Thytronic Pro-N NVA100X-D

APPENDIX
351
NVA100X-D - Manual - 02 - 2016
Directional ground overcurrent 67N - Moderately inverse time curve (ANSI/IEEE type MI)—
F_67N-ANSIMI-Char.ai
1.1
2 3 4 5 6 7 8 9 10 20
I
ED
/I
ED
>inv
0.01
0.1
1
10
100
1000
10000
t [s]
10 s
60 s
t
ED
>
inv
5 s
1 s
t
ED
>
inv
= 0.02 s
t
ED
>
inv
= 0.2 s
t
ED
>
inv
= 0.1 s
t
ED
>
inv
= 0.5 s
t =
t
ED
>
inv
·
[(I
ED
/I
ED
>
inv
)
0.02
-1]
0.01
+ 0.023
Note: match of operating and setting time takes place when I
ED
/I
ED
>
inv
= 1.664