GE D90 Plus Instruction Manual page 217

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; set it 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; set it 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. Set the current supervision pickup to be less than the minimum 3I_0 current for
the end of the zone fault, taking into account the required fault resistance coverage to
prevent maloperation due to VT fuse failure. Settings less than 0.2 pu are not
recommended, so apply them 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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