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2.10.3 Element characteristic in distance relay
The distance protection function has six measurement zones; it is possible to identify the fault
point using these zones. This function has ZS elements to determine phase-to-phase faults and
ZG elements to determine single-phase-earth faults.
This distance protection function can be selected to have either a Mho characteristic
(Mho) or a Quadrilateral characteristic (Quad) for both ZS and ZG. Each of the measuring
zones in this function has a directional characteristic.
Note: The Asterisk (*) in the setting is used to show the zone number in ZS/ZG (either
"1", "1X", "2", "3", "4", or "5"). The numbering and application of ZS/ZG are
described later.
(i) Common characteristic of ZS and ZG
The distance protection function has a Mho characteristic (Mho) element and a Quadrilateral
characteristic (Quad) element and either the Mho characteristic or the Quad characteristic is
selected by the scheme switches [ZS-Chara] and [ZG-Chara].
Note: The complete elements and their characteristics, ZS and ZG are based on the
scheme switches [ZS-Chara] and [ZG-Chara].
Mho characteristic
(i)-1-1 Conventional Mho characteristic
Figure 2.10-11(a) and (b) show Z*S and Z*G with the Mho characteristic. The Z*S can
be set using the settings [Z*S-Mho.Reach] and [Z*S-Mho.Angle].
The blinder positions (left line and right line) are defined by the resistance and the
angle in the Figure 2.10-11; they are set using settings [Z*S-R.Reach] and [Z*S-
R.Angle]. The blinders are aligned symmetrically with the X-coordinate. Scheme
switches [Z*S-MhoR.EN] should be set On to enable the blinders.
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