Hioki PW3360-20, Инструкция по эксплуатации, Страница: 214 / 224

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Differences in 3-phase/3-wire/3-wattmeter measurement (3P3W3M) calcu-
lations between the PW3360 and the 3169-20/21
This section describes differences in how the PW3660 Clamp on Power Logger and
the 3169-20/21 Clamp on Power HiTester perform calculations during 3-phase/3-
wire/3-wattmeter (3P3W3M) measurement.
As indicated in the following table, the apparent power and power factor values gen-
erated by the 3169-20/21 for each channel are not available for each phase because
the instrument uses line-to-line voltages to calculate apparent power and power fac-
tor for each channel. By contrast, since the PW3660 uses phase voltages, the
apparent power and power factor values for each channel are available for each
phase. Consequently, it is possible to check balance for individual phases.
Item
Model PW3360(3P3W3M)
When the PF/Q/S calculation
selection is set to RMS (p.64)
Relative
merits
Model 3169-20/21(3P3W3M)
The reactive power meter
method is not used.
Voltage
U1
= -
=
= -
U2
= - = -
U3
= - = -
Current
I1 =
I2
I3
Active
power
P1 =
P2
P3
P P1+P2+P3 P1+P2+P3
Apparent
power
S1 u
1
I
1
Since calculations are
based on the phase
voltage and phase
(line) current, it is
possible to check the
apparent power for
each of the three
phases.
> U
1
I
1 Since calculations are
based on the line-to-
line voltage and line
(phase) current,
apparent power val-
ues are not generated
for individual phases.
S2 u
2
I
2
U
2
I
2
S3
u
3
I
3
U
3
I
3
S
(U1I1+U2I2+U3I3)
=
(U1I1+U2I2+U3I3)
Power factor
si: Indicates
lag/lead.
PF1
si
Since calculations are
based on the phase
voltage and phase
(line) current, it is
possible to check the
power factor for indi-
vidual phases.
>
si
Since calculations are
based on the line-to-
line voltage and
phase (line) current,
power factor values
are not generated for
individual phases.
PF2
si
si
PF3
si si
PF
si
=
si
U
1
u
1
u
2
U
1
u
1
u
2
U
2
u
2
u
3
U
2
u
2
u
3
U
3
u
3
u
1
U
3
u
3
u
1
I
1
I
1
I
2
I
2
I
3
I
3
u
1
I
1
u
1
I
1
u
2
I
2
u
2
I
2
u
3
I
3
u
3
I
3
3
3
3
3
1 1
I u
P1
1 1
I U
P1
2 2
I u
P2
2 2
I U
P2
3 3
I u
P3
3 3
I U
P3
S
P
S
P