ABB RELION 620 Series Technical Manual page 709

1MRS757644 F
620 series
Technical Manual
Operation mode
Freq> + df/dt
Freq< OR df/dt
Freq> OR df/dt
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
Freq<
Freq>
df/dt
Description
A consecutive operation is enabled between the protection
methods. When the measured frequency exceeds the set value of
Start value Freq> setting, the frequency gradient protection is
the
enabled. After the frequency exceeds the set value, the frequency
gradient is compared to the set value of the
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
Operate Tm df/dt setting, the OPERATE and OPR_FRG
set by the
outputs are activated. If the frequency gradient restores before the
module operates, the reset timer is activated. If the timer reaches the
Reset delay Tm df/dt setting, the operate timer
value set by the
resets and the START and STR_FRG outputs are deactivated. The
OPR_OFRQ output is not active when this operation mode is used.
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
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
Reset delay Tm df/dt setting, the operate timer
value set by the
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
the operate timer resets and the STR_UFRQ output is deactivated.
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. A detailed information from
the active module is available at the STR_OFRQ and STR_FRG
outputs. The shortest operate delay time from the set
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_OFRQ
or OPR_FRG output. If the frequency gradient restores before the
module operates, the reset timer is activated. If the timer reaches the
Reset delay Tm df/dt setting, the operate timer
value set by the
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
the operate timer resets and the STR_UFRQ output is deactivated.
Available start duration value
ST_DUR_UFRQ
ST_DUR_OFRQ
ST_DUR_FRG
Section 4
Protection functions
Start value df/dt setting.
Operate Tm
Reset delay Tm Freq setting,
Operate Tm
Reset delay Tm Freq setting,
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