ABB RELION 650 SERIES, Technical Manual

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possibility to detect earth faults. In addition, in low impedance earthed
networks, the inverse time characteristic gives better time-selectivity in case of
high zero-resistive fault currents.
Phase
currents
Phase-
ground
voltages
IN
UN
IEC13000013-1-en.vsd
IEC13000013 V1 EN-US
Figure 102: Connection of SDEPSDE to analog preprocessing function block
Overcurrent functionality uses true 3I0, i.e. sum of GRPxL1, GRPxL2 and
GRPxL3. For 3I0 to be calculated, connection is needed to all three phase inputs.
Directional and power functionality uses IN and UN. If a connection is made to
GRPxN this signal is used, else if connection is made to all inputs GRPxL1,
GRPxL2 and GRPxL3 the internally calculated sum of these inputs (3I0 and 3U0)
will be used.
7.6.3 Function block
SEMOD172780-4 v6
IEC07000032-2-en.vsd
SDEPSDE
I3P*
U3P*
BLOCK
BLKTR
BLKTRDIR
BLKNDN
BLKUN TRIP
TRDIRIN
TRNDIN
TRUN
START
STDIRIN
STNDIN
STUN
STFW
STRV
STDIR
UNREL
IEC07000032 V2 EN-US
Figure 103: SDEPSDE function block
1MRK 506 382-UEN A
Section 7
Current protection
Line distance protection REL650 2.2 IEC 219
Technical manual