GE D90 Plus Instruction Manual page 215

CHAPTER 7: PROTECTION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Z0/Z1 Magnitude
Range: 0.00 to 10.00 in steps of 0.01
Default: 2.70
This setting specifies the ratio between the zero-sequence and positive-sequence
impedance required for zero-sequence compensation of the ground distance elements.
This setting is available on a per-zone basis, enabling precise settings for tapped, non-
homogeneous, and series compensated lines.
Z0/Z1 Angle
Range: –90 to 90° in steps of 1
Default: 0°
This setting specifies the angle difference between the zero-sequence and positive-
sequence impedance required for zero-sequence compensation of the ground distance
elements. The entered value is the zero-sequence impedance angle minus the positive-
sequence impedance angle. This setting is available on a per-zone basis, enabling
precise values for tapped, non-homologous, and series-compensated lines.
Z0M/Z1 Magnitude
Range: 0.00 to 7.00 in steps of 0.01
Default: 0.00
The ground distance elements can be programmed to apply compensation for the zero-
sequence mutual coupling between parallel lines. If this compensation is required, the
ground current from the parallel line (3I_0) measured in the direction of the zone being
compensated must be connected to the ground input CT of the CT bank configured in
the Distance > Common > Source setting. This setting specifies the ratio between the
magnitudes of the mutual zero-sequence impedance between the lines and the
positive-sequence impedance of the protected line. Set this setting to zero if the
compensation is not to be performed.
Z0M/Z1 Angle
Range: –90 to 90° in steps of 1
Default: 0°
This setting specifies the angle difference between the mutual zero-sequence
impedance between the lines and the positive-sequence impedance of the protected
line.
Reach
Range: 0.02 to 500.00 ohms in steps of 0.01
Default: 2.00 ohms
This setting specifies the reach of the zone for the forward and reverse applications. In
non-directional applications, this setting defines the forward reach of the zone. The
reverse reach impedance in non-directional applications is set independently. The angle
of the reach impedance is entered as the
secondary ohms.
RCA
Range: 30 to 90° in steps of 1
Default: 85°
This setting specifies the characteristic angle (similar to the maximum torque angle in
previous technologies) of the ground distance characteristic for the forward and reverse
applications. In the non-directional applications, this setting defines the forward reach
of the zone. The reverse reach impedance in the non-directional applications is set
independently. This setting is independent from the
characteristic angle of an extra directional supervising function).
GROUPED PROTECTION ELEMENTS
RCA setting. The reach impedance is entered in
Directional RCA
setting (the
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