GE 745 Instruction Manual page 166

S4 ELEMENTS
5.6.7.2 Ground Time Overcurrent
 
W1 GND [
TIME OC
5–70
PATH: SETPOINTS S4 ELEMENTS

] W1 GROUND TIME OC
FUNCTION: Enabled
W1 GROUND TIME OC
MESSAGE
RLYS (1-8): --------
W1 GROUND TIME OC
MESSAGE
TARGET: Latched
W1 GROUND TIME OC
MESSAGE
PICKUP: 0.85 x CT
W1 GROUND TIME OC
MESSAGE
SHAPE: Ext Inverse
W1 GROUND TIME OC
MESSAGE
MULTIPLIER: 1.00
W1 GROUND TIME OC
MESSAGE
RESET: Linear
W1 GROUND TIME OC
MESSAGE
BLOCK: Disabled
• W1(3) GROUND TIME OC PICKUP: Enter the level of ground current (in units of relay
nominal current) above which the winding 1(3) ground time overcurrent element will
pickup and start timing.
• W1(3) GROUND TIME OC SHAPE: Select the time overcurrent curve shape to be used
for the winding 1(3) ground time overcurrent element. Refer to Time Overcurrent
Curves on page 5–59 for a description of the time overcurrent curve shapes.
• W1(3) GROUND TIME OC MULTIPLIER: Enter the multiplier constant by which the
selected time overcurrent curve shape (the base curve) is to be shifted in time.
• W1(3) GROUND TIME OC RESET: Select the "Linear" reset to coordinate with
electromechanical time overcurrent relays, in which the reset characteristic (when the
current falls below the reset threshold before tripping) is proportional to ratio of
"energy" accumulated to that required to trip. Select the "Instantaneous" reset to
coordinate with relays, such as most static units, with instantaneous reset
characteristics.
GROUND OC W1(3) GND TIME OC
 
Range:
Range:
Range:
Range:
Range:
Range:
Range:
Range:
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
Enabled, Disabled
1 to 8
Self-Reset, Latched, None
0.05 to 20.00 x CT in steps of
0.01
see description below
0.00 to 100.00 in steps of 0.01
Instantaneous, Linear
Logc Inpt 1 to 16, Virt Inpt 1 to
16, Output Rly 2 to 8, SelfTest
Rly, Vir Outpt 1 to 5, Disabled