ABB RET650 Technical Manual page 10

Table of contents
4
Operation principle.................................................................... 125
Resistive reach in forward direction..................................... 126
Resistive reach in reverse direction..................................... 127
Reactive reach in forward and reverse direction.................. 128
Basic detection logic.............................................................128
Operating and inhibit conditions........................................... 130
Technical data........................................................................... 130
Underimpedance protection for generators and transformers
ZGCPDIS........................................................................................130
Identification.............................................................................. 130
Functionality.............................................................................. 131
Function block........................................................................... 131
Signals.......................................................................................132
Settings......................................................................................132
Operation principle.................................................................... 133
Full scheme measurement................................................... 133
Impedance characteristic..................................................... 133
Basic operation characteristics.............................................134
Theory of operation.............................................................. 135
Technical data........................................................................... 137
Load encroachment LEPDIS ......................................................... 137
Identification.............................................................................. 137
Functionality.............................................................................. 137
Function block........................................................................... 138
Signals.......................................................................................138
Settings......................................................................................138
Operation principle.................................................................... 138
Load encroachment..............................................................139
Simplified logic diagrams......................................................140
Technical data........................................................................... 140
Section 8 Current protection.........................................................141
Instantaneous phase overcurrent protection 3-phase output
PHPIOC .........................................................................................141
Identification ............................................................................. 141
Functionality.............................................................................. 141
Function block........................................................................... 141
Signals.......................................................................................141
Settings......................................................................................142
Monitored data...........................................................................142
Operation principle.................................................................... 142
Technical data........................................................................... 142
Four step phase overcurrent protection 3-phase output
OC4PTOC ..................................................................................... 143
Technical manual