ABB RELION REX640 Technical Manual page 907

1MRS759142 C
REX640
Technical Manual
⋅
(2 X1 zone x + X0 zone x)/3
X1 reverse zone x
* (2 ⋅ X1 zone x + X0 zone x)/3
X1 zone x
-X1 reverse zone x
X1 zone x
GUID-C48FBA72-537D-4B95-ABCD-BE39FF78C266 V1 EN
Figure 494: Tripping characteristic for phase-to-earth impedance measuring
elements if Impedance Chr GND Zn is "Mho (circular)" and
Directional mode Znx is "Non-directional". On the left, Impedance
mode Zn is "Rectangular". On the right, Impedance mode Zn is
"Polar".
Adding of directional lines into circular mho characteristic
Directional lines which are always included in the directional quadrilateral
characteristic can also be included in the mho characteristics to secure the
directionality or to transform the non-directional mho characteristics into a directional
one.
Directional lines with mho are available only when the zone is set to directional, that
is, Directional mode Znx is "Forward" or "Reverse".
The directionality of the directional mho characteristic is secured with directional
lines by setting Impedance Chr Gnd Zn and Impedance Chr PP Zn to "Mho Dir line".
The directional mho characteristic can also be created by adding directional lines in
the offset mho characteristic. This is done by selecting Impedance Chr Gnd Zn and
Impedance Chr PP Zn as "Offset Dir line".
X
α
⋅
(2 R1 zone x + R0 zone x)/3
α
* (2 ⋅ R1 zone x + R0 zone x)/3
Section 4
Protection functions
X
α
R
α
R
901