ABB 615 series Technical Manual page 395

1MAC059074-MB A
615 series ANSI
Technical Manual
Im(Yo)
TRIP
Re(Yo)
Conductance forward
TRIP
GUID-3D218EC0-4681-471D-B279-52D7810C1A24 V1 EN
Figure 183: Forward directional overconductance characteristic. Left figure: classical
forward directional overconductance criterion. Middle figure:
characteristic is tilted with negative tilt angle. Right figure: characteristic
is tilted with positive tilt angle.
Forward directional oversusceptance characteristic
The forward directional oversusceptance criterion is enabled with the Operation mode
setting set to "Bo" and Directional mode to "Forward". The characteristic is defined by
one oversusceptance boundary line with the Susceptance forward setting. For the sake of
application flexibility, the boundary line can be tilted by the angle defined with the
Susceptance tilt Ang setting. By default, the tilt angle is zero degrees, that is, the boundary
line is a horizontal line in the admittance plane. A positive tilt value rotates the boundary
line counterclockwise from the horizontal axis.
Operation is achieved when the measured admittance moves over the boundary line.
The forward directional oversusceptance criterion is applicable in
ungrounded networks. It must not be applied to compensated networks.
Protection functions
Im(Yo)
Conductance tilt Ang <0
TRIP
Re(Yo)
Conductance forward
TRIP
Section 4
Im(Yo)
Conductance tilt Ang >0
TRIP
Re(Yo)
Conductance forward
TRIP
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