User's Manual

Appendices
Measuring Methods A
A-5
VA fund - Fundamental Apparent Power (S)
Fundamental apparent phase power:
X1X1X1
IUS
⋅
=
Fundamental apparent system power Υ:
+++
⋅⋅=
111Y
IU3S
Apparent system power is NOT the sum of the phase powers!
Fundamental apparent system power Δ:
+++
Δ
⋅⋅=
111
IU3S
var –Fundamental Reactive Power (Q)
For reactive power only the fundamental power is of interest.
Fundamental reactive phase power:
(
)
X1X1X1X1X1
iusinIUQ ϕ−ϕ
⋅
⋅
=
Fundamental reactive system power Υ and Δ:
(
)
+++++
ϕ−ϕ⋅⋅=
11111
iusinIU3Q
System reactive power is NOT the sum of the phase powers!
VA Harmonics Power (Dh)
Harmonics powers are calculated using the full apparent power S
X
and the fundamental
apparent power S
1X
.
Harmonic distortion power:
2
X1
2
XX
SSDh −=
Harmonic distortion system power Υ and Δ:
2
1
2
SSDh −=
Harmonic distortion system power is NOT the sum of the phase powers!
VA Unbalance Power (Du)
Unbalance powers cannot be measured per phase. Unbalance is only measured on system
level.
Unbalance is calculated from the fundamental system apparent power and the positive
sequence component of the system apparent power.
Unbalance system power Υ and Δ:
2
1
2
1
SSDu
+
−=
Power Factor (PF)
Power Factor indicates system effectiveness at full bandwidth and is calculated from full
spectrum power (up to 50
th
harmonic) and apparent power.
Power factor:
XXX
SPPF
=
System power factor Υ and Δ:
SPPF
=