If all three phase voltages and phase currents are fed to the protection
relay, the positive-sequence alternative is recommended (default).
Depending on the set
Measurement mode
, the power calculation calculates active
power, reactive power and apparent power values from the available set of
measurements. The calculated powers S, P, Q and the power factor angle, PF_ANGL,
are available in the Monitored data.
Directional calculation
The Directional calculation determines the direction of the measured power. The
measured power is considered to be in the forward direction if the active power is
positive, else it is considered to be in the reverse direction.
If the polarity of the measured power is opposite to normal, the correction can be
done by setting
Pol reversal
to "True", which rotates the apparent power by 180
degrees.
Level detector
The Level detector compares the calculated value of the active power with a set
Start value
. If the calculated value of the active power falls below
Start value
in the
forward direction or if the measured power is in the reverse direction, the Level
detector enables the Timer module.
P
Q
Non
operating
area
Operating
area
Start Value
Figure 380: Operating characteristics of DUPPDPR with setting Start value
Timer
Once activated, the Timer activates the START output. The time characteristics
are according to DT. When the operation timer has reached the value of
Operate
1MRS757644 H
Protection functions
620 series
Technical Manual
731
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