GE Multilin 469 Instruction Manual page 270

6–20
The following phasor diagram presents, in graphic form, the relationship between system
quantities and how they are measured, calculated, and displayed. Note that all angles
shown are negative or lagging angles.
Phase Rotation
Vca
Vbc
FIGURE 6–6: Typical Phasor Diagram for Open Delta Connection
For example, assume a balanced three phase system with a VT Turn Ratio of 35:1, VT
ratings 4200/120 V, and motor running at full load with a power factor of 0.95 (18.2° angle).
When the measured phase to phase voltage is 115 V, the following quantities are displayed
by the relay and EnerVista 469 Setup software:
In the
A2 METERING DATA
: "4025 Volts"
VAB
: "4025 Volts"
VBC
: "4025 Volts"
VCA
AVERAGE LINE VOLTAGE
: "60.00 Hz"
SYSTEM FREQUENCY
In the
A2 METERING DATA
: "95.8% at 0° Lag"
VA PHASOR
: "0.0% at 48° Lag"
VB PHASOR
: "95.8% at 300° Lag"
VC PHASOR
: "100.0% at 48° Lag"
IA PHASOR
: "100.0% at 168° Lag"
IB PHASOR
: "100.0% at 288° Lag"
IC PHASOR
The EnerVista 469 Setup software displays the following screen for
values:
PHASORS
VC = –Vbc
VA = Vab
Vac
menu:
VOLTAGE METERING
: "4025 Volts"
menu:
PHASORS
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 6: ACTUAL VALUES
System Voltages:
Vab
Vbc
Vca
Measured Voltages:
Vab = VA (G2 – G1)
–Vbc = VC (H2 – G1)
Calculated Voltage:
Vac = Vab + Vbc
Displayed Voltages:
Va = Vab
Vb = 0°
Vc = –Vbc
806556A1.CDR
A2 METERING DATA