ABB RELION RET670 Applications Manual page 10

Table of contents
4
T-feeder protection..................................................................... 167
Tertiary reactor protection.......................................................... 170
Restricted earth fault protection (87N)........................................173
Alarm level operation..................................................................175
Low impedance restricted earth fault protection REFPDIF (87N).........176
Identification.................................................................................... 176
Application....................................................................................... 176
Transformer winding, solidly grounded.......................................177
Transformer winding, grounded through Zig-Zag grounding
transformer................................................................................. 178
Autotransformer winding, solidly grounded................................ 179
Reactor winding, solidly grounded..............................................180
Multi-breaker applications...........................................................181
CT grounding direction............................................................... 182
Setting guidelines............................................................................ 182
Setting and configuration............................................................182
Settings.......................................................................................183
Additional security logic for differential protection LDRGFC (11)......... 184
Identification.................................................................................... 184
Application....................................................................................... 184
Setting guidelines............................................................................ 186
Section 8 Impedance protection........................................................189
Distance measuring zone, quadrilateral characteristic for series
compensated lines ZMCPDIS (21), ZMCAPDIS (21), ZDSRDIR
(21D).....................................................................................................189
Identification.................................................................................... 189
Application....................................................................................... 189
Introduction.................................................................................189
System grounding.......................................................................190
Fault infeed from remote end..................................................... 192
Load encroachment....................................................................193
Long transmission line application..............................................194
Parallel line application with mutual coupling............................. 195
Tapped line application...............................................................203
Series compensation in power systems..................................... 205
Challenges in protection of series compensated and
adjacent power lines...................................................................214
Impact of series compensation on protective IED of
adjacent lines..............................................................................226
Distance protection.....................................................................227
Transformer protection RET670 2.2 ANSI
Application manual