5.5 GROUPED ELEMENTS
The ground MHO distance function uses a dynamic 100% memory-polarized mho characteristic with additional reactance,
directional, current, and phase selection supervising characteristics. The ground quadrilateral distance function is com-
posed of a reactance characteristic, right and left blinders, and 100% memory-polarized directional, overcurrent, and phase
selection supervising characteristics.
The reactance supervision uses zero-sequence current as a polarizing quantity making the characteristic adaptable to the
pre-fault power flow. The directional supervision uses memory voltage as polarizing quantity and both zero- and negative-
sequence currents as operating quantities.
The phase selection supervision restrains the ground elements during double-line-to-ground faults as they – by principles
of distance relaying – may be inaccurate in such conditions. The ground distance element applies additional zero-
sequence directional supervision.
The setting menu configures the basic distance settings except for:
Signal Source (common for both phase and ground elements as entered under the
SETTING GROUP 1(8)
Memory duration (common for both phase and ground elements as entered under the
SETTING GROUP 1(8)
The common distance settings noted at the start of the DISTANCE section must be properly chosen for correct operation of
the ground distance elements.
Ensure that the
menu) is set correctly to prevent improper operation of associated memory action.
GND DIST Z2 DIRECTION:
The zone is reversible. The forward direction is defined by the
by 180° from that angle.
GND DIST Z2 SHAPE:
This setting selects the shape of the ground distance characteristic between the mho and quad characteristics.
GND DIST Z2 Z0/Z1 MAG:
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 enables precise settings for tapped, non-homogeneous, and
series compensated lines.
GND DIST Z2 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 enables precise values for tapped, non-homologous, and series-compensated lines.
GND DIST Z2 ZOM/Z1 MAG:
The ground distance elements can be programmed to apply compensation for the zero-sequence mutual coupling between
parallel lines. If the compensation is required, the ground current from the parallel line (3I_0) measured in the direction of
zone being compensated must be connected to the ground input CT of the CT bank configured under the
. 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. It is imperative to set this setting to zero if the compensa-
tion is not to be performed.
GND DIST Z2 ZOM/Z1 ANG:
This setting specifies the angle difference between the mutual zero-sequence impedance between the lines and the posi-
tive-sequence impedance of the protected line.
GND DIST Z2
PHASE VT SECONDARY VOLTAGE
L90 Line Differential Relay
Range: Disabled, Enabled
setting and the reverse direction is shifted
GND DIST Z2 RCA
GE Power Management