Ground Current; Ground Time Delayed Overcurrent Unit (51G); Ground Instantaneous Overcurrent Unit (50G); 51G Unit Setpoints - GE Multilin F650 Instruction Manual

5.4 PROTECTION ELEMENTS
The F650 Ground Current menu incorporates the following overcurrent elements:
Ground time overcurrent (51G)
Ground instantaneous overcurrent (50G)
Ground directional unit (67G)

5.4.5.1 GROUND TIME DELAYED OVERCURRENT UNIT (51G)

51G unit is a ground time delayed overcurrent protection element. The ground current input quantity is measured from the
magnetic module ground input, terminals B9-B10, and it may be programmed as Fundamental phasor magnitude or total
waveform RMS magnitude as required by the application. The unit trip can be time delayed using a selectable curve. And it
incorporates a reset time selectable between instantaneous or linear.
Table 5–49: 51G UNIT SETPOINTS
SETPOINT > PROTECTION ELEMENTS > GROUND CURRENT > GROUND TOC
GROUND TOC 1> GROUND TOC 2 > GROUND TOC 3
SETPOINT DESCRIPTION
Function permission
Input type
Pickup level
5
Curve shape
Time Dial
Reset type
Snapshot Event generation
The snapshot event setpoint enables or disables the snapshot event generation for this unit.

5.4.5.2 GROUND INSTANTANEOUS OVERCURRENT UNIT (50G)

50G unit is a ground instantaneous overcurrent protection element, with a setpoint range from 0.05 A to 160 A, which can
also be time delayed, with a delay selectable between 0.00 and 900 seconds. The ground current input quantity is
measured from the transformers module ground input, and it may be programmed as Fundamental phasor magnitude or
total waveform RMS magnitude as required by the application. The unit incorporates a reset time selectable between 0 and
900 seconds, and a block input that resets the pickup and trip signals to 0. The unit outputs are the general pickup and trip
signals of the unit.
Table 5–50: 50G UNIT SETPOINTS
SETPOINT > PROTECTION ELEMENTS > GROUND CURRENT > GROUND IOC
GROUND IOC 1> GROUND IOC 2 > GROUND IOC 3
SETPOINT DESCRIPTION
Function permission
Input type
Pickup level
Trip time
Reset time
Snapshot event generation
The snapshot event setpoint enables or disables the snapshot event generation for this unit.
5-56
NAME DEFAULT VALUE
Function DISABLED
Input PHASOR(DFT)
Pickup Level 1.00
Curve IEEE Ext Inv
TD Multiplier 1.00
Reset INSTANTANEOUS N/A
Snapshot Events ENABLED
NAME DEFAULT VALUE STEP
Function DISABLED
Input PHASOR(DFT)
Pickup Level 30.00
Trip Delay 0.00
Reset Delay 0.00
Snapshot Events ENABLED
F650 Digital Bay Controller

5.4.5 GROUND CURRENT

STEP RANGE
N/A [DISABLED – ENABLED]
N/A [PHASOR – RMS]
0.01 A [0.05 : 160.00]
N/A [See list of curves]
0.01 s [0.00 : 900.00]
[INSTANTANEOUS – LINEAR]
N/A [DISABLED – ENABLED]
RANGE
N/A [DISABLED – ENABLED]
N/A [PHASOR – RMS]
0.01 A [0.05 : 160.00]
0.01 s [0.00 : 900.00]
0.01 s [0.00 : 900.00]
N/A [DISABLED – ENABLED]
5 SETPOINTS
GE Multilin