3-2 735/737 Feeder Protection Relay
GE Power Management
3.2 CONTROLS 3 SETUP AND OPERATION
3
3.2 CONTROLS 3.2.1 PHASE PICKUP [1]
This control determines the pickup current for overcurrent timeout for any phase curve shape and curve multiplier. It is set
as a percentage of phase CT rating. Read the pickup current from the inner LO band when the phase CURVE SHAPE is
set to a LO range (20 to 100%). Use the outer HI band if the phase CURVE SHAPE is set to a HI range (110 to 220%).
Select the OFF position to disable phase time overcurrent.
Figure 3–2: PHASE PICKUP SETTING
3.2.2 PHASE CURVE SHAPE [2]
Five different curve shapes can be selected for the phase time overcurrent to provide the required coordination. These are
definite time, moderately inverse, normal inverse, very inverse and extremely inverse. For each curve, either the LO band
or HI band of the phase pickup setting (Control 1) is selected. See the time overcurrent figures for actual curves and curve
values in table form.
For example: CURVE SHAPE: normal inverse
PICKUP CURRENT: 480 A
PHASE CT RATIO: 600:5
PHASE CURVE SHAPE: normal inverse LO
PHASE PICKUP: 80/180 (480 A = 80% of 600 A)
Figure 3–3: PHASE CURVE SHAPE SETTING
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