ABB ret650 - Page 9

Typical main CT connections for transformer differential
protection................................................................................85
Application Examples............................................................. 86
Summary and conclusions..................................................... 91
Low impedance restricted earth fault protection REFPDIF ............. 93
Identification................................................................................ 93
Application................................................................................... 93
Transformer winding, solidly earthed..................................... 94
Transformer winding, earthed through zig-zag earthing
transformer............................................................................. 94
Autotransformer winding, solidly earthed............................... 95
Reactor winding, solidly earthed............................................ 96
Multi-breaker applications...................................................... 97
CT earthing direction.............................................................. 98
Setting guidelines........................................................................ 98
Setting and configuration........................................................98
Settings.................................................................................. 99
Section 7 Current protection.........................................................101
Instantaneous phase overcurrent protection PHPIOC .................. 101
Identification.............................................................................. 101
Application................................................................................. 101
Setting guidelines...................................................................... 102
Meshed network without parallel line................................... 102
Meshed network with parallel line........................................ 104
Directional phase overcurrent protection, four steps OC4PTOC....106
Identification.............................................................................. 106
Application................................................................................. 106
Setting guidelines...................................................................... 107
Settings for each step...........................................................109
Setting example....................................................................112
Instantaneous residual overcurrent protection EFPIOC ................ 117
Identification.............................................................................. 117
Application................................................................................. 117
Setting guidelines...................................................................... 117
Directional residual overcurrent protection, four steps EF4PTOC .120
Identification.............................................................................. 120
Application................................................................................. 120
Setting guidelines...................................................................... 122
Common settings for all steps.............................................. 123
2nd harmonic restrain...........................................................124
Parallel transformer inrush current logic...............................125
Switch onto fault logic...........................................................126
Settings for each step (x = 1, 2, 3 and 4)............................. 127
Table of contents
Transformer protection RET650 2.2 IEC 3
Application manual