Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.67 Quadrilateral Phase-Distance Element Characteristic (TANGP = -10 Degrees); Figure 5.68 Network to Determine Homogeneity

5.87
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Functions
Quadrilateral Phase-Distance Elements
Quadrilateral Phase Nonhomogeneous Setting (TANGP)
Nonhomogeneous negative-sequence networks can cause distance elements to
underreach or overreach. Use the network in Figure 5.68 to determine whether
the negative-sequence network is homogeneous. Z
LEFT
is the total impedance up
to the fault (F) on the left-hand side, while Z
RIGHT
is the total impedance up to
the fault on the right-hand side.
Figure 5.67 Quadrilateral Phase-Distance Element Characteristic (TANGP = –10 degrees)
Zone 3
TANGP = —10 degrees
Zone 2
Zone 1
Z1ANG
RP1
XP1
XP2
XP3
jX
—RP RP2 RP3
R
Figure 5.68 Network to Determine Homogeneity
IF
F
IF
Z
RIGHTZLEFT
Z1S m • Z1L (1 — m) • Z1L Z1R
SR