ABB RELION REX640 Technical Manual page 901

1MRS759142 C
REX640
Technical Manual
Forward
Max Ris Gnd Rch Znx
X
Tilt angle zone x
R
Min Ris Gnd Rch Znx
Max Ris Gnd Rch Znx
Tilt angle zone x
GUID-1CD8F147-7A9F-4F73-B373-792C248A1BA0 V1 EN
Figure 488: Tripping characteristic for phase-to-earth impedance elements if the
zone shape is quadrilateral. The tilt angle is set to compensate for
possible under- or overreaching.
The reach in the reactive direction is defined by the line reach independently for
phase-to-earth and for phase-to-phase/three-phase elements. The resistive reach is
defined at the minimum and maximum resistive reach with settings Min Ris Gnd Rch
Znx, Max Ris Gnd Rch Znx, Min Ris PP Rch Znx, Max Ris PP Rch Znx (x = 1...5). In
case of a non-directional zone, only settings Min Ris Gnd Rch Znx and Min Ris PP Rch
Znx (x = 1...5) are valid. The resistive reach can be set independently for phase-to-
earth and for phase-to-phase or three-phase elements.
In case of phase-to-earth impedance elements, the resistive reach value corresponds to
the physical fault resistance between phase and earth including arc and earthing
resistance.
The reactive reach can be adjusted by tilting the top reactance boundary line by an
angle defined with Tilt angle zone x (x = 1...5). The negative value decreases the
tripping zone area while the positive value increases the tripping area. The negative
value is used in case of underreaching zones to compensate a possible overreaching.
The positive value is used in case of overreaching zones to compensate a possible
underreaching.
Reverse
Min Ris Gnd Rch Znx
X
Min Ris Gnd Rch Znx
R
Tilt angle zone x
Min Ris Gnd Rch Znx
Section 4
Protection functions
Non-directional
Min Ris Gnd Rch Znx
X
Tilt angle zone x
R
Min Ris Gnd Rch Znx
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