Schweitzer Engineering Laboratories SEL-421-4 - Table 5.35 Ground Directional Element Enables

5.37
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Functions
Ground Directional Element
ORDER
The SEL-421 uses Best Choice Ground Directional Element logic to determine
the order in which the relay selects 32QG, 32V, or 32I to provide directional deci-
sions for the ground-distance elements and the residual ground directional over-
current elements. Directional element classification is as follows:
➤ Q—Negative-sequence voltage-polarized directional element (32QG)
➤ V—Zero-sequence voltage-polarized directional element (32V)
➤ I—Zero-sequence current-polarized directional element (32I)
You can set ORDER with any combination of Q, V, and I. The listed order of
these directional elements determines the priority that these elements operate to
provide the ground directional element.
Set E32 := Y to edit the ground directional element settings. If you set E32 := Y
the relay hides certain relay settings depending on the setting ORDER.
If ORDER does not contain Q, the relay hides the Z2F, Z2R, a2, and k2 settings.
If ORDER does not contain V, the relay hides the Z0F and Z0R settings. If
ORDER contains only Q, the relay hides settings a0, E32IV, Z0F, and Z0R.
E32IV
SELOGIC control equation setting E32IV must be asserted to enable the zero-
sequence voltage-polarized or zero-sequence current-polarized directional ele-
ments. This provides directional control of the ground-distance elements and
directional residual ground overcurrent elements.
Directional Element Enables
The Relay Word bits shown in Table 5.3 5 indicate when the relay has enabled the
ground directional element.
Figure 5.20 and Figure 5.21 correspond to Table 5.35.
Table 5.35 Ground Directional Element Enables
Name Description
32QE Negative-sequence voltage-polarized directional element enable—phase faults
32QGE Negative-sequence voltage-polarized directional element enable—ground faults
32VE Zero-sequence voltage-polarized directional element enable—ground faults
32IE Zero-sequence current-polarized directional element enable—ground faults