Date Code 20001006 Loss-of-Potential, Load Encroachment, and Directional Element Logic 4-29
SEL-351 Instruction Manual
Another example, if setting:
ORDER = V
then the zero-sequence voltage-polarized directional element (V = zero-sequence voltage-polarized
directional element; see Figure 4.9) provides directional control for the neutral ground and residual
ground overcurrent elements all the time.
Setting ORDER can be set with any element combination (e.g., ORDER = IQV, ORDER = QVI,
ORDER = IV, ORDER = VQ, ORDER = I, ORDER = Q).
If setting:
ORDER = OFF
then the three directional elements (Q, V, and I) are inoperable. Note in Figure 4.12 that setting
ORDER = OFF effectively makes the neutral ground and residual ground overcurrent elements
nondirectional (the directional control outputs of Figure 4.12 are continuously asserted to
logical 1).
50P32P – Phase Directional Element Three-Phase Current Pickup
Setting Range:
0.50 - 10.00 A secondary (5 A nominal phase current inputs, IA, IB, IC)
0.1 - 2.00 A secondary (1 A nominal phase current inputs, IA, IB, IC)
The 50P32P setting is set to pick up for all three-phase faults that need to be covered by the phase
overcurrent elements. It supervises the positive-sequence voltage-polarized directional elements
F32P and R32P (see Figure 4.15).
If the load-encroachment logic is enabled (enable setting ELOAD = Y), then setting 50P32P is not
made or displayed, but is fixed internally at:
0.5 A secondary (5 A nominal phase current inputs, IA, IB, IC)
0.1 A secondary (1 A nominal phase current inputs, IA, IB, IC)
Z2F – Forward Directional Z2 Threshold
Z2R – Reverse Directional Z2 Threshold
Setting Range:
-64.00 to 64.00 W secondary (150 V voltage inputs, VA, VB, VC; 5 A nominal phase current
inputs, IA, IB, IC)
-320.00 to 320.00 W secondary (150 V voltage inputs, VA, VB, VC; 1 A nominal phase
current inputs, IA, IB, IC)
Courtesy of NationalSwitchgear.com
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