GE 745 - 5.6.5.3 Winding 1 Elements

CHAPTER 5: SETPOINTS S4 ELEMENTS
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL 5–63
5.6.5.3 Winding 1(3) Phase Time Overcurrent
PATH: SETPOINTS  S4 ELEMENTS  PHASE OC  w1(3) PHASE TIME OC
• 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.
IAC short inverse
0.5 0.072 0.047 0.035 0.031 0.028 0.027 0.026 0.026 0.025 0.025
1.0 0.143 0.095 0.070 0.061 0.057 0.054 0.052 0.051 0.050 0.049
2.0 0.286 0.190 0.140 0.123 0.114 0.108 0.105 0.102 0.100 0.099
4.0 0.573 0.379 0.279 0.245 0.228 0.217 0.210 0.204 0.200 0.197
6.0 0.859 0.569 0.419 0.368 0.341 0.325 0.314 0.307 0.301 0.296
8.0 1.145 0.759 0.559 0.490 0.455 0.434 0.419 0.409 0.401 0.394
10.0 1.431 0.948 0.699 0.613 0.569 0.542 0.524 0.511 0.501 0.493
Table 5–9: IAC curve trip times
TDM Current ( I / I
pickup
)
1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
 W1 PHASE []
TIME OC
W1 PHASE TIME OC
FUNCTION: Enabled
Range: Enabled, Disabled
MESSAGE
W1 PHASE TIME OC
RLYS (1-8): --------
Range: 1 to 8
MESSAGE
W1 PHASE TIME OC
TARGET: Latched
Range: Self-Reset, Latched, None
MESSAGE
W1 PHASE TIME OC
PICKUP: 1.20 x CT
Range: 0.05 to 20.00 x CT in steps of
0.01
MESSAGE
W1 PHASE TIME OC
SHAPE: Ext Inverse
Range: see description below
MESSAGE
W1 PHASE TIME OC
MULTIPLIER: 1.00
Range: 0.00 to 100.00 in steps of 0.01
MESSAGE
W1 PHASE TIME OC
RESET: Linear
Range: Instantaneous, Linear
MESSAGE
W1 PHASE TIME OC
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
MESSAGE
W1 HARMONIC DERATING
CORRECTION: Disabled
Range: Logic Input 1 to 16, Disabled