Operation mode
Description
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. 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
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_OFRQ 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.
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 423: Start duration value
Operation mode in use
Available start duration value
Freq<
ST_DUR_UFRQ
Freq>
ST_DUR_OFRQ
df/dt
ST_DUR_FRG
The combined start duration START_DUR indicates the maximum percentage ratio
of the active protection modes. The values are available via the Monitored data view.
Blocking logic
There are three operation modes in the blocking functionality. The operation modes
are controlled by the BLOCK input and the global setting "Configuration/System/
Blocking mode" which selects the blocking mode. The BLOCK input can be
controlled by a binary input, a horizontal communication input or an internal signal
of the IED program. The influence of the BLOCK signal activation is preselected
with the global setting Blocking mode.
The Blocking mode setting has three blocking methods. In the "Freeze timers"
mode, the operation timer is frozen to the prevailing value. In the "Block all"
mode, the whole function is blocked and the timers are reset. In the "Block
OPERATE output" mode, the function operates normally but the OPERATE output
is not activated.
1YHT530004D05 D Section 4
Protection functions
615 series 499
Technical Manual
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