Schweitzer Engineering Laboratories SEL-421-4 - Page 17

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Date Code 20171021 Instruction Manual SEL-421 Relay
List of Figures
Figure 4.22 Bay With Ground Switch (Option 8).........................................................................................4.22
Figure 4.23 Bay Without Ground Switch (Option 9)....................................................................................4.23
Figure 4.24 Bay With Ground Switch (Option 10).......................................................................................4.23
Figure 4.25 Bay Without Ground Switch (Option 11)..................................................................................4.24
Figure 4.26 Left Breaker Bay With Ground Switch (Option 12) .................................................................4.24
Figure 4.27 Right Breaker Bay With Ground Switch (Option 13) ...............................................................4.25
Figure 4.28 Middle Breaker Bay (Option 14)...............................................................................................4.25
Figure 4.29 Left Breaker Bay Without Ground Switch (Option 15) ............................................................4.26
Figure 4.30 Right Breaker Bay Without Ground Switch (Option 16) ..........................................................4.26
Figure 4.31 Bay With Ground Switch (Option 17).......................................................................................4.27
Figure 4.32 Bay Without Ground Switch (Option 18)..................................................................................4.27
Figure 4.33 Left Breaker Bay With Ground Switch (Option 19) .................................................................4.28
Figure 4.34 Left Breaker Bay Without Ground Switch (Option 20) ............................................................4.28
Figure 4.35 Right Breaker Bay With Ground Switch (Option 21) ...............................................................4.29
Figure 4.36 Right Breaker Bay Without Ground Switch (Option 22) ..........................................................4.29
Figure 4.37 Source Transfer (Option 23)......................................................................................................4.30
Figure 4.38 Throw-Over Bus Type 1 Switch (Option 24)............................................................................4.30
Figure 4.39 Throw-Over Bus Type 2 Switch (Option 25)............................................................................4.31
Figure 4.40 Screen 1 .....................................................................................................................................4.31
Figure 4.41 Screen 2 .....................................................................................................................................4.32
Figure 5.1 Current and Voltage Source Connections for the SEL-421 Relay ..............................................5.2
Figure 5.2 Main and Alternate Line-Current Source Assignments...............................................................5.3
Figure 5.3 Combined Currents for Line-Current Source Assignment ..........................................................5.3
Figure 5.4 Breaker Current Source Assignments..........................................................................................5.3
Figure 5.5 ESS := 1, Single Circuit Breaker Configuration..........................................................................5.8
Figure 5.6 ESS := 2, Single Circuit Breaker Configuration..........................................................................5.9
Figure 5.7 ESS := 3, Double Circuit Breaker Configuration......................................................................5.10
Figure 5.8 ESS := 4, Double Circuit Breaker Configuration......................................................................5.11
Figure 5.9 Tapped EHV Overhead Transmission Line...............................................................................5.12
Figure 5.10 ESS := Y, Tapped Line..............................................................................................................5.12
Figure 5.11 ESS := Y, Single Circuit Breaker With Current Polarizing Source Tapped Power
Transformer............................................................................................................................5.13
Figure 5.12 SEL-421 Alpha Quantity Calculation........................................................................................5.16
Figure 5.13 Undervoltage Supervision Logic ...............................................................................................5.18
Figure 5.14 Frequency Element Logic..........................................................................................................5.20
Figure 5.15 Sample TEC Command Response.............................................................................................5.22
Figure 5.16 Sample TEC n Command Response..........................................................................................5.22
Figure 5.17 Pole-Open Logic Diagram.........................................................................................................5.27
Figure 5.18 LOP Logic Process Overview ...................................................................................................5.30
Figure 5.19 LOP Logic .................................................................................................................................5.32
Figure 5.20 32Q and 32QG Enable Logic Diagram .....................................................................................5.38
Figure 5.21 32V and 32I Enable Logic Diagram..........................................................................................5.38
Figure 5.22 Best Choice Ground Directional Element Logic.......................................................................5.40
Figure 5.23 Negative-Sequence Voltage-Polarized Directional Element Logic ..........................................5.41
Figure 5.24 Zero-Sequence Voltage-Polarized Directional Element Logic .................................................5.41
Figure 5.25 Zero-Sequence Current-Polarized Directional Element Logic..................................................5.42
Figure 5.26 Ground Directional Element Output Logic Diagram ................................................................5.42
Figure 5.27 32P, Phase Directional Element Logic Diagram .......................................................................5.46
Figure 5.28 32Q, Negative-Sequence Directional Element Logic Diagram.................................................5.46
Figure 5.29 CVT Transient Detection Logic ................................................................................................5.48
Figure 5.30 Load-Encroachment Logic Diagram .........................................................................................5.49
Figure 5.31 Load-Encroachment Characteristics..........................................................................................5.50
Figure 5.32 OOS Characteristics ..................................................................................................................5.51
Figure 5.33 OOS Positive-Sequence Measurements ....................................................................................5.54
Figure 5.34 OOS Override Logic..................................................................................................................5.54
Figure 5.35 OOS Logic Diagram..................................................................................................................5.55