Setting Guidelines - ABB RELION 670 Series Applications Manual

Section 6
Differential protection
Phase-to-phase current variation takes the current samples (IL1–IL2, IL2–IL3, etc.) as input and
it calculates the variation using the sampling value based algorithm. Phase-to-phase current
variation function is major one to fulfil the objectives of the start up element.
Zero sequence criterion takes the zero sequence current as input. It increases security of
protection during the high impedance fault conditions.
Low voltage criterion takes the phase voltages and phase to phase voltages as inputs. It
increases the security of protection when the three phase fault occurred on the weak end side.
Low current criterion takes the phase currents as inputs and it increases the dependability
during the switch onto fault case of unloaded line.
The differential function can be allowed to trip as no load is fed through the line and
protection is not working correctly.
Features:
• Startup element is sensitive enough to detect the abnormal status of the protected
system
• Startup element does not influence the operation speed of main protection
• Startup element detects the evolving faults, high impedance faults and three phase fault
on weak side
• It is possible to block the each sub function of startup element
• Startup signal has a settable pulse time
The Additional security logic for differential protection LDRGFC is connected as a local
criterion to release the tripping from line differential protection. LDRGFC is connected with an
AND gate to the trip signals from LDLPDIF function. Figure
phase tripping, but LDRGFC can be configured with individual release to all phases trip. The
START signal can also, through one of the available binary signal transfer channels, be sent to
remote end and there connected to input REMSTUP. Normally, the local criterion is sufficient.
Start signal from
remote side
IEC11000232 V3 EN-US
Figure 69: Local release criterion configuration for line differential protection
6.4.3

Setting guidelines

GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ),
UBase ) and ( SBase ).
(
tStUpReset : Reset delay of the startup signal. The default value is recommended.
142
LDLPSCH
CTFAIL TRIP
OUTSERV TRL1
BLOCK TRL2
TRL3
TRLOCAL
TRLOCL1
TRLOCL2
TRLOCL3
TRREMOTE
DIFLBLKD
LDRGFC
I3P* START
U3P* STCVL1L2
BLOCK STCVL2L3
BLKCV STCVL3L1
BLKUC STUC
BLK3I0 ST3I0
BLKUV STUV
REMSTUP
69 shows a configuration for three
AND
INPUT1 OUT
INPUT2 NOUT
INPUT3
INPUT4N
Start signal to
remote side
IEC11000232-3-en.vsd
1MRK 505 343-UEN B
Release of line
differential
protection trip
GUID-3C315FA5-8262-416D-A8ED-927FE0BFAB8F v3
Application manual