5–68 745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
S4 ELEMENTS CHAPTER 5: SETPOINTS
5.6.6.3 Neutral Instantaneous Overcurrent
PATH: SETPOINTS S4 ELEMENTS NEUTRAL OC W1(3) NTRL INST OC 1(2)
• W1(3) NEUTRAL INST OC 1(2) PICKUP: Enter the level of neutral current (in units of
relay nominal current) above which the winding 1(3) neutral instantaneous
overcurrent 1 element will pickup and start the delay timer.
• W1(3) NEUTRAL INST OC 1(2) DELAY: Enter the time that the neutral current must
remain above the pickup level before the element operates.
Note
The setpoint messages above and the following logic diagram are identical for the
neutral instantaneous overcurrent 2 element.
FIGURE 5–19: Neutral instantaneous overcurrent scheme logic
W1 NTRL []
INST OC 1
W1 NEUTRAL INST OC 1
FUNCTION: Enabled
Range: Enabled, Disabled
MESSAGE
W1 NEUTRAL INST OC 1
RLYS (1-8): --------
Range: 1 to 8
MESSAGE
W1 NEUTRAL INST OC 1
TARGET: Latched
Range: Self-Reset, Latched, None
MESSAGE
W1 NEUTRAL INST OC 1
PICKUP: 10.00 x CT
Range: 0.05 to 20.00 x CT in steps of
0.01
MESSAGE
W1 NEUTRAL INST OC 1
DE L AY: 0 ms
Range: 0 to 60000 ms in steps of 1
MESSAGE
W1 NEUTRAL INST OC 1
BLOCK: Disabled
Range: 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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