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2 CALCULATION OF SETTINGS
2.3 PROTECTION SETTINGS
613: 51GPCKUPFF - 51G Pickup During Fuse Failure
If 51G is directional and potential is lost to the relay, then directional control will be lost and the 51G function
will not provide any protection. To overcome this drawback, a second setting (51GPCKUPFF) provides some
backup during a loss of potential. A 51GPCKUPFF setting must always be set as given above and is based on
the maximum operating quantity that can be obtained for a fault at either end of the line.
614: 51GCURVE - Select 51G Characteristic Curve
2
51GCURVE determines the characteristic curve shape for the 51G function. The choices are inverse curve
(INV; see Figure 2–15: INVERSE CURVE on page 2–49), very inverse curve (V-INV; see Figure 2–16: VERY
INVERSE CURVE on page 2–50), extremely inverse (E-INV; see Figure 2–17: EXTREMELY INVERSE
CURVE on page 2–51), user-defined custom curve (CUSTOM), and definite time (DEFT).
615: 51GTIMDIAL - Ground Time Overcurrent Time Dial
51GTIMDIAL selects the 51G time-dial setting. 51GTIMDIAL can be set from 0.5 to 10.0. The pickup and
time-dial settings should be selected to provide coordination with similar functions in adjacent line sections.
616: DEFTIMDELY - Definite Time Delay
When the 51G function is selected to have a definite time characteristic, DEFTIMDELY determines the associ-
ated fixed time delay. Select a time that meets the specific application.
617: 51G_RESET - Select Time Overcurrent Reset Characteristic
The 51G function can be set to have a very fast reset (approximately 50 milliseconds for the definite time curve
and 4 milliseconds for the variable time curves) following its pickup, or it can be set to have a reset characteris-
tic that emulates the reset time of an electromechanical device with a similar time curve. Select FAST for the
fast reset or EM to emulate an electromechanical function.
2.3.8 VOLTAGE
701: RATEDVOLTS - Rated Per Unit Voltage
This setting establishes the voltage on which per unit voltage values are based. RATEDVOLTS can be set to
100, 105, 110, 115 or 120 volts. Use a setting that is closest to the voltage applied to the LPS-D.
702: PHASEOVER - Select Phase Overvoltage
If the phase overvoltage function is to be used, set PHASEOVER = YES, otherwise set PHASEOVER = NO.
703: PHOVPICKUP - Phase Overvoltage Pickup
PHOVPICKUP can be set from 0.0 to 1.4 per unit based on the RATEDVOLTS setting. Use a setting that
meets the specific application.
704: PHOVTMDLY - Phase Overvoltage Time Delay
PHOVTMDLY establishes a time delay that is started when the phase overvoltage function operates. PHOVT-
MDLY can be set from 0.0 to 10.0 seconds. Use a setting that meets the specific application.
705-713: NOT USED
GE Power Management
LPS-D Line Protection System
2-
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