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5 Functions
5.1 Functions included in AQ-C255
The AQ-C255 capacitor bank protection IED includes the following functions as well as the number of
stages for those functions.
Table. 5.1 - 2. Protection functions of AQ-C255.
Name (number
of stages)
IEC
ANSI
Description
CPB (1)
-
-
Capacitor bank module
COL (2)
Icol>
Icol>>
49OL
Capacitor bank overload protection
CNU (1)
Cnu>
50UB
Capacitor bank neutral unbalance protection
UCP (1)
Iuc>
46C
Capacitor bank current unbalance protection
NOC (4)
I>
I>>
I>>>
I>>>>
50/51
Non-directional overcurrent protection
DOC (4)
Idir>
Idir>>
Idir>>>
Idir>>>>
67
Directional overcurrent protection
NEF (4)
I0>
I0>>
I0>>>
I0>>>>
50N/51N
Non-directional earth fault protection
DEF (4)
I0dir>
I0dir>>
I0dir>>>
I0dir>>>>
67N/32N
Directional earth fault protection
CUB (4)
I2>
I2>>
I2>>>
I2>>>>
46/46R/46L
Negative sequence overcurrent/
phase current reversal/
current unbalance protection
HOC (4)
Ih>
Ih>>
Ih>>>
Ih>>>>
50H/51H/68H
Harmonic overcurrent protection
The detection and blocking or tripping based on a
selectable harmonic. The phase currents and the residual
currents have separate stages.
NUC (1)
I<
46C
Non-directional undercurrent protection
IEF (1)
I0int>
67NT
Intermittent earth fault protection
CBFP (1)
CBFP
50BF/51BF
Circuit breaker failure protection
PQS (4)
P, Q, S>/<
P, Q, S>>/<<
P, Q, S>>>/<<<
P, Q, S>>>>/<<<<
32
Power protection
OPW (1)
P>
32O
Overpower protection
UPW (1)
P<
32U
Underpower protection
RPW (1)
Pr
32R
Reverse power protection
A
AQ
Q-C255
-C255
Instruction manual
Version: 2.06
© Arcteq Relays Ltd
IM00035
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