User`s guide

B-5
APPENDIX B/ Technical Specifications
Computed Parameters
Single Channel
Parameters
The computations below apply to single channel parameters.
Note that 0
V
= Phase Angle of Voltage, while 0
I
= Phase Angle of Current.
True Average
Power
Average of the instantaneous power samples taken as the product of voltage and
current samples. Includes sign to indicate direction of power flow: positive (+) from
source to load, negative (-) from load to source.
where N = number of samples
Vn = Voltage at sample n
In = Current at sample n
Apparent Power
Unsigned value calculated using the product of the rms values of the voltage and
current.
Fundamental
Apparent Power
Unsigned value calculated using the product of the fundamental rms values of the
voltage and current.
Fundamental
Power
Signed value calculated using the product of the fundamental apparent power and the
cosine of the phase angle between the fundamental frequency components of voltage
with respect to current (0 = 0
V
- 0
I
).
Volt Ampere
Reactive
Signed value calculated using the product of the fundamental apparent power and the
sine of the phase angle between the fundamental frequency components of voltage with
respect to current (0 = 0
V
- 0
I
).
Continued on next page
I
ABC
I
A
I
B
I
C
++=
RMSRMS
I
V
VA
=
fundfundfund
IVVA
=
∑
=
=
N
n
nn
IV
N
WATT
1
1
θ
sin
fundfund
VAVAR
=
θcos
fundfund
VAWATT =