YOKOGAWA CW240

App.4-1
IM CW240E
Appendix
App
Appendix 4 Polarity
(Harmonic Measurement)
● Voltage Phase Angle, Current Phase Angle
With the CW240, measurement can be done selecting either the U1
fundamental wave phase or the measurement element fundamental wave
phase as the standard.
In either case, the polarity is as follows.
• Lead : + (0 to 180°)
• Lag : – (0 to -180°)
● Harmonic Power
Harmonic power measures the electric power of each order. The following is
determined according to polarity.
• When the polarity of harmonic power is +: Harmonics are flowing from
the power supply to the load.
• When the polarity of harmonic power is –: Harmonics are flowing from
the load to the power supply.
● Harmonic Power Phase Angle
The harmonic power phase angle calculates the phase angle from the power
factor of each order.
There is a difference between using the reactive power method and not using it,
as indicated below.
When not using the reactive power method
The harmonic power phase angle formula is
pn = cos
–1
( )
Sn
Pn
θ
and Pn (active power) has polarity, but Sn (apparent power) does not have
polarity. As a result, φpn becomes 0 to 180°, and the inflow/outflow of harmonics
can be determined as indicated below, but lead/lag cannot be determined.
• When 0 to 90° : Harmonics are flowing from the power supply to the
load.
• When 90 to 180° : Harmonics are flowing from the load to the power
supply.