Schweitzer Engineering Laboratories SEL-421-4 - Page 18

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SEL-421 Relay Instruction Manual Date Code 20171021
List of Figures
Figure 5.36 Open-Pole OSB Unblock Logic ................................................................................................5.56
Figure 5.37 Zero-Setting OOS Blocking Function .......................................................................................5.56
Figure 5.38 Swing Center Voltage Slope Detection Logic...........................................................................5.58
Figure 5.39 Starter Zone Characteristic ........................................................................................................5.59
Figure 5.40 Swing Signature Detector Logic................................................................................................5.60
Figure 5.41 Swing Signature Detector Logic................................................................................................5.61
Figure 5.42 Reset Conditions Logic .............................................................................................................5.62
Figure 5.43 Type of Power Swings Detected by the DOSB Function..........................................................5.63
Figure 5.44 Dependable Power-Swing Block Detector Logic (EOOS = Y1) ..............................................5.64
Figure 5.45 Dependable Power-Swing Block Detector Logic (EOOS = Y) ................................................5.65
Figure 5.46 Relay Word Bit DOSB Is the OR Combination of DOSBY1 and DOSBY......................................5.65
Figure 5.47 Logic Diagram of the Three-Phase Fault Detector....................................................................5.66
Figure 5.48 Pole-Open OOS Blocking Logic ...............................................................................................5.66
Figure 5.49 I0/IA2 Angle Supervision During Pole-Open Situation............................................................5.67
Figure 5.50 Blocking of the MAG Signal by the OSBA Fault Detection ....................................................5.67
Figure 5.51 Unblocking of the MAB Signal by the 67QUB Element ..........................................................5.68
Figure 5.52 Directional Element Signals 67QUBF and 67QUBR................................................................5.68
Figure 5.53 OST Scheme Logic Resistive and Reactive Blinders................................................................5.69
Figure 5.54 Logic That Determines Positive-Sequence Impedance Trajectory (EOOS = Y1) ....................5.70
Figure 5.55 Out-of-Step Trip Logic (EOOS = Y1).......................................................................................5.71
Figure 5.56 Out-of-Step Blocking for Zone 1 Through Zone 5....................................................................5.72
Figure 5.57 Zone 1 Mho Ground-Distance Element Logic Diagram ...........................................................5.74
Figure 5.58 Zone 2 Mho Ground-Distance Element Logic Diagram ...........................................................5.75
Figure 5.59 Zones 3, 4, and 5 Mho Ground-Distance Element Logic Diagram...........................................5.76
Figure 5.60 Zone 1 Quadrilateral Ground-Distance Element Logic Diagram..............................................5.78
Figure 5.61 Zone 2 Quadrilateral Distance Element Logic Diagram ...........................................................5.79
Figure 5.62 Zones 3, 4, and 5 Quadrilateral Ground-Distance Element Logic ............................................5.80
Figure 5.63 Zone 1 Mho Phase-Distance Element Logic Diagram ..............................................................5.82
Figure 5.64 Zone 2 Mho Phase-Distance Element Logic Diagram ..............................................................5.83
Figure 5.65 Zones 3, 4, and 5 Mho Phase-Distance Element Logic Diagram..............................................5.84
Figure 5.66 Quadrilateral Phase-Distance Element Characteristic (TANGP = 0)........................................5.86
Figure 5.67 Quadrilateral Phase-Distance Element Characteristic (TANGP = –10 degrees) ......................5.87
Figure 5.68 Network to Determine Homogeneity ........................................................................................5.87
Figure 5.69 Tilt in Apparent Fault Impedance Resulting From Nonhomogeneity.......................................5.88
Figure 5.70 Zone 1 AB Loop Conventional Quadrilateral Phase-Distance Element Logic .........................5.90
Figure 5.71 Zone 2 AB Loop Conventional Quadrilateral Phase-Distance Element Logic .........................5.90
Figure 5.72 Zone 3, 4, and 5 AB Loop Conventional Quadrilateral Phase-Distance Element Logic ..........5.91
Figure 5.73 Zone Timers...............................................................................................................................5.93
Figure 5.74 Phase Instantaneous/Definite-Time Overcurrent Elements.......................................................5.97
Figure 5.75 Residual Ground Instantaneous/Directional Overcurrent Elements..........................................5.98
Figure 5.76 Negative-Sequence Instantaneous/Directional Overcurrent Elements..............................................5.99
Figure 5.77 U.S. Moderately Inverse—U1 .................................................................................................5.103
Figure 5.78 U.S. Inverse—U2 ....................................................................................................................5.104
Figure 5.79 U.S. Very Inverse—U3 ...........................................................................................................5.105
Figure 5.80 U.S. Extremely Inverse—U4...................................................................................................5.106
Figure 5.81 U.S. Short-Time Inverse—U5 .................................................................................................5.107
Figure 5.82 IEC Standard Inverse—C1 ......................................................................................................5.108
Figure 5.83 IEC Very Inverse—C2 ............................................................................................................5.109
Figure 5.84 IEC Extremely Inverse—C3....................................................................................................5.110
Figure 5.85 IEC Long-Time Inverse—C4 ..................................................................................................5.111
Figure 5.86 IEC Short-Time Inverse—C5..................................................................................................5.112
Figure 5.87 Selectable Inverse-Time Overcurrent Element Logic Diagram ..............................................5.113
Figure 5.88 Undervoltage Elements............................................................................................................5.113
Figure 5.89 Overvoltage Elements..............................................................................................................5.114
Figure 5.90 SOTF Logic Diagram ..............................................................................................................5.119
Figure 5.91 Required Zone Directional Settings ........................................................................................5.120