Figure 39: Simplified forward fault 116
Figure 40: Mho expansion – forward fault 117
Figure 41: Simplified Reverse Fault 118
Figure 42: Mho contraction – reverse fault 119
Figure 43: Simplified quadrilateral characteristics 121
Figure 44: General Quadrilateral Characteristic Limits 122
Figure 45: Directional Quadrilateral Characteristic 123
Figure 46: Quadrilateral Characteristic featuring 2 directional forward zones and 1 offset zone 123
Figure 47: Five-sided polygon formed by Quadrilateral characteristic with Directional-Line
intersection of Reverse Impedance Reach Line
124
Figure 48: Impedance Reach line construction 126
Figure 49: Reverse impedance reach line construction 127
Figure 50: Resistive reach of phase elements 128
Figure 51: Resistive Reach line construction 128
Figure 52: Reverse resistive reach line construction 129
Figure 53: Phase Fault Quadrilateral characteristic summary 129
Figure 54: Impedance Reach line in Z1 plane 132
Figure 55: Impedance Reach line in ZLP plane 133
Figure 56: General characteristic in ZLP plane 134
Figure 57: Phase relations between I2 and Iph for leading and lagging polarizing currents 135
Figure 58: General characteristic in Z1 plane 136
Figure 59: Simplified characteristic in Z1 plane 137
Figure 60: Phase to phase current changes for C phase-to-ground (CN) fault 141
Figure 61: Biased Neutral Current Detector Characteristic 142
Figure 62: Load Blinder Characteristics 145
Figure 63: Sequence networks connection for an internal A-N fault 148
Figure 64: - DV Forward and Reverse tripping regions 149
Figure 65: Settings required to apply a quadrilateral zone 150
Figure 66: Settings required to apply a mho zone 151
Figure 67: Over-tilting effect 153
Figure 68: Example power system 158
Figure 69: Apparent Impedances seen by Distance Protection on a Teed Feeder 163
Figure 70: Scheme Assignment 169
Figure 71: Aided Distance PUR scheme 172
Figure 72: Aided Distance POR scheme 174
Figure 73: Example of fault current reversal of direction 176
Figure 74: Aided Distance Blocking scheme (BOP) 178
Figure 75: Aided Distance Send logic 180
Figure 76: Carrier Aided Schemes Receive logic 180
Figure 77: Aided Distance Tripping logic 181
Table of Figures P446SV
xxiv P446SV-TM-EN-1
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