Sensitive Ground Current (Only For Enhanced Models) - GE Multilin G650 Manual

5 SETTINGS
The G650 Sensitive ground Current menu incorporates the following overcurrent elements:
• Sensitive ground time overcurrent (51SG)
• Sensitive ground instantaneous overcurrent (50SG)
5.4.7.1 SENSITIVE GROUND TIME DELAYED OVERCURRENT ELEMENT (51SG)
Sensitive Ground TOC is a sensitive ground time delayed overcurrent protection element with a setting range 0.005A to
16A. The sensitive ground current input quantity is measured from the sensitive ground input, terminals B11-B12, 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. And it incorporates a reset time selectable between instantaneous or linear.
Table 5–59: 51SG ELEMENT SETTINGS
SETPOINT > PROTECTION ELEMENTS > SENSITIVE GROUND CURRENT > SENSITIVE GROUND TOC
SENSITIVE GROUND TOC 1> SENSITIVE GROUND TOC 2 > SENSITIVE 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.
5.4.7.2 SENSITIVE GROUND INSTANTANEOUS OVERCURRENT ELEMENT (50SG)
50SG is a sensitive ground instantaneous overcurrent protection element, with a setting range from 0.005 A to 16.00 A,
which can also be time delayed, with a delay selectable between 0 and 900 seconds. The ground current input quantity is
measured from the sensitive ground input, and it may be programmed as fundamental phasor magnitude or RMS
magnitude as required by the application. The element incorporates a reset time selectable between 0 and 900 seconds,
and a block input that resets the pickup and trip signals to 0. The element outputs are the general pickup and trip signals of
the element.
Table 5–60: 50SG ELEMENT SETTINGS
SETPOINT > PROTECTION ELEMENTS > SENSITIVE GROUND CURRENT > SENSITIVE GROUND IOC
SENSITIVE GROUND IOC 1> SENSITIVE GROUND IOC 2 > SENSITIVE GROUND IOC 3
SETTING DESCRIPTION
Function permission
Input type
Pickup level
Trip time
Reset time
Snapshot event generation
The snapshot event setting enables or disables the snapshot event generation for this element.
GEK-113285A

5.4.7 SENSITIVE GROUND CURRENT (ONLY FOR ENHANCED MODELS)

NAME DEFAULT VALUE
Function DISABLED
Input PHASOR(DFT)
Pickup Level 0.050
Curve IEEE Ext Inv
TD Multiplier 1.00
Reset INSTANTANEOUS
Snapshot Events ENABLED
NAME DEFAULT VALUE
Function DISABLED
Input PHASOR(DFT)
Pickup Level 0.100
Trip Delay 0.00
Reset Delay 0.00
Snapshot Events ENABLED
G650 Generator Protection & Control System
5.4 PROTECTION ELEMENTS
STEP RANGE
N/A [DISABLED – ENABLED]
N/A [PHASOR – RMS]
0.001 A [0.005 : 16.000]
N/A [See list of curves]
0.01 s [0.00 : 900.00]
N/A [INSTANTANEOUS – LINEAR]
N/A [DISABLED – ENABLED]
STEP RANGE
N/A [DISABLED – ENABLED]
N/A [PHASOR – RMS]
0.001 A [0.005 : 16.000]
0.01 s [0.00 : 900.00]
0.01 s [0.00 : 900.00]
N/A [DISABLED – ENABLED]
5
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