ABB RELION REX640 Technical Manual page 504

Protection functions
Figure 285: Overadmittance characteristic. Left figure: classical origin-centered
admittance circle. Right figure: admittance circle is set off from the origin.
Non-directional overconductance characteristic
The non-directional overconductance criterion is enabled with the
setting set to "Go" and
defined with two overconductance boundary lines with the
and
boundary lines can be tilted by the angle defined with the
setting. By default, the tilt angle is zero degrees, that is, the boundary line is a
vertical line in the admittance plane. A positive tilt value rotates the boundary line
counterclockwise from the vertical axis.
In case of non-directional conductance criterion, the
must be set to a smaller value than
Operation is achieved when the measured admittance moves over either of the
boundary lines.
Figure 286: Non-directional overconductance characteristic. Left figure: classical
non-directional overconductance criterion. Middle figure: characteristic is tilted with
negative tilt angle. Right figure: characteristic is tilted with positive tilt angle.
504
Directional mode to "Non-directional". The characteristic is
Conductance reverse settings. For the sake of application flexibility, the
The non-directional overconductance criterion is applicable in high-
resistance earthed and compensated networks. It must not be applied
in unearthed networks.
Conductance reverse setting
Conductance forward .
1MRS759142 F
Operation mode
Conductance forward
Conductance tilt Ang
REX640
Technical Manual