5. Functions
5.1. Functions included in AQ-F255
This chapter presents the functions of AQ-F255 Feeder Protection relay. AQ-F255 includes following
functions and amounts of instances of the functions.
Table. 5.1. - 1. Protection functions of AQ-F255
Name
IEC
ANSI
Description
NOC1
NOC2
NOC3
NOC4
I>
I>>
I>>>
I>>>>
50/51
Overcurrent protection (4 stages)
NEF1
NEF2
NEF3
NEF4
I0>
I0>>
I0>>>
I0>>>>
50N/51N
Residual overcurrent protection (4 stages)
DOC1
DOC2
DOC3
DOC4
IDir>
IDir>>
IDir>>>
IDir>>>>
67
Directional overcurrent protection (4 stages)
DEF1
DEF2
DEF3
DEF4
I0Dir>
I0Dir>>
I0Dir>>>
I0Dir>>>>
67N
Directional residual overcurrent protection (4 stages)
IEF1
I0Int>
67NT
Intermittent earth fault
CUB1
CUB2
CUB3
CUB4
I2>
I2>>
I2>>>
I2>>>>
46/46R/46L
Negative sequence overcurrent / phase current reversal / unbalance
protection (4 stages)
HOC1
HOC2
HOC3
HOC4
Ih>
Ih>>
Ih>>>
Ih>>>>
50h/51h/68h
Detection and blocking or tripping from selectable 2nd, 3rd, 4th, 5th, 7th,
9th, 11th, 13th, 15th, 17th, 19th harmonic. Phase currents and residual
currents separate stages. (4 stages)
CBF1
CBFP
50BF/52BF
Breaker failure protection
REF1
I0d>
87N
Low or high impedance restricted earth fault, cable end differential
protection
TOLF1
TF>
49L
Feeder thermal overload protection
OV1
OV2
OV3
OV4
U>
U>>
U>>>
U>>>>
59
Overvoltage protection (4 stages)
UV1
UV2
UV3
UV4
U<
U<<
U<<<
U<<<<
27
Undervoltage protections (4 stages)
VUB1
VUB2
VUB3
VUB4
U1&U2>/<
U1&U2>>/<<
U1&U2>>>/<<<
U1&U2>>>>/<<<<
59P/27P/47
Sequence voltage protection (4 stages)
NOV1
NOV2
NOV3
NOV4
U0>
U0>>
U0>>>
U0>>>>
59N
Neutral voltage protection (4 stages)
OPW1
P>
32O
Over power
UPW1
P<
32U
Under power
RPW1
Pr
32R
Reverse power
AQ-F255
Instruction manual
Version: 2.00
11
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