ABB REG650 Technical Manual page 9

Technical Manual
Elimination of zero sequence currents.........................................89
Restrained and unrestrained limits of the differential
protection......................................................................................90
Fundamental frequency negative sequence differential
currents.........................................................................................93
Internal/external fault discriminator...............................................95
Unrestrained, and sensitive negative sequence protections........99
Instantaneous differential currents.............................................101
Harmonic and waveform block criteria.......................................101
Switch onto fault feature.............................................................102
Logic diagram.............................................................................103
Technical data.................................................................................110
1Ph High impedance differential protection HZPDIF (87).....................110
Identification....................................................................................110
Introduction......................................................................................111
Function block.................................................................................111
Signals.............................................................................................111
Settings............................................................................................112
Monitored data.................................................................................112
Operation principle..........................................................................112
Logic diagram.............................................................................112
Technical data.................................................................................113
Generator differential protection GENPDIF (87G)................................113
Identification....................................................................................114
Functionality....................................................................................114
Function block.................................................................................115
Signals.............................................................................................115
Settings............................................................................................116
Operation principle..........................................................................117
Function calculation principles....................................................119
Fundamental frequency differential currents..............................119
Supplementary criteria................................................................124
Harmonic restrain.......................................................................127
Cross-block logic scheme...........................................................127
Simplified block diagrams...........................................................128
Technical data.................................................................................130
Section 7 Impedance protection........................................................133
Underimpedance protection for generators and transformers
ZGCPDIS (21G)....................................................................................133
Identification....................................................................................133
Table of contents
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