VAMP 50 User Manual

Technical description 4 Measurement functions 4.8 Power calculations
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4.8. Power calculations
NOTE! These calculations is available when voltage measurement mode is 1LL
(line-to-line voltage, see Figure 8.10.2-2) or 1LN (phase-to-neutral
voltage, see Figure 8.10.2-3).
The power calculations in the VAMP 52 are dependant on the
voltage measurement mode. The formulas used by the VAMP
52 for power calculations are found in this chapter
Line to line voltages measured (1LL mode)
As the device is measuring U
12
only, the U
23
voltage is
calculated by assuming that voltages are symmetrical.
1223
2
1201
UaU
a



323112
**
LL
IUIUS 
where,
12
U
= Measured line voltage L1-L2 phasor, fundamental
frequency component.
1
*
L
I
= Complex conjugate of the measured phase L1
current phasor.
23
U
= Measured line voltage L2-L3 phasor, fundamental
frequency component
3
*
L
I
= Complex conjugate of the measured phase L3
current phasor.
S
P
SimagQ
SrealP



 cos
)(
)(
Phase to neutral voltages measured (1LN mode)
Active power calculat
ion for one phase:

cos
111


LLL
IUP
Reactive power calculation for one phase:

sin
111


LLL
IUQ
where,
U
L1
= Measured L1 phase voltage
I
L1
= Measured L1 current

= Angle between U
L1
and I
L1

VAMP 50 Specifications

General

Brand	VAMP
Model	50
Category	Relays
Language	English