Hioki CM3286 - Equations; Power Measurement Formulas

87
Equations
Equations
(1) Single-phase power measurement
Apparent power
S U
RMS
・
I
RMS
• The active power
P
has no sign during
consumption and a negative sign during
generation.
• Due to the effects of measurement error
,
S
=|
P
| and
Q
=0 are used when
S
<|
P
|.
Reactive power
Q
22
PS −
Power factor
PF
S
P
(2) Balanced 3-phase/3-wire power measurement
Balanced 3-phase/3-wire
zero-cross phase angle
φ
(3P3W)
φ
−30°
• The symbol
φ
represents the zero-
cross phase angle of the voltage
U
12
and the current
I
1
.
• The symbol
S
represents the
apparent power of the line voltage
U
12
and the wire current
I
1
.
Balanced 3-phase/3-wire
power factor
PF
(3P3W)
{ }
)33(
cos
WP
φ
Balanced 3-phase/3-wire
active power
P
(3P3W)
[W]
S
WP
⋅⋅
)33(
3
PF
Balanced 3-phase/3-wire
apparent power
S
(3P3W)
[VA]
S⋅3
Balanced 3-phase/3-wire
reactive power
Q
(3P3W)
[var]
2
)33(
2
)33( WPWP
PS −