ABB RELION REX640 Technical Manual page 1074

Protection functions
When the reactive power exceeds
area, the module sends an enable signal to the Timer indicating that the reactive
power is being consumed at the grid connection point. A slight tilt in the curve can
be obtained by the setting
To avoid false tripping, reactive power calculation is blocked if the magnitude of
positive sequence current is less than the set
The magnitude of calculated reactive power Q is available in the Monitored data
view.
Figure 600: Operating area of DQPTUV function
Quadrant II Generator produces active power, but draws reactive power (under-excited)
Quadrant III Generator produces both active and reactive power
Timer
Once activated by both Under voltage detection and Reactive power monitoring
module, the Timer activates the START output. The Timer characteristic is according
to DT. When the operation timer has reached the value set by
time , the OPERATE output is activated. If the fault disappears before the module
operates, the Timer is reset instantaneously.
The Timer calculates the start duration value "START_DUR" which indicates the
percentage ratio of the start situation and the set operating time. The value is
available through the Monitored data view.
Blocking logic
There are three operation modes in the blocking function. 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
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Pwr sector reduction .
The power direction can be reversed by setting
Min reactive power and flows in the operating
Min Ps Seq current .
1MRS759142 F
Pol reversal to "True".
Operate delay
REX640
Technical Manual