Figure 39: Typical overflux current waveform 106
Figure 40: CT parameter mismatch logic diagram 109
Figure 41: Transformer biased tripping characteristic 111
Figure 42: Transient bias characteristic 113
Figure 43: Time to saturation - external AN fault 114
Figure 44: Effect of CTS restrain 115
Figure 45: Bias characteristic with circuitry fail alarm 115
Figure 46: Differential biased trip logic 116
Figure 47: 2nd harmonic blocking process 117
Figure 48: 2nd harmonic blocking logic 118
Figure 49: 5th harmonic blocking process 119
Figure 50: Differential protection blocking mechanisms 120
Figure 51: Triple slope characteristic 122
Figure 52: P642 used to protect a two winding transformer 122
Figure 53: P645 used to protect an autotransformer with loaded delta winding 125
Figure 54: P643 used to protect an autotransformer with unloaded delta winding 128
Figure 55: Unloaded delta – current distribution 129
Figure 56: Single bus differential protection zone 131
Figure 57: Busbar biased differential protection 133
Figure 58: Shunt Reactor single line diagram 134
Figure 59: P643 Using spare CT input for overcurrent protection 136
Figure 60: Stub Bus arrangement 137
Figure 61: Stub Bus Scheme Logic 138
Figure 62: Transformer losses 144
Figure 63: Through-fault alarm logic 155
Figure 64: P645 used to protect an autotransformer with loaded delta winding 156
Figure 65: Connection for RTD thermal probes 157
Figure 66: RTD logic 158
Figure 67: Current loop input ranges 160
Figure 68: Current Loop Input logic 161
Figure 69: Current Loop Output ranges 162
Figure 70: REF protection for delta side 168
Figure 71: REF protection for star side 168
Figure 72: REF Protection for resistance-earthed systems 169
Figure 73: REF Protection for solidly earthed system 169
Figure 74: Low Impedance REF Connection 171
Figure 75: Three-slope REF bias characteristic 171
Figure 76: High Impedance REF principle 172
Figure 77: High Impedance REF Connection 172
Figure 78: REF bias characteristic 174
Table of Figures P64x
xviii P64x-TM-EN-1.3
To Next Page
Loading...
