GE 745 Instruction Manual page 175

CHAPTER 5: SETPOINTS
Note
NOTE
5.6.10.2 Underfrequency

UNDERFREQUENCY []
1
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
We strongly recommend the use of either the voltage, current, or both, signals for
supervision. If no supervising conditions are enabled, the element could produce
undesirable operation!
PATH: SETPOINTS S4 ELEMENTS

UNDERFREQUENCY 1
FUNCTION: Disabled
UNDERFREQUENCY 1
MESSAGE
RLYS (1-8): --------
UNDERFREQUENCY 1
MESSAGE
TARGET: Self-Reset
CURRENT SENSING:
MESSAGE
Enabled
MINIMUM OPERATING
MESSAGE
CURRENT: 0.20 x CT
MINIMUM OPERATING
MESSAGE
VOLTAGE: 0.50 x VT
UNDERFREQUENCY 1
MESSAGE
PICKUP: 59.00 Hz
UNDERFREQUENCY 1
MESSAGE
DELAY: 1.00 s
UNDERFREQUENCY 1
MESSAGE
BLOCK: Disabled
• MINIMUM OPERATING CURRENT: Enter the minimum value of winding 1 phase A
current (in units of relay nominal current) required to allow the underfrequency
element to operate.
• MINIMUM OPERATING VOLTAGE: Enter the minimum value of voltage (in units of relay
nominal voltage) required to allow the underfrequency element to operate.
• UNDERFREQUENCY 1(2) PICKUP: Enter the frequency (in Hz) below which the
underfrequency 1 element will pickup and start the delay timer.
• UNDERFREQUENCY 1(2) DELAY: Enter the time the frequency remains below the
pickup level before element operation.
FREQUENCY UNDERFREQUENCY 1(2)
 
Range:
Range:
Range:
Range:
Range:
Range:
Range:
Range:
Range:
S4 ELEMENTS
Enabled, Disabled
1 to 8
Self-Reset, Latched, None
Enabled, Disabled
0.05 to 1.00 x CT in steps of
0.01
0.10 to 0.99 x CT in steps of
0.01
45.00 to 59.99 Hz in steps of
0.01
0.00 to 600.00 s in steps of 0.01
Logc Inpt 1 to 16, Virt Inpt 1 to
16, Output Rly 2 to 8, SelfTest
Rly, Vir Outpt 1 to 5, Disabled
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