ABB 615 series Technical Manual page 393

1MAC059074-MB A
615 series ANSI
Technical Manual
The overadmittance criterion is typically applied in ungrounded networks, but it can also
be used in compensated networks, especially if the circle is set off from the origin.
Im(Yo)
TRIP
Circle radius
TRIP
GUID-202AAFD7-C61F-4169-881E-25757CECE368 V1 EN
Figure 181: 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 Operation mode setting
set to "Go" and Directional mode to "Non-directional". The characteristic is defined with
two overconductance boundary lines with the Conductance forward and Conductance
reverse settings. For the sake of application flexibility, the boundary lines can be tilted by
the angle defined with the Conductance tilt Ang 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 Conductance reverse setting must be
set to a smaller value than Conductance forward.
Operation is achieved when the measured admittance moves over either of the boundary
lines.
The non-directional overconductance criterion is applicable in high-
resistance grounded and compensated networks. It must not be applied in
ungrounded networks.
TRIP TRIP
Re(Yo)
Circle radius
Circle conductance
TRIP TRIP
Section 4
Protection functions
Im(Yo)
TRIP
Re(Yo)
Circle susceptance
TRIP
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