ERL L-PRO 4000, Руководство пользователя

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4 Protection Functions and Specifications
D02706R02.30 L-PRO 4000 User Manual 4-3
Figure 4.1: Phase and Ground distance protection Mho relay characteristic
The shape of the phase and ground distance relays is adjustable. For the circu-
lar Mho characteristic shape, the characteristic angle is 90 degrees. Determine
this angle by drawing 2 lines from any point on the impedance locus to the di-
ameter of the characteristic. Produce a tomato-shaped characteristic by select-
ing an angle less than 90 degrees or a lens-shaped characteristic with angles
greater than 90 degrees.
Figure 4.2: Phase and Ground distance protection Quadrilateral Characteristics
The shape of the Mho characteristic means that significant extensions are made
to the relay characteristics in the R region of the R-X plane for ground faults.
R
X
Zone 5
Zone 3
Zone 2
Zone 1
Zone 4
Line Z1
Line Angle
Characteristic Angle
R
X X
Zone 5
Zone 3
Zone 2
Zone 1
Zone 4
Line Angle
Line Z1
Forward
Reverse
Directional Element