4.18
SEL-311C Relay Instruction Manual Date Code 20060320
Loss-of-Potential, CCVT Transient Detection, Load-Encroachment, and Directional Element Logic
Directional Control for Phase Distance and Negative-Sequence Elements
Directional
Element Routing
Refer to Figure 4.13 and Figure 4.14.
The directional element outputs are routed to the forward (Relay Word bit
32QF) and reverse (Relay Word bit 32QR) logic points.
Loss-of-Potential
Note if both the following are true:
➤ Enable setting ELOP = Y
➤ A loss-of-potential condition occurs (Relay Word bit LOP
asserts)
then the forward logic points (Relay Word bit 32QF) assert to logical 1, thus
enabling elements that are set direction forward. These direction forward
elements effectively become nondirectional and provide protection during a
loss-of-potential condition.
Refer to Figure 4.1 and accompanying text for more information on loss-of-
potential.
As shown in Figure 3.4–Figure 3.6, ILOP also disables all phase and ground
distance elements.
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