STR_OFRQ outputs are deactivated.
df/dt The function operates independently as the frequency gradient (“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 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 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 gradient 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 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 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 START and STR_FRG
outputs are deactivated. The OPR_UFRQ output 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 value 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 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 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 enabled. 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 available at the STR_UFRQ and
STR_FRG outputs. The shortest operate delay time from the set
Operate Tm Freq or
Operate Tm df/dt is dominant regarding the OPERATE output. The time characteristic is
according to DT. The characteristic that activates the OPERATE output can be seen
from the OPR_UFRQ or OPR_FRG output. If the frequency gradient 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.