Ground Current - GE Multilin G650 Manual

5.4 PROTECTION ELEMENTS
Table 5–47: QUANTITIES
POLARIZING MODE
VOLTAGE (Vo)
CURRENT (Ip)
The Ground Current menu incorporates the following overcurrent elements:
5
Ground time overcurrent (51G)
Ground instantaneous overcurrent (50G)
Ground directional element (67G)
Restricted Ground Fault (87G). Enhanced models only.
5.4.5.1 GROUND TIME DELAYED OVERCURRENT ELEMENT (51G)
Ground TOC is a ground time delayed overcurrent protection element. The ground current is measured from the ground
input, terminals B9-B10, and it may be programmed as Fundamental phasor magnitude or RMS magnitude as required by
the application. The element trip can be time delayed using a selectable curve. It incorporates a reset time that is selectable
between instantaneous or linear.
Table 5–48: 51G ELEMENT SETTINGS
SETPOINT > PROTECTION ELEMENTS > GROUND CURRENT > GROUND TOC
GROUND TOC 1> GROUND TOC 2 > GROUND TOC 3
SETTING DESCRIPTION
Function permission
Input type
Pickup level
Curve shape
Time Dial
Reset type
Snapshot Event generation
The snapshot event setting enables or disables the snapshot event generation for this element.
5-52
DIRECTION
FORWARD
REVERSE
FORWARD
REVERSE
FORWARD
Vo + Ip
REVERSE
FORWARD
Vo * Ip
REVERSE
NAME
Function
Input
Pickup Level
Curve
TD Multiplier
Reset
Snapshot Events
G650 Generator Protection & Control System
COMPARED PHASORS
-Vo
-Vo
Isg
Isg
- Vo
Isg
- Vo
Isg
- Vo
Isg
- Vo
Isg
DEFAULT VALUE STEP
DISABLED N/A
PHASOR(DFT) N/A
1.00 0.01 A
IEEE Ext Inv N/A
1.00 0.01 s
INSTANTANEOUS N/A
ENABLED N/A
5 SETTINGS
Io x 1 MTA
-Io x 1 MTA
Io
-Io
Io
or
Io
-Io
or
-Io
Io
and
Io
-Io
and
-Io

5.4.5 GROUND CURRENT

RANGE
[DISABLED – ENABLED]
[PHASOR – RMS]
[0.05 : 160.00]
[See list of curves]
[0.00 : 900.00]
[INSTANTANEOUS – LINEAR]
[DISABLED – ENABLED]
GEK-113285A