Thytronic Pro-N NVA100X-D - Directional Ground Overcurrent 67 N - very Inverse Time Curve (ANSI;IEEE Type VI)

352
NVA100X-D - Manual - 02 - 2016
APPENDIX
Directional ground overcurrent 67N - Very inverse time curve (ANSI/IEEE type VI)—
F_67N-ANSIVI-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
= 0.5 s
t
ED
>
inv
= 0.2 s
t
ED
>
inv
= 0.1 s
t
ED
>
inv
= 0.02 s
t =
t
ED
>
inv
·
[(I
ED
/I
ED
>
inv
)
2
-1]
3.922
+ 0.092
Note: match of operating and setting time takes place when I
ED
/I
ED
>
inv
= 2.306