
vi L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
TABLE OF CONTENTS
5.6 FlexLogic........................................................................................................5-168
5.6.1 FlexLogic operands........................................................................................................ 5-168
5.6.2 FlexLogic rules.................................................................................................................. 5-184
5.6.3 FlexLogic evaluation...................................................................................................... 5-184
5.6.4 FlexLogic example..........................................................................................................5-185
5.6.5 FlexLogic equation editor............................................................................................ 5-190
5.6.6 FlexLogic timers............................................................................................................... 5-190
5.6.7 FlexElements ..................................................................................................................... 5-190
5.6.8 Non-volatile latches.......................................................................................................5-194
5.7 Grouped elements .......................................................................................5-196
5.7.1 Overview ............................................................................................................................. 5-196
5.7.2 Setting group 1................................................................................................................. 5-196
5.7.3 Line differential elements............................................................................................ 5-197
5.7.4 Line pickup ......................................................................................................................... 5-202
5.7.5 Distance............................................................................................................................... 5-204
5.7.6 Power swing detect (ANSI 68).................................................................................... 5-225
5.7.7 Load encroachment...................................................................................................... 5-234
5.7.8 Phase current ................................................................................................................... 5-235
5.7.9 Neutral current................................................................................................................. 5-247
5.7.10 Wattmetric ground fault.............................................................................................. 5-255
5.7.11 Ground current ................................................................................................................ 5-259
5.7.12 Negative sequence current........................................................................................ 5-266
5.7.13 Breaker failure (ANSI 50BF)......................................................................................... 5-272
5.7.14 Voltage elements ............................................................................................................ 5-282
5.7.15 Supervising elements.................................................................................................... 5-294
5.7.16 Sensitive directional power........................................................................................ 5-300
5.8 Control elements .........................................................................................5-303
5.8.1 Overview ............................................................................................................................. 5-303
5.8.2 Trip bus ................................................................................................................................ 5-303
5.8.3 Setting groups .................................................................................................................. 5-305
5.8.4 Selector switch................................................................................................................. 5-307
5.8.5 Trip output.......................................................................................................................... 5-313
5.8.6 Underfrequency (ANSI 81U)........................................................................................ 5-319
5.8.7 Overfrequency (ANSI 81O) .......................................................................................... 5-320
5.8.8 Synchrocheck (ANSI 25) ............................................................................................... 5-321
5.8.9 Digital elements............................................................................................................... 5-326
5.8.10 Digital counters................................................................................................................ 5-329
5.8.11 Monitoring elements ..................................................................................................... 5-331
5.8.12 Pilot schemes.................................................................................................................... 5-355
5.8.13 Autoreclose (ANSI 79).................................................................................................... 5-378
5.8.14 Frequency rate of change (ANSI 81R).................................................................... 5-391
5.9 Inputs/outputs .............................................................................................5-392
5.9.1 Contact inputs.................................................................................................................. 5-392
5.9.2 Virtual inputs..................................................................................................................... 5-394
5.9.3 Contact outputs............................................................................................................... 5-395
5.9.4 Virtual outputs.................................................................................................................. 5-399
5.9.5 Direct inputs and outputs ........................................................................................... 5-399
5.9.6 Resetting ............................................................................................................................. 5-400
5.10 Transducer inputs/outputs........................................................................5-401
5.10.1 DCmA inputs...................................................................................................................... 5-401
5.10.2 RTD inputs .......................................................................................................................... 5-402
5.10.3 DCmA outputs .................................................................................................................. 5-403
5.11 Testing ...........................................................................................................5-407
5.11.1 Test mode function ........................................................................................................5-407
5.11.2 Test mode forcing........................................................................................................... 5-407
5.11.3 Phasor Measurement Unit test values.................................................................. 5-408