GE D90 Plus Instruction Manual page 208

GROUPED PROTECTION ELEMENTS
198
Quadrilateral Right Blinder
Range: 0.02 to 500.00 ohms in steps of 0.01
Default: 0.90 ohms
This setting specifies the right blinder position of the quadrilateral characteristic along
the resistive axis of the impedance plane (see the Quadrilateral Phase Distance
Characteristic figures). The angular position of the blinder is adjustable with the use of
the
Quadrilateral Right Blinder RCA
characteristic and is set giving 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 (see the Quadrilateral Phase Distance Characteristic figures).
Quadrilateral Left Blinder
Range: 0.02 to 500.00 ohms in steps of 0.01
Default: 0.85 ohms
This setting specifies the left blinder position of the quadrilateral characteristic along the
resistive axis of the impedance plane (see the Quadrilateral Phase Distance
Characteristic figures). The angular position of the blinder is adjustable with the use of
the
Quadrilateral Left Blinder RCA
characteristic and is set with consideration to the maximum load current.
Quad 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 (see the Quadrilateral Phase Distance Characteristic figures).
Supervision
Range: 0.050 to 30.000 pu in steps of 0.001
Default: 0.200 pu
The phase distance elements are supervised by the magnitude of the line-to-line current
(fault loop current used for the distance calculations). For convenience, √3 is
accommodated by the pickup (that is, before being used, the entered value of the
threshold setting is multiplied by √3).
If the minimum fault current level is sufficient, set the current supervision pickup above
maximum full load current preventing maloperation under VT fuse fail conditions. This
requirement can be difficult to meet for remote faults at the end of zones 2 through 5. If
this is the case, set the current supervision pickup below the full load current, but this
can result in maloperation during fuse fail conditions.
Zone 1 is sealed-in with current supervision.
Voltage Level
Range: 0.000 to 5.000 pu in steps of 0.001
Default: 0.000 pu
This setting is relevant for applications on series-compensated lines, or in general, if
series capacitors are located between the relaying point and a point where the zone
does not overreach. For plain (non-compensated) lines, set to zero. Otherwise, the
setting is entered in per unit of the phase VT bank configured in the distance
setting. Effectively, this setting facilitates dynamic current-based reach reduction. In
non-directional applications (the
only to the forward reach of the non-directional zone.
setting. This setting applies only to the quadrilateral
setting. This setting applies only to the quadrilateral
Direction is set to "Non-directional"), this setting applies
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
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