ABB RELION REX640 Technical Manual page 985

1MRS759142 C
REX640
Technical Manual
Generator convention
Forward reactive power
+Q
Synchronous
Generator
motor
PF<0 (lead) PF>0 (lag)
Q2 Q1
(PF = -1.0)
Q3 Q4
-P
PF<0 (lag)
PF>0 (lead)
Induction Induction
motor generator
-Q
Reverse reactive power
I
E
GUID-DDD24761-64AE-4FCE-9473-7FF6061C2943 V1 EN
Figure 531: Power factor quadrant
If the polarity of the voltage signal is opposite to the normal polarity, the correction
can be done by setting Voltage reversal to "Yes", which rotates the power factor
vector by 180 degrees.
If the magnitude of all three phase currents or voltages are respectively less than
Current block value and Voltage block value settings, the power factor is set as unity
that is 1.00 and the function is disabled internally.
The DISABLE input can be used to coordinate the correct operation during the start-
up situation. By activating the DISABLE signal, the power factor calculation is
blocked. Once the DISABLE signal is deactivated, the function remains blocked for
additional time duration as set through the setting Disable time.
Level detector 1
The Level detector 1 compares the calculated power factor to the set Start value. If the
power factor value goes below the set Start value in the direction as defined by Dir
start value, the Level detector sends an enabling signal to the Timer 1 module.
Level detector 2
The Level detector 2 compares the calculated power factor to the set Alarm value. If
the power factor value goes below the set Alarm value in the direction as defined by
Dir alarm value, the Level detector sends an enabling signal to the Timer 2 module.
Timer 1
Once activated, the Timer 1 activates the START output. The timer characteristic is
according to DT. When the operate timer has reached the value set by Start delay time
(PF = -1.0)
(PF = 1.0)
+P -P
V
Section 4
Protection functions
Motor convention
Forward reactive power
+Q
Induction Induction
generator motor
PF<0 (lead) PF>0 (lag)
Q2 Q1
(PF = 1.0)
Q3 Q4
PF<0 (lag)
PF>0 (lead)
Synchronous
Generator
motor
-Q
Reverse reactive power
I
E V
+P
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