ABB Relion 670 series, Technical Reference Manual

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13.8.8.2 Principle of operation
Negative sequence overcurrent protection (LCNSPTOC, 46) is a definite time stage
comparator function. The negative sequence input current from the SMAI block is
connected as input to the function through a group connection I3P in PCM600. This
current is compared against the preset value and a pickup signal will be set high if the
input negative sequence current is greater than the preset value
Pickup2 . Trip signal
will be set high after a time delay setting of tI2 . BLOCK input will block the complete
function. BLKTR will block the trip output. The negative sequence current is available
as service value output I2.
13.8.8.3 Function block
ANSI09000769-1-en.vsd
LCNSPTOC (46)
I3P*
BLOCK
BLKTR TRIP
RI
ANSI09000769 V1 EN
Figure 423: LCNSPTOC (46) Function block
13.8.8.4 Input and output signals
Table 475: LCNSPTOC (46) Input signals
Name Type Default Description
I3P GROUP
SIGNAL
- Three phase group signal for current inputs
BLOCK BOOLEAN 0 Block overall function
BLKTR BOOLEAN 0 Block trip signal
Table 476: LCNSPTOC (46) Output signals
Name Type Description
TRIP BOOLEAN Trip signal negative sequence over current protection
RI BOOLEAN Start signal for negative sequence over current
protection
1MRK505222-UUS C
Section 13
Scheme communication
849
Technical reference manual