GE D90 Plus Instruction Manual page 215

CHAPTER 7: PROTECTION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Directional RCA
Range: 30 to 90° in steps of 1
Default: 85°
The setting specifies the characteristic angle (or maximum torque angle) of the
directional supervising function. If the mho shape is applied, the directional function is
an extra supervising function, as the dynamic mho characteristic itself is a directional
one. In conjunction with the quadrilateral shape selection, this setting defines the only
directional function built into the ground distance element. The directional function uses
memory voltage for polarization.
Directional Comparator Limit
Range: 30 to 90° in steps of 1
Default: 90°
This setting specifies the comparator limit angle for the directional supervising function.
Quadrilateral Right Blinder
Range: 0.02 to 500.00 ohms in steps of 0.01
Default: 10.00 ohms
This setting specifies the right blinder position of the quadrilateral characteristic along
the resistive axis of the impedance plane. The angular position of the blinder is
adjustable with the use of the
applies only to the quadrilateral characteristic and should be set with consideration to
the maximum load current and required resistive coverage.
Quadrilateral Right Blinder RCA
Range: 60 to 90° in steps of 1
Default: 85°
This setting specifies the angular position of the right blinder of the quadrilateral
characteristic.
Quadrilateral Left Blinder
Range: 0.02 to 500.00 ohms in steps of 0.01
Default: 10.00 ohms
This setting specifies the left blinder position of the quadrilateral characteristic along the
resistive axis of the impedance plane. The angular position of the blinder is adjustable
with the use of the
Quadrilateral Left Blinder RCA
quadrilateral characteristic and should be set with consideration to the maximum load
current.
Quadrilateral Left Blinder RCA
Range: 60 to 90° in steps of 1
Default: 85°
This setting specifies the angular position of the left blinder of the quadrilateral
characteristic.
Supervision
Range: 0.050 to 30.000 pu in steps of 0.001
Default: 0.200 pu
The ground distance elements are supervised by the magnitude of the neutral (3I_0)
current. The current supervision pickup should be set less than the minimum 3I_0
current for the end of the zone fault, taking into account the desired fault resistance
coverage to prevent maloperation due to VT fuse failure. Settings less than 0.2 pu are
not recommended and should be applied with caution. To enhance ground distance
security against spurious neutral current during switch-off transients, three-phase
faults, and phase-to-phase faults, a positive-sequence current restraint of 5% is applied
to the neutral current supervision magnitude.
GROUPED PROTECTION ELEMENTS
Quadrilateral Right Blinder RCA
setting. This setting applies only to the
setting. This setting
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