Line Vt Sensing; Power System; Flexcurves - GE 750 Instruction Manual

750/760
Feeder Management Relay

Line VT Sensing

LINE VT
SENSING

Power System

POWER SYSTEM

FlexCurves™

FLEXCURVE A
5–18
PATH: SETPOINTS S2 SYSTEM SETUP
[ ] VT CONNECTION TYPE:
Vbn
NOMINAL VT SECONDARY
MESSAGE
VOLTAGE: 120.0 V
VT RATIO:
MESSAGE
120.0:1
With a Line VT installed, the relay can be used to check for a condition of
synchronism between two voltages, either line-line or line-neutral.
• VT CONNECTION: Enter the Line VT connection made to the system. This
selection is critical to the operation of synchrocheck, as it instructs the relay
which Bus VT input voltage is to be compared to the Line VT input voltage. See
FIGURE 3–15: Line VT Connections on page 3–11 for the system connection to
match this setpoint.
• NOMINAL VT SECONDARY VOLTAGE: This setpoint represents the voltage
across the VT secondary winding when nominal voltage is applied to the
primary. On a source of 13.8 kV line-line at nominal voltage, with a
14400:120 V VT in the Delta connection, the voltage to be entered is 115 V. For
the Wye connection, the voltage to be entered is 115 /
• VT RATIO: Enter the VT primary to secondary turns ratio with this setpoint. For
a 14400:120 VT, the entry would be "120:1" (since 14400 / 120 = 120.0).
PATH: SETPOINTS S2 SYSTEM SETUP
[ ] NOMINAL FREQ:
60 Hz
PHASE SEQUENCE:
MESSAGE
ABC
COST OF ENERGY:
MESSAGE
5.0 ¢/kWh
The power system data is entered in this setpoint subgroup.
• NOMINAL FREQ: Enter the nominal power system frequency. This value is
used as a default to set the optimal digital sampling rate if the system
frequency cannot be measured as there is no voltage available at the bus
voltage phase A input terminals.
• PHASE SEQUENCE: Enter the phase sequence of the power system.
• COST OF ENERGY: Kilowatt hour power usage is converted to a cost of energy
using this setpoint. The cost of energy charged by a utility is usually a variable
rate depending on total energy consumed or other factors. Enter an estimated
average cost in cents per kWh. Approximate energy cost will be determined by
the relay, providing a value useful for budgeting purposes.
PATH: SETPOINTS S2 SYSTEM SETUP
[ ] CURVE TRIP TIME AT
1.03 x PU:
CURVE TRIP TIME AT
MESSAGE
1.05 x PU:
CURVE TRIP TIME AT
MESSAGE
20.0 x PU:
http://www.GEmultilin.com
LINE VT SENSING
Range: Van, Vbn, Vcn, Vab, Vcb
Range: 50.0 to 240.0 V in steps of 0.1
Range: 1.0 to 5000.0 in steps of 0.1
3
= 66.4 V.
POWER SYSTEM
Range: 25 to 60 Hz in steps of 1
Range: ABC, ACB
Range: 1.0 to 25.0 ¢/kWh in steps of 0.1
FLEXCURVE A(B)
Range: 0 to 65535 ms in steps of 1
0 ms
Range: 0 to 65535 ms in steps of 1
0 ms
↓
Range: 0 to 65535 ms in steps of 1
0 ms
S2 System Setup
GE Multilin