Thytronic Pro-N NVA100X-D

APPENDIX
339
NVA100X-D - Manual - 02 - 2016
Ground directional overcurrent 67N(Comp) - Very inverse time curve (IEC 60255-3/BS142 type B)—
F_67N(Comp)-IECB-Char.ai
1.1
2 3 4 5 6 7 8 9 10 20
I
ECL
/I
EDC
>
inv
I
ECH
/I
EDC
>
inv
0.01
0.1
1
10
100
1000
10000
t [s]
10 s
60 s
5 s
1 s
0.5 s
0.2 s
0.02 s
0.1 s
Note: match of operating and setting time takes place when I
ECL
/I
EDC
>
inv
o I
ECH
/I
EDC
>
inv
= 14.5
t =
t
EDC
>
inv
t
EDC
>
inv
·
[(I
ECL
/I
EDC
>
inv
)-1]
13.5
t =
t
EDC
>
inv
·
[(I
ECH
/I
EDC
>
inv
)-1]
13.5