YOKOGAWA WT500 User Manual page 192

6.8 Displaying Vectors
Vector Display Examples
When Displaying Numeric Data
(of the sizes of the signals and the phase differences between signals)
For a 3P4W
(three-phase, four-wire system)
• U1(1), U2(1), and U3(1) are
line voltages.
• I1(1), I2(1), and I3(1) are
line currents.
I1(1)
U1(1)
φ1(1),
φU1-I1
I3(1)
φU1-I3
φ3(1)
U3(1)
φU1-U3
When the vector size is zoomed
Example in which the voltage is zoomed
by a factor of 2 and the current by a factor of 1/2
6-22
For a 3P3W system with
a three-voltage, three-current method
• U1(1), U2(1), and U3(1) are
line voltages.
• I1(1), I2(1), and I3(1) are line
currents.
Size of the peripheral circle (range)
φU1-U2
φU1-I2
φU1-U2
I3(1)
U2(1)
φ2(1)
I2(1)
• By moving the vectors U1(1), U2(1), and
U3(1) so that the starting points of all
I1(1)
vectors are at the origin O, the phase
relationship can be observed in the same
fashion as the 3P4W system. For
information about the relationship between
φU3-U1
the positions of the vectors after they have
U1(1)
been moved, see "Vector Display of
U3(1)
Harmonic Data" in section 7.1. (The WT500
O
does not provide a function for moving the
vectors.)
U2(1)
• The phase difference between the line
φU2-U3
voltages can be determined from the phase
difference measurement functions φU1 - U2
I2(1)
and φU1-U3.
φU1 - U2 = Measurement function φU1 - U2
φU2 - U3 = (φU1-U3) – (φU1 - U2) – 180
φU3 - U1 = – (φU1-U3)
The value of the size of the peripheral circle
(range)
The sizes of the vectors representing
voltage and current are multiplied 2 times
and 1/2 times, respectively.
For a 3P3W
(three-phase, three-wire system)
• U1(1), U2(1), and U3(1) are line
voltages.
• I1(1), I2(1), and I3(1) are line
currents.
However, U3(1) and I3(1) are not
actually
measured for the 3P3W system.
The vectors
are displayed through computation.
IM 760201-01E