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.
X
R
Forward
X
R
Reverse Non-directional
X
R
Max Ris Gnd Rch Znx
Tilt angle zone x
Min Ris Gnd Rch Znx
Max Ris Gnd Rch Znx
Tilt angle zone x
Min Ris Gnd Rch Znx
Min Ris Gnd Rch Znx
Min Ris Gnd Rch Znx
Min Ris Gnd Rch Znx Min Ris Gnd Rch Znx
Tilt angle zone x
Tilt angle zone x
Figure 547: 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.
1MRS759142 F
Protection functions
REX640
Technical Manual
973
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