Schweitzer Engineering SEL-351P, Quick Start Manual

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ii Loss-of-Potential, Load Encroachment, and Directional Element Logic Date Code 990430
SEL-351P Manual Técnico
50GFP – Forward Directional Residual Ground Current Pickup ...............................4-33
50GRP – Reverse Directional Residual Ground Current Pickup ...............................4-33
50GFP and 50GRP Set Automatically ................................................................4-33
a0 – Positive-Sequence Current Restraint Factor, I
0
/I
1
...............................................4-33
a0 Set Automatically ...........................................................................................4-33
Z0F – Forward Directional Z0 Threshold...................................................................4-34
Z0R – Reverse Directional Z0 Threshold ...................................................................4-34
Z0F and Z0R Set Automatically .........................................................................4-34
E32IV – SEL
OGIC
Control Equation Enable ......................................................................4-34
Directional Control Provided by Torque Control Settings.........................................................4-35
TABLES
Table 4.1: Overcurrent Elements Controlled by Level Direction Settings DIR1 through DIR4
(corresponding overcurrent element figure numbers in parentheses)..........................4-28
FIGURES
Figure 4.1: Loss-of-Potential Logic...........................................................................................................4-1
Figure 4.2: Load-Encroachment Logic ......................................................................................................4-3
Figure 4.3: Migration of Apparent Positive-Sequence Impedance for a Fault Condition.........................4-6
Figure 4.4: General Logic Flow of Directional Control for Neutral Ground and Residual Ground
Overcurrent Elements.....................................................................................................4-8
Figure 4.5: Internal Enables (32QE and 32QGE) Logic for Negative-Sequence Voltage-Polarized
Directional Elements....................................................................................................4-11
Figure 4.6: Internal Enable (32VE) Logic for Zero-Sequence Voltage-Polarized, Residual-
Current Directional Element ........................................................................................4-12
Figure 4.7: Internal Enable (32NE) for Zero-Sequence Voltage-Polarized, Neutral-Current
Directional Element .....................................................................................................4-12
Figure 4.8: Best Choice Ground Directional Logic ................................................................................4-13
Figure 4.9: Negative-Sequence Voltage-Polarized Directional Element for Neutral Ground and
Residual Ground Overcurrent Elements ......................................................................4-14
Figure 4.10: Zero-Sequence Voltage-Polarized, Residual-Current Directional Element for Neutral
Ground and Residual Ground Overcurrent Elements ..................................................4-15
Figure 4.11: Zero-Sequence Voltage-Polarized, Neutral-Current Directional Elements for Neutral
Ground Overcurrent Elements .....................................................................................4-16
Figure 4.12: Routing of Directional Elements to Residual Ground Overcurrent Elements ....................4-17
Figure 4.13: Routing of Directional Elements to Neutral Ground Overcurrent Elements ......................4-17
Figure 4.14: Direction Forward/Reverse Logic for Residual Ground Overcurrent Elements.................4-18
Figure 4.15: Direction Forward/Reverse Logic for Neutral Ground Overcurrent Elements...................4-19
Figure 4.16: General Logic Flow of Directional Control for Negative-Sequence and Phase
Overcurrent Elements...................................................................................................4-20
Figure 4.17: Negative-Sequence Voltage-Polarized Directional Element for Negative-Sequence
and Phase Overcurrent Elements .................................................................................4-23
Figure 4.18: Positive-Sequence Voltage-Polarized Directional Element for Phase Overcurrent
Elements.......................................................................................................................4-24
Figure 4.19: Routing of Directional Elements to Negative-Sequence and Phase Overcurrent
Elements.......................................................................................................................4-25