PSM1700 PsimetriQ user manual
13-2
When the integrator function is activated, the following
values are available:
Elapsed time (in hours, minutes and seconds)
Watt-hours (true and fundamental)
VA hours (true and fundamental)
average power factor (true and fundamental)
Ampere hours (true and fundamental)
The power dissipated in a load subjected to a periodic
voltage, v(), with a current flowing a(), is given by:
2
w = 1/2
v().a() d
0
For a sampled signal, the formula becomes:
i = n-1
w = 1/n
v[i].a[i]
i = 0
where n is the number of samples for an integral number
of complete cycles of the input waveform.
These are elementary definitions that are valid for all
waveshapes. PsimetriQ computes the true watts value
from the elementary definition for sampled data. Formulae
for the components at the fundamental frequency are
given in the section on frequency response analysis;
formulae for the harmonic components are given in the
section on harmonic analysis.
The formulae for the derived results are:
VA = V
rms
x A
rms
power factor = Watts/VA
fundamental Watts = V
real
x A
real
+ V
quad
x A
quad