4-26 Loss-of-Potential, Load Encroachment, and Directional Element Logic Date Code 20001006
SEL-351 Instruction Manual
DIRECTIONAL CONTROL SETTINGS
The directional control for overcurrent elements is enabled by making directional control enable
setting E32. Setting E32 has setting choices:
Y enable directional control
N disable directional control
AUTO enable directional control and set a number of the directional element settings
automatically
Note: If directional control enable setting E32 = N, directional control is disabled and no
directional control settings are made. All level direction settings are set internally as:
DIR1 = N (no directional control for Level 1 overcurrent elements)
DIR2 = N (no directional control for Level 2 overcurrent elements)
DIR3 = N (no directional control for Level 3 overcurrent elements)
DIR4 = N (no directional control for Level 4 overcurrent elements)
With the above settings, the directional control outputs in Figure 4.12, Figure 4.17, and
Figure 4.18 assert to logical 1. The referenced overcurrent elements in Figure 4.12,
Figure 4.17, and Figure 4.18 are then not controlled by the directional control logic.
Settings Made Automatically
If the directional control enable setting E32 is set:
E32 = AUTO
then the following directional control settings are calculated and set automatically:
Z2F, Z2R, 50QFP, 50QRP, a2, k2, 50GFP, 50GRP, a0, Z0F, and Z0R
Once these settings are calculated automatically, they can only be modified if the user goes back
and changes the directional control enable setting to E32 = Y.
The remaining directional control settings are not set automatically if setting E32 = AUTO. They
have to be set by the user, whether setting E32 = AUTO or Y. These settings are:
DIR1, DIR2, DIR3, DIR4, ORDER, 50P32P, and E32IV
All these settings are explained in detail in the remainder of this subsection.
Courtesy of NationalSwitchgear.com
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