GE 469 Instruction Manual page 273

CHAPTER 6: ACTUAL VALUES
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL
When the relay set for the "Wye" VT connection type, voltages are measured at terminals
G2 (V ), H1 (V ), and H2 (V
A B C
The phase-to-phase voltages are calculated using the following relationships:
Vab = 3 × VA
× VB
Vbc = 3
Vca = 3 × VC
The quantities displayed by the relay and the EnerVista 469 Setup software are
straightforward and follow the phasor diagram shown below. Note that all the angles
shown are negative or lagging angles.
Vca
806557A1.CDR
FIGURE 6–9: Typical Phasor Diagram for Wye Connection
Using the same example as for the open delta connection, except for the
setting to "Wye", the following quantities are displayed by the relay and EnerVista 469
TYPE
Setup software:
In the
A2 METERING DATA
: "4025 Volts"
VAB
: "4025 Volts"
VBC
: "4025 Volts"
VCA
AVERAGE LINE VOLTAGE
: "2323 Volts"
VAN
) with respect to G1 (V ). Refer to the figure below for details.
COM
FIGURE 6–8: Wye VT Connection
Phase Rotation
Vcn
Vab
Van
Vbn
Vbc
menu:
VOLTAGE METERING
: "4025 Volts"
806562A1.CDR
System Voltages:
Van; Vab
Vbn; Vbc
Vcn; Vca
Measured Voltages
VA (G2 – G1)
VB (H1 – G1)
VC (H2 – G1)
Calculated Voltages
= ×
Vab 3 VA
= ×
Vbc 3 VB
= ×
Vca 3 VC
Displayed Voltages:
Van = VA
Vbn = VB
Vcn = VC
Vab = As Calculated
Vbc = As Calculated
Vca = As Calculated
VT CONNECTION
6–23