ABB Relion 670 series, Technical Reference Manual, Page: 859 / 1232

Features:
• Phase wise pickup and trip signals
• Overcurrent protection
• Phase wise RMS current is available as service values
• Single definite time stage trip function.
13.8.10.2 Principle of operation
Three phase overcurrent (LCP3PTOC, 51) is used for detecting over current
conditions. LCP3PTOC (51) pickups when the current exceeds the set limit
PU 51 . It
operates with definite time (DT) characteristics, that is, the function operates after a
predefined time
tOC and resets when the fault current disappears. The function
contains a blocking functionality. It is possible to block the function output, timer or
the function itself, if desired.
13.8.10.3 Function block
ANSI09000771-1-en.vsd
LCP3PTOC (51)
I3P*
BLOCK
BLKTR TRIP
TR_A
TR_B
TR_C
RI
PU_A
PU_B
BFI_C
ANSI09000771 V1 EN
Figure 425: LCP3PTOC (51) Function block
13.8.10.4 Input and output signals
Table 483: LCP3PTOC (51) Input signals
Name Type Default Description
I3P GROUP
SIGNAL
- Three phase group signal for current inputs
BLOCK BOOLEAN 0 Block all binary outputs by resetting timers
BLKTR BOOLEAN 0 Block trip of the function
1MRK505222-UUS C
Section 13
Scheme communication
853
Technical reference manual