VAMP 50 User Manual

4.9 Direction of power and current 4 Measurement functions Technical description
144
VAMP 24h support phone +358 (0)20 753 3264 VM50.EN004
Active, reactive and apparent power are calculated as follows:
S
P
QPS
QQ
PP
L
L




 cos
3
3
22
1
1
4.9. Direction of power and current
Figure 4.9-1 shows the concept of three phase current direction
and sign of cos
 and power factor PF. Figure 4.9-2 shows the
same concepts, but on a PQ-power plane.
I
V
REF
+ind
Forward inductive power
current is lagging
cos = +
PF = +

+cap
Forward capacitive power
current is leading
cos = +
PF =




ind
Reverse inductive power
current is leading
cos =
PF = +



cap
Reverse capacitive power
current is lagging
cos =
PF =
0°
+90°
UI_Quadrants
Figure 4.9-1 Quadrants of voltage/current phasor plane
S
P
Q
+ind
Forward inductive power
current is lagging
cos = +
PF = +

+cap
Forward capacitive power
current is leading
cos = +
PF =




ind
Reverse inductive power
current is leading
cos =
PF = +



cap
Reverse capacitive power
current is lagging
cos =
PF =
0°
+90°
PQ_Quadrants
Figure 4.9-2 Quadrants of power plane

VAMP 50 Specifications

General

Brand	VAMP
Model	50
Category	Relays
Language	English