ABB RELION REX640 Technical Manual page 900

Section 4
Protection functions
894
The total reactive reach in reverse direction includes a part which is defined by the
residual compensation factor K
same for forward and reverse direction.
Forward
X
α
R
GUID-D19BE269-3658-45B3-8FC8-94E8B6447437 V1 EN
Figure 487: Settings which define the line reach for phase-to-earth impedance
measuring elements if Impedance mode Zn = "Polar"
Protection zone characteristics
DSTPDIS has both "Quadrilateral" and "Mho (circular)" characteristics available for
the protection zones and they can be combined also with the bullet characteristic. The
shape of a tripping characteristic can be set independently for phase-to-earth, phase-
to-phase or three-phase impedance elements. The zone shape is defined with the
Impedance Chr Gnd Zn setting for phase-to-earth impedance elements, and with the
Impedance Chr PP Zn setting for phase-to-phase or three-phase impedance elements.
The alternatives are "Quadrilateral", "Mho (circular)", "Mho Dir line", "Offset Dir
line" and "Bullet (combi)".
All impedance values defining the zone shape are entered in primary ohms. Angles are
given in degrees.
Quadrilateral characteristic
If the zone has the "Quadrilateral" shape, DSTPDIS has a polygonal tripping
characteristic.
. The characteristic line angle, denoted as α, is the
N
Reverse
X
R
α
1MRS759142 C
Non-directional
X
α
R
α
REX640
Technical Manual