GE Grid Solutions Multilin 9450 Instruction Manual page 10

WYE CONNECTION
1–2
Phase 2
V
B
Figure 1-1: Three-phase Wye Winding
The three voltages are separated by 120
the currents are also separated by 120
conditions can cause the currents to depart from the ideal 120
phase voltages and currents are usually represented with a phasor diagram. A phasor
diagram for the typical connected voltages and currents is shown in Figure 1.2.
V
B
Figure 1-2: Phasor Diagram Showing Three-phase Voltages and Currents
The phasor diagram shows the 120
The phase-to-phase voltage in a balanced three-phase wye system is 1.732 times the
phase-to-neutral voltage. The center point of the wye is tied together and is typically
grounded. Table 1.1 shows the common voltages used in the United States for wye-
connected systems.
Table 1.1: Common Phase Voltages on Wye Services
Phase to Ground Voltage
120 volts
277 volts
2,400 volts
7,200 volts
EPM 9450/9650 ADVANCED POWER QUALITY METERING SYSTEM – INSTRUCTION MANUAL
CHAPTER 1: THREE-PHASE POWER MEASUREMENT
V
C
Phase 3
N
Phase 1
o
electrically. Under balanced load conditions
o
. However, unbalanced loads and other
V
C
I
C
N
I
B
o
angular separation between the phase voltages.
Phase to Phase Voltage
208 volts
480 volts
4,160 volts
12,470 volts
V
A
o
separation. Three-
I
A
V
A