FUNCTION CHARACTERISTICS
38
NC020 - Manual - 05 - 2022
Breaker failure (BF)
The elements (
I
>) can produce the Breaker Failure output if the
Trip I>
output is set for
BF Enable.
The outputs are available inside the
Set \ Breaker failure
menu.
[1]
Cold load pickup
If the CLP function (Cold Load Pick-up) is enabled for element blocking, the selected threshold may
be blocked for an adjustable time interval, starting from the circuit breaker closure.
This operating mode may be select by setting
ON-Blocking
the
ICLP>
parameter.
If the CLP function (Cold Load Pick-up) is enabled for threshold change, the selected threshold may
be changed for an adjustable time interval, starting from the circuit breaker closure.
This operating mode may be select by setting
ON-Changing
the
ICLP>
parameter, whereas the
operating thresholds within the CLP may be adjusted inside the
Set \ 50/51 RMS \
I> Element \ I>
Setpoint
menu.
For both operating modes the CLP Activation time parameters (
tCLP>
) may be adjusted inside the
Set \ 50/51 RMS \
I> Element \ I> Setpoint
menu.
Note 1 The common settings concerning the Breaker failure protection are adjustable inside the
Breaker Failure - BF
menu.
Fun_50-51-RMS.ai
I
L1RMS
I
L2RMS
I
L3RMS
t
I
>
RES
T
0
RESET
t
I
>
0
T
≥
1
≥
1
t
I
>
def
t
I
>
inv
t
I
>
RES
Start I>
Trip I>
CB-State
ON
≡
Enable I> overcurrent element
(Pickup within CLP)
(Pickup outside CLP)
&
T
0
t
CLP>
ICLP>Mode
I
CLP>def
t
CLP>
I
CLP>inv
ON
≡
Enable
BF Enable
towards BF logic
I> BF
&
Trip I>
TR
IP
PIN
G
M
AT
RIX
(
LE
D+R
EL
AY
S)
I
> Curve
0
T
A
B
C
A =“1”
A =“0 or OFF”
Output
t
CLP>
I> Enable
t
CLP>
CB State
CB OPEN
CB CLOSED
CB OPEN
Output t
CLP>
t
0.1 s
HIGH THRESHOLD/
BLOCK
LOW THRESHOLD/
UNBLOCK
HIGH THRESHOLD/
BLOCK
A = ON - Change setting
B = OFF
C = ON - Element blocking
I>TR-K
I>TR-L
I>ST-L
I>ST-K
&
State
I
>
inv
I
L1RMS
≥
I
>
def
I
L1RMS
≥
I
>
inv
I
L1RMS
≥
I
CLP
>
(def/inv)
I
>
def
&
State
RMS phase overcurrent (50/51 RMS) - First element logic diagram (I>)
