Schweitzer Engineering Laboratories SEL-351 - Page 77

Date Code 20001006 Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements iii
SEL-351 Instruction Manual
Frequency Element Uses..................................................................................................3-55
Voltage Sag, Swell, and Interruption Elements (Available in Firmware Versions 3 and 4) ........3-56
Voltage Sag Elements:.....................................................................................................3-56
Voltage Swell Elements:..................................................................................................3-56
Voltage Interruption Elements: ........................................................................................3-57
Voltage Sag, Swell, and Interruption Elements Settings....................................................3-58
Power Elements (Available in Firmware Versions 2 and 4)......................................................3-58
Power Elements Settings .................................................................................................3-59
Accuracy ........................................................................................................................3-59
Power Elements Logic Operation.....................................................................................3-60
Power Elements Application - VAR Control for a Capacitor Bank...................................3-62
TABLES
Table 3.1: Available Phase Time-Overcurrent Elements...................................................................3-16
Table 3.2: Phase Time-Overcurrent Element (Maximum Phase) Settings..........................................3-17
Table 3.3: Phase Time-Overcurrent Element (Maximum Phase) Logic Outputs ................................3-18
Table 3.4: Neutral Ground Time-Overcurrent Element Settings........................................................3-25
Table 3.5: Residual Ground Time-Overcurrent Element Settings......................................................3-26
Table 3.6: Negative-Sequence Time-Overcurrent Element Settings...................................................3-28
Table 3.7: Voltage Values Used by Voltage Elements ......................................................................3-29
Table 3.8: Voltage Elements Settings and Settings Ranges (Wye-Connected Voltages) .....................3-30
Table 3.9: Voltage Elements Settings and Settings Ranges (Delta-Connected Voltages) ....................3-32
Table 3.10: Synchronism Check Elements Settings and Settings Ranges.............................................3-39
Table 3.11: Frequency Elements Settings and Settings Ranges ...........................................................3-53
Table 3.12: Sag/Swell/Interruption Elements Settings ........................................................................3-58
Table 3.13: Power Elements Settings and Settings Ranges .................................................................3-59
FIGURES
Figure 3.1: Levels 1 through 4 Phase Instantaneous Overcurrent Elements...........................................3-2
Figure 3.2: Levels 5 through 6 Phase Instantaneous Overcurrent Elements...........................................3-3
Figure 3.3: Levels 1 through 4 Phase Instantaneous/Definite-Time Overcurrent Elements (With
Directional Control Option)Directional Control Option................................................3-4
Figure 3.4: Combined Single-Phase Instantaneous Overcurrent Elements.............................................3-6
Figure 3.5: SEL-351 Relay Nondirectional Instantaneous Overcurrent Element Pickup Time
Curve.........................................................................................................................3-7
Figure 3.6: SEL-351 Relay Nondirectional Instantaneous Overcurrent Element Reset Time Curve.......3-7
Figure 3.7: Levels 1 Through 4 Phase-to-Phase Instantaneous Overcurrent Elements...........................3-9
Figure 3.8: Levels 1 Through 4 Neutral Ground Instantaneous/Definite-Time Overcurrent
Elements (With Directional Control Option)..............................................................3-10
Figure 3.9: Levels 5 Through 6 Neutral Ground Instantaneous Overcurrent Elements........................3-11
Figure 3.10: Levels 1 Through 4 Residual Ground Instantaneous/Definite-Time Overcurrent
Elements (With Directional Control Option)..............................................................3-12
Figure 3.11: Levels 5 Through 6 Residual Ground Instantaneous Overcurrent Elements ......................3-13
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