40
DMC3S - Manual - 08 - 2021
—
Maximum directional active power - 32P
Measurement criterion
The protection calculates the active power
P
using the formula:
P
=
U
L1
I
L1
cos
f
L1
+
U
L2
I
L2
cos
f
L2
+
U
L3
I
L3
cos
f
L3
where
U
L1
,
U
L2
,
U
L3
are the fundamental components of the three phase voltages measured by the
TVs on the generator side,
I
L1
,
I
L2
,
I
L3
are the fundamental components of the three phase currents,
cos
f
L1
, cos
f
L2
, cos
f
L3
are the power factors of the three phases and
f
L1
,
f
L2
,
f
L3
, are the phase shifts
of the phase currents
I
L1
,
I
L2
,
I
L3
relative to the phase voltages
U
L1
,
U
L2
,
U
L3
respectively, considered
conventionally positive with the currents delayed relative to the voltages.
If the current
I
L2
is not available, it is reconstructed vectorially.
For the active power sign conventions, refer to the insertion diagram.
Regulations
The protection is enabled at start and trip according to the trip direction settings, which are pro-
grammed independently for the two thresholds.
Trip direction setting:
Direct
(Forward):
Trip direction setting:
Inverse
(Reverse):
Trip direction setting: Direct/
Inverse
(Forward/Reverse):
P
Q
Trip characteristic of the threshold P1> of the Directional active overpower function (32P)
Trip direction setting: P Positive
TRIP
P1>
P
Q
Trip characteristic of the threshold P1> of the Directional active overpower function (32P)
Trip direction setting: P Negative
TRIP
P1>
P
Q
Trip characteristic of the threshold P1> of the Directional active overpower function (32P)
Trip direction setting: P Positive/Negative
TRIP
P1>
TRIP
P1>
