FUNCTION CHARACTERISTICS
74
NA30 - Manual - 04 - 2022
0
T
RESET
t
E>
0
T
Fun_50N-51NS1.ai
t
>RES
T
0
≥
1
t
E>def
t
E>inv
t
E>RES
Start IE>
Trip IE>
CB-State
Start
I
2ndh>
ON
≡
Inhibit
(from IE>> and/or IE>>> residual overcurrent element)
ON
≡
Enable IE> residual overcurrent element
IE> inhibition
Block1, Block2, Block4
&
T
0
t
ECLP>
&
2nd harmonic restraint enable (ON
≡
Enable)
IE>2ndh-REST
IECLP>Mode
t
ECLP>
BF Enable (ON
≡
Enable)
IE>BF
towards BF logic
IE> BF
&
Trip IE>
TR
IP
PIN
G
M
AT
RIX
(
LE
D+R
EL
AY
S)
I
E
> Curve
A
B
C
A =“1”
A =“0 or OFF”
Output
t
ECLP>
IE> Enable
IE> residual overcurrent element (50N/51N) Block diagram
t
ECLP>
CB State
CB OPEN
CB CLOSED
CB OPEN
Output t
ECLP>
t
0.1 s
HIGH THRESHOLD/
BLOCK
LOW THRESHOLD/
UNBLOCK
HIGH THRESHOLD/
BLOCK
A = ON - Change setting
B = OFF
C = ON - Element blocking
I
E
>TR-K
I
E
>TR-L
I
E
>ST-L
I
E
>ST-K
≥
1
CLP I
E
>
I
E
≥
1
(Pickup within CLP)
(Pickup outside CLP)
I
ECLP>def
I
ECLP>inv
I
E
≥
I
ECLP
>
&
State
I
E
>
inv
I
E
≥
I
E
>
def
I
E
≥
I
E
>
inv
I
E
>
def
&
State
Residual overcurrent (50N/51N) - First element logic diagram (IE>)