APPENDIX
185
NA30 - Manual - 04 - 2022
Residual overcurrent 50N/51N - Electromechanical inverse curves (EM)
F_51N-EM-Char.ai
1.1
2
3
4
5
6 7 8 9 10
20
I
E
/
I
E
>inv
0.01
0.1
1
10
100
1000
10000
t
[s]
t
E
>
inv
= 60 s
t
E
>
inv
= 10 s
t
E
>
inv
= 5 s
t
E
>
inv
= 1 s
t
E
>
inv
= 0.5 s
t
E
>
inv
= 0.2 s
t
E
>
inv
= 0.1 s
t
E
>
inv
= 0.02 s
Note: match of operating and setting time takes place when I
E
/I
E
>
inv
= 4
t
=
t
E
>
inv
·
[-0.236
·
(
I
E
/
I
E
>
inv
)
-1
+ 0.339]
0.28
