Voltage - GE ALPS Instruction Manual

2 CALCULATION OF SETTINGS 2.3 PROTECTION SETTINGS
611: 51G_DIRCNL - Select Directional Control of TOC
51G_DIRCNL can be set to either YES or NO. This setting determines whether 51G is directionally controlled (YES) or not
directionally controlled (NO).
612: 51GPICKUP - Ground Time Overcurrent Setting
51G provides time delayed backup tripping for single-line-to-ground faults. Its operating quantity is:
2
×
3 I
0
The curve shape used for 51G is determined by the 51GCURVE setting as described below. The pickup and time dial set-
tings should be selected to provide coordination with similar functions in adjacent line sections.
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
51GCURVE determines the characteristic curve shape for the 51G function. The choices are inverse curve (INV, Figure 2–
18: INVERSE CURVE on page 2–48), very inverse curve (V-INV, Figure 2–19: VERY INVERSE CURVE on page 2–49),
extremely inverse curve (E-INV, Figure 2–20: EXTREMELY INVERSE CURVE on page 2–50), 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 associated 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 milli-
seconds for the variable time curves) following its pickup, or it can be set to have a reset characteristic 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 elec-
tromechanical 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 that is applied to the ALPS.
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 spe-
cific application.
704: PHOVTMDLY - Phase Overvoltage Time Delay
PHOVTMDLY establishes a time delay that is started when the phase overvoltage function operates. PHOVTMDLY can be
set from 0.0 to 10.0 seconds. Use a setting that meets the specific application.
GE Power Management ALPS Advanced Line Protection System 2-27