4-30 Loss-of-Potential, Load Encroachment, and Directional Element Logic Date Code 990430
SEL-351P Manual Técnico
If setting:
ORDER = OFF
then the two directional elements (Q and V) are inoperable. Note in
Figure SECTION 4: .14 and
Figure SECTION 4: .15 that setting ORDER = OFF effectively makes the neutral ground and
residual ground overcurrent elements nondirectional (the directional control outputs of
Figure SECTION 4: .14 and Figure SECTION 4: .15 are continuously asserted to logical 1).
50P32P – Phase Directional Element Three-Phase Current Pickup
Setting Range:
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 SECTION 4: .18).
If the load-encroachment logic is enabled (enable setting ELOAD = Y), then setting 50P32P is
not made or displayed, but is fixed internally at:
0.1 A secondary (1 A nominal phase current inputs, IA, IB, IC)
Z2F – Forward Directional Z2 Threshold
Z2R – Reverse Directional Z2 Threshold
Setting Range:
-320.00 to 320.00 Ω secondary (1 A nominal phase current inputs, IA, IB, IC)
Z2F and Z2R are used to calculate the Forward and Reverse Thresholds, respectively, for the
negative-sequence voltage-polarized directional elements (see
Figure SECTION 4: .9 and
Figure SECTION 4: .17).
Z2F and Z2R Set Automatically
If enable setting E32 = AUTO, settings Z2F and Z2R (negative-sequence impedance values) are
calculated automatically, using the positive-sequence line impedance magnitude setting Z1MAG
as follows:
Z2F = Z1MAG/2 (Ω secondary)
Z2R = Z1MAG/2 + 0.5 (Ω secondary)
If enable setting E32 = Y, settings Z2F and Z2R (negative-sequence impedance values) are
calculated by the user and entered by the user, but setting Z2R must be at least 0.5 Ω secondary
greater in value than setting Z2F.
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