Schweitzer Engineering Laboratories SEL-351-5, Instruction Manual

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viii List of Figures
SEL-351-5, -6, -7 Relay Instruction Manual
Date Code 20070117
Figure 3.3 Levels 1 Through 4 Phase Instantaneous/Definite-Time Overcurrent Elements
(With Directional Control Option)......................................................................................3.4
Figure 3.4 Combined Single-Phase Instantaneous Overcurrent Elements...............................................3.6
Figure 3.5 Nondirectional Instantaneous Overcurrent Element Pickup Time Curve...............................3.6
Figure 3.6 Nondirectional Instantaneous Overcurrent Element Reset Time Curve.................................3.7
Figure 3.7 Levels 1 Through 4 Phase-to-Phase Instantaneous Overcurrent Elements ............................3.8
Figure 3.8 Levels 1 Through 4 Neutral Ground Instantaneous/Definite-Time Overcurrent
Elements (With Directional Control Option) ......................................................................3.9
Figure 3.9 Levels 5 Through 6 Neutral Ground Instantaneous Overcurrent Elements............................3.9
Figure 3.10 Levels 1 Through 4 Residual Ground Instantaneous/Definite-Time Overcurrent
Elements (With Directional Control Option) ....................................................................3.11
Figure 3.11 Levels 5 Through 6 Residual Ground Instantaneous Overcurrent Elements........................3.11
Figure 3.12 Levels 1 Through 4 Negative-Sequence Instantaneous/Definite-Time Overcurrent
Elements (With Directional Control Option) ....................................................................3.14
Figure 3.13 Levels 5 Through 6 Negative-Sequence Instantaneous Overcurrent Elements ....................3.14
Figure 3.14 Phase Time-Overcurrent Element 51PT (With Directional Control Option) .......................3.16
Figure 3.15 A-Phase Time-Overcurrent Element 51AT (With Directional Control Option)...................3.19
Figure 3.16 B-Phase Time-Overcurrent Element 51BT (With Directional Control Option)...................3.20
Figure 3.17 C-Phase Time-Overcurrent Element 51CT (With Directional Control Option)...................3.20
Figure 3.18 Neutral Ground Time-Overcurrent Element 51NT (With Directional Control Option).......3.21
Figure 3.19 Residual Ground Time-Overcurrent Element 51GT (With Directional Control Option).....3.22
Figure 3.20 Negative-Sequence Time-Overcurrent Element 51QT (With Directional Control Option) .3.23
Figure 3.21 Single-Phase and Three-Phase Voltage Elements (Wye-Connected PTs) ............................3.28
Figure 3.22 Phase-to-Phase and Sequence Voltage Elements (Wye-Connected PTs) .............................3.29
Figure 3.23 Phase-to-Phase Voltage Elements (Delta-Connected PTs)...................................................3.30
Figure 3.24 Sequence Voltage Elements (Delta-Connected PTs) ............................................................3.30
Figure 3.25 Channel VS Voltage Elements (Wye- or Delta-Connected PTs) ..........................................3.31
Figure 3.26 Synchronism Check Voltage Window and Slip Frequency Elements ..................................3.36
Figure 3.27 Synchronism Check Elements ..............................................................................................3.37
Figure 3.28 Angle Difference Between V
P
and V
S
Compensated by Breaker Close Time
(f
P
< f
S
and V
P
Shown as Reference in This Example) ....................................................3.42
Figure 3.29 Undervoltage Block for Frequency Elements (Group Setting VNOM
≠
OFF)....................3.46
Figure 3.30 Undervoltage Block for Frequency Elements (Group Setting VNOM = OFF)....................3.46
Figure 3.31 Levels 1 Through 6 Frequency Elements .............................................................................3.47
Figure 3.32 Voltage Sag Elements ...........................................................................................................3.51
Figure 3.33 Voltage Swell Elements ........................................................................................................3.52
Figure 3.34 Voltage Interruption Elements ..............................................................................................3.52
Figure 3.35 Vbase Tracking Example (Three-Phase Disturbance, Wye Connected) ..............................3.54
Figure 3.36 Single-Phase Power Elements Logic (+VARS Example Shown).........................................3.59
Figure 3.37 Three-Phase Power Elements Logic .....................................................................................3.60
Figure 3.38 Power Elements Operation in the Real/Reactive Power Plane .............................................3.60
Figure 3.39 SEL-351(B) Provides VAR Control for 9600 kVAR Capacitor Bank ..................................3.61
Figure 3.40 Per Unit Setting Limits for Switching 9600 kVAR Capacitor Bank On- and Off-Line .......3.63
Figure 4.1 Loss-of-Potential Logic ..........................................................................................................4.1
Figure 4.2 Load-Encroachment Logic .....................................................................................................4.4
Figure 4.3 Migration of Apparent Positive-Sequence Impedance for a Fault Condition.........................4.7
Figure 4.4 General Logic Flow of Directional Control for Neutral Ground and Residual Ground
Overcurrent Elements (Excluding Ungrounded/High-Impedance Grounded Systems) ...4.10
Figure 4.5 General Logic Flow of Directional Control for Neutral Ground and Residual Ground
Overcurrent Elements (Ungrounded/High-Impedance Grounded Systems;
ORDER = U).....................................................................................................................4.11
Figure 4.6 Internal Enables (32QE and 32QGE) Logic for Negative-Sequence
Voltage-Polarized Directional Elements ...........................................................................4.18
Figure 4.7 Internal Enables (32VE and 32IE) Logic for Zero-Sequence Voltage-Polarized
and Channel IN Current-Polarized Directional Elements.................................................4.19
Figure 4.8 Internal Enable (32NE) Logic for Zero-Sequence Voltage-Polarized Directional
Elements (Low-Impedance Grounded, Petersen Coil-Grounded,
and Ungrounded/High-Impedance Grounded Systems) ...................................................4.20