ABB RELION REX640 Technical Manual page 978

Section 4
Protection functions
972
under excitation
Operating area
Pwr sector
Min reactive power
reduction
-P
GUID-D101380B-3794-446D-9501-9AA42FCD308D V1 EN
Figure 527: 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
The power direction can be reversed by setting Pol reversal to "True".
Timer
Once activated by both Under voltage detection and Reactive power monitoring
module, Timer activates the START output. The Timer characteristic is according to
DT. When the operation timer has reached the value set by Operate delay time, the
OPERATE output is activated. If the fault disappears before the module operates, the
Timer is reset instantaneously.
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
by a binary input, a horizontal communication input or an internal signal of the
protection relay's program. The influence of the BLOCK signal activation is
preselected with the global setting Blocking mode.
+Q
Generator
under excitation
II
Min Ps Seq current
-Q
III
1MRS759142 C
Motor
I
Operating area
Pwr sector
reduction
IV
Technical Manual
+P
REX640