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App.4-2
IM CW240E
When using the reactive power method
The harmonic power phase angle equations is
Pn
Qn
pn
= tan
–1
(
)
θ
and Pn (active power) and Qn (reactive power) both have polarity. As a result,
φ
pn becomes 0 to ±180°, and the inflow/outflow and lead/lag of harmonics can
be determined, as indicated below.
• When –90 to 90° : Harmonics are
flowing from the power supply to the
load
.
• When –90 to –180° or 90 to 180°
: Harmonics are
flowing from the load to the power
supply
.
• When 0 to 180° : Lead phase
• When 0 to –180° : Lag phase
Appendix 4 Polarity (Harmonic Measurement)