Sel 411L - Table 3.75 Ground Directional Element Settings AUTO Calculations

P.3.143
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
Ground Directional Element
If you set E32 to AUTO, the relay automatically calculates the settings shown
in Table 3.75.
Detailed Settings Description
If you set E32 to Y, you can change the settings listed in Table 3.75.
50FP and 50RP
Setting 50FP is the threshold for the current level detector that enables
forward decisions for both the negative- and zero-sequence voltage-polarized
directional elements. If the magnitude of 3I
2
or 3I
0
is greater than 50FP, the
corresponding directional element can process a forward decision.
Setting 50RP is the threshold for the current level detector that enables reverse
decisions for both the negative- and zero-sequence voltage-polarized
directional elements. If the magnitude of 3I
2
or 3I
0
is greater than 50RP, the
corresponding directional element can process a reverse decision.
Z2F and Z2R
Setting Z2F is the forward threshold for the negative-sequence voltage-
polarized directional element. If the relay measures the apparent negative-
sequence impedance z2 less than Z2F, the relay declares the unbalanced fault
to be forward.
50FP Forward directional overcurrent pickup (A) (0.05–1) • I
NOM
0.60
50RP Reverse directional overcurrent pickup (A) (0.05–1) • I
NOM
0.40
Z2F Forward directional Z2 threshold () 320/I
NOM
3.90
Z2R Reverse directional Z2 threshold () 320/I
NOM
4.00
a2 Positive-sequence restraint factor, I2/I1 0.02–0.5 0.10
k2 Zero-sequence restraint factor, I2/I0 0.1–1.2 0.20
Z0F Forward directional Z0 threshold () 320/I
NOM
12.40
Z0R Reverse directional Z2 threshold () 320/I
NOM
12.50
a0 Positive-sequence restraint factor, I0/I1 0.02–0.5 0.10
E32IV Zero-sequence voltage current enable SELOGIC equation 1
Table 3.75 Ground Directional Element Settings AUTO Calculations
Setting Equation
50FP 0.12 • I
NOM
50RP 0.08 • I
NOM
Z2F 0.5 • Z1MAG
Z2R Z2F + 1/(2 • I
NOM
)
a2 0.1
k2 0.2
Z0F 0.5 • Z0MAG
Z0R Z0F + 1/(2 • I
NOM
)
a0 0.1
Table 3.74 Ground Directional Element Settings (Sheet 2 of 2)
Setting Description Range
Default
(5 A)