PPA5xx/15xx user manual
12-3
than TDD unless the measured rms current is greater than
the entered rated current.
The value for TRD and TDD will always be lower than the
computed THD as rms is always greater than the
fundamental.
i = n
TDD = 1/rms √
h
i
²
i = 2
where h
i
is the i
th
harmonic
Harmonic phase can be selected instead of a thd
computation and each harmonic in the series is computed
as a magnitude and phase angle.
The number of harmonics used for THF, TIF, TRD, TDD and
series harmonic phase computation is selectable in the
same way as for THD.
In all cases, the harmonics are phase referred to Phase 1
voltage fundamental so that their in-phase and quadrature
components may be separately filtered to minimise noise.
Accurate frequency synchronisation is essential for reliable
harmonic measurement. Good results can be obtained in a
reasonable time using the medium speed setting (which
runs a little slower than other modes) but for the best
results, use the slow speed setting.
To Next Page
Loading...
Need help?
General
