Siemens SIPROTEC 7SJ62 Instruction Manual page 435

100
t [s]
30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
0.05
1 2 3


t = --------------------------- -

VERY INVERSE
(

100
t [s]
30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
0.05
1 2 3
DEFINITE INVERSE
t
Figure 10-3 Trip Characteristics Of The Inverse-time Overcurrent Protection, As Per ANSI/IEEE (Phases And Ground)
7SJ62 Manual
C53000-G1140-C121-1
D [s]
15
10
5
2
1
0.5
5 10 20
I/I
p

3.922

⋅
0.0982 [s]
+ D

2
⁄ )

I I p 1
–
D [s]
15
10
5
2
1
0.5
5 10 20
I/I
p
 
0.4797
 
+
0.21359
------------------------------------------ -
=
 
1.5625
( ⁄ )
 
I I 1
–
p
100
t [s]
30
20
10
5
3
2
1
0.5
0.3
0.2
0.1
0.05
1 2
EXTREMELY INVERSE
t =Trip time in seconds
D =Setting value of the time multiplier
I =Fault Current
I =Setting value of the pickup current
p
⋅
[s]
D
Technical Data
D [s]
15
10
5
2
0.5
1
3 5 20
10
I/I
p

5.64

0.02434
t
= --------------------------- - +

2
( ⁄ )

I I 1
–
p


⋅
D
[s]


10-17