GE 745 Instruction Manual page 159

CHAPTER 5: SETPOINTS
5.6.5.3 Winding 1(3) Phase Time Overcurrent
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W1 PHASE
TIME OC
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
TDM
1.5 2.0
0.5 0.072 0.047
1.0 0.143 0.095
2.0 0.286 0.190
4.0 0.573 0.379
6.0 0.859 0.569
8.0 1.145 0.759
10.0 1.431 0.948
PATH: SETPOINTS
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• W1(3) PHASE TIME OC PICKUP: Enter the phase current level (in units of relay nominal
current) above which the winding 1(3) phase time overcurrent element will pickup and
start timing.
• W1(3) PHASE TIME OC SHAPE: Select the time overcurrent curve shape to use for the
winging 1(3) phase time overcurrent. Time Overcurrent Curves on page 5–59 describes
the time overcurrent curve shapes.
• W1(3) PHASE 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) PHASE TIME OC RESET: Select "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 "Instantaneous" reset to
coordinate with relays, such as most static units, with instantaneous reset
characteristics.
Table 5–9: IAC curve trip times
Current ( I / I
3.0 4.0 5.0
IAC short inverse
0.035 0.031 0.028
0.070 0.061 0.057
0.140 0.123 0.114
0.279 0.245 0.228
0.419 0.368 0.341
0.559 0.490 0.455
0.699 0.613 0.569
S4 ELEMENTS PHASE OC

W1 PHASE TIME OC
FUNCTION: Enabled
W1 PHASE TIME OC
RLYS (1-8): --------
W1 PHASE TIME OC
TARGET: Latched
W1 PHASE TIME OC
PICKUP: 1.20 x CT
W1 PHASE TIME OC
SHAPE: Ext Inverse
W1 PHASE TIME OC
MULTIPLIER: 1.00
W1 PHASE TIME OC
RESET: Linear
W1 PHASE TIME OC
BLOCK: Disabled
W1 HARMONIC DERATING
CORRECTION: Disabled
S4 ELEMENTS
)
pickup
6.0 7.0 8.0
0.027 0.026 0.026 0.025
0.054 0.052 0.051 0.050
0.108 0.105 0.102 0.100
0.217 0.210 0.204 0.200
0.325 0.314 0.307 0.301
0.434 0.419 0.409 0.401
0.542 0.524 0.511 0.501
w1(3) PHASE TIME OC

Range: Enabled, Disabled
Range: 1 to 8
Range: Self-Reset, Latched, None
Range: 0.05 to 20.00 x CT in steps of
0.01
Range: see description below
Range: 0.00 to 100.00 in steps of 0.01
Range: Instantaneous, Linear
Range: Logc Inpt 1 to 16, Virt Inpt 1 to
16, Output Rly 2 to 8, SelfTest
Rly, Vir Outpt 1 to 5, Disabled
Range: Logic Input 1 to 16, Disabled
9.0 10.0
0.025
0.049
0.099
0.197
0.296
0.394
0.493
5–63