GE D30 Instruction Manual page 291

5 SETTINGS
Figure 5–66: NON-DIRECTIONAL QUADRILATERAL GROUND DISTANCE CHARACTERISTIC
• GND DIST Z1 Z0/Z1 MAG: This setting specifies the ratio between the zero-sequence and positive-sequence imped-
ance 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.
• GND DIST Z1 Z0/Z1 ANG: 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.
• GND DIST Z1 ZOM/Z1 MAG: 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 under the
zero-sequence impedance between the lines and the positive-sequence impedance of the protected line. It is impera-
tive to set this setting to zero if the compensation is not to be performed. Note that internally the mutual coupling com-
pensation is applied only if 3I_0>1.22*IG to ensure that no mutual coupling compensation is applied when the fault is
on the parallel line. Mutual coupling compensation is applied when distance source is assigned with 8F or 8L type DSP
module only and when the ratio of the protected line ground current to parallel line ground current is greater than 1.22.
• GND DIST Z1 ZOM/Z1 ANG: This setting specifies the angle difference between the mutual zero-sequence imped-
ance between the lines and the positive-sequence impedance of the protected line.
• GND DIST Z1 REACH: This setting defines 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-direc-
tional applications is set independently. The angle of the reach impedance is entered as the
The reach impedance is entered in secondary ohms.
To achieve specified operating speed of distance elements, the relay internally calculates source to line impedance
ratio (SIR) from fault phasors. In these calculations, line impedance is estimated based on the zone 1 reach setting.
Therefore, in order to calculate the SIR value properly and to maintain the optimal operating speed of the distance ele-
ments, you need to set zone 1 reach with a regular 80 to 85% of the line impedance reach setting, even when zone 1
is disabled.
• GND DIST Z1 RCA: 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
GE Multilin
X
COMP LIMIT COMP LIMIT
LFT BLD RCA RCA
-LFT BLD
REV REACH
RCA
COMP LIMIT COMP LIMIT
"-" NON-HOMOGEN. ANG
"+" NON-HOMOGEN. ANG
. This setting specifies the ratio between the magnitudes of the mutual
DISTANCE SOURCE
D30 Line Distance Protection System
5.6 GROUPED ELEMENTS
"+" NON-HOMOGEN. ANG
"-" NON-HOMOGEN. ANG
RGT BLD RCA
R
RGT BLD
837770A1.CDR
5
setting.
GND DIST Z1 RCA
5-155