GE F650 Instruction Manual page 215

5.4 PROTECTION ELEMENTS
5.4.6.4 SENSITIVE GROUND DIRECTIONAL ELEMENT (67SG)
Sensitive Ground directional is a directional element used for supervising sensitive ground overcurrent functions. The
operation magnitude is the ground current measured directly from the corresponding input (terminals B11-B12), while the
polarization magnitude is the neutral voltage (3Vo). The neutral voltage is either calculated from three phase voltages or
measured from the dedicated voltage input (A11-A12)
In case of using the voltage measured at the dedicated voltage input terminals, the Auxiliary Voltage setting in Setpoint >
System Setup > General settings must be VN.
If the F650 is set to have synchronism check protection, then this input will be adjusted as busbar voltage and it will not be
the 3V0 voltage (AUXILIARY VOLTAGE setting as VX)
If the F650 does not have a synchronism check element, then this input can be set as 3V0 neutral voltage, and it can be
used as polarization magnitude for the 67SG element (AUXILIARY VOLTAGE setting as VN).
The same way as the directional element for phases, it has a polarization voltage loss logic that allows blocking or
producing trip depending on the setting.
Table 5–61: SENSITIVE GROUND DIRECTIONAL ELEMENT SETTINGS
SETPOINT > PROTECTION ELEMENTS > SENSITIVE GROUND CURRENT > SENSITIVE GROUND DIRECTIONAL >
SENSITIVE GROUND DIRECTIONAL 1> SENSITIVE GROUND DIRECTIONAL 2 > SENSITIVE GROUND DIRECTIONAL 3
SETTING DESCRIPTION
Function permission
Maximum Torque Angle
Operation Direction
Block logic type
5
Polarization voltage threshold
Snapshot event generation
Available settings are:
Function permission (Function): This setting determines whether the sensitive Ground directional element is enabled or
Maximum Torque Angle (MTA): This angle is used to rotate the Polarization voltage. Positive angles mean counter
Operation Direction (Direction): This setting indicates the Direction for which the element will allow a trip. Depending on
Polarization Voltage Threshold (Pol. V Threshold):This is the minimum polarization voltage threshold. For a voltage
Snapshot Events:
Sensitive ground directional element is an independent Protection element that provides block and Operation signals.
These signals can be monitored both through the relay HMI or using EnerVista 650 Setup at "Actual > Status > Protection
> Sensitive Ground Current"
5-68
NAME DEFAULT VALUE
Function DISABLED
MTA -45
Direction FORWARD
Block Logic PERMISSION
Pol V Threshold 10
Snapshot Events ENABLED
Disabled.
clockwise rotation, and negative angles mean clockwise. The polarization magnitude,
once rotated, defines the MTA line. Vn rotated by this angle points to the semi plane
that corresponds to a Reverse fault. (-Vn) rotated this angle points to the semi plane
that corresponds to a Forward fault.
this setting, the element will be activated for faults in a direction or in the opposite
direction. Possible setting values are FORWARD or REVERSE.
value lower than this setting the directional element will be blocked.
The snapshot event setting enables or disables the snapshot event generation for this
element.
F650 Digital Bay Controller
5 SETTINGS
STEP RANGE
N/A [DISABLED – ENABLED]
1 Deg [-90 : +90]
N/A [FORWARD – REVERSE]
N/A [BLOCK – PERMISSION]
1 V [0 : 300]
N/A [DISABLED – ENABLED]
GEK-106310AB