NHP TemBreak PRO - Adjusting tr (Time Delay)

Protection Settings
Long Time Delay (LTD) protection
30
TemBreak PRO B_BE-UM-001-EN  V1.1.0
Adjusting t
r
(Time Delay)
The t
r
time delay defines the trip time of the long-time delay protection at a referenced current, either as a fixed value or as a multiple of I
r
.
The t
r
time delay can only be adjusted by selecting a pre-defined curve. The time to trip at any given current is calculated using the below formulae, where k
is a constant specific to each of the pre-defined curve settings.
The derivation of the constant k is given by the below formulae, where t
r
and I are reference values depending on the MCCB model and trip unit, and the
curve selected.
For all models and standard curves:





󰇧
  󰇡
  


󰇢

󰇨
Exception: models B800 / 1000 / 1250 / 1600,
curves 8 and 9* only:
*Curve 9 calculation limited down to 0.1s

󰇧


  



 
󰇨


Refer to Annex B – Time Current Curves for further detail on the pre-defined curves for each B_BE MCCB model.
B250
Pre-defined curve number
Rating (I
n
)
1
2
3
4
5
6
7
8
9
10
40 A
t
r reference
(s)
11
21
21
5
7.5
1
2.5
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
90
120
─
Derived k
28.918
55.206
55.206
139.707
209.561
3.476
6.598
─
125 A
t
r reference
(s)
11
21
21
5
7.5
1
2.5
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
300
375
─
Derived k
28.918
55.206
55.206
139.707
209.561
43.943
172.358
─
160 A
t
r reference
(s)
11
21
21
5
7.5
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
Derived k
28.918
55.206
55.206
139.707
209.561
250 A
t
r reference
(s)
11
21
21
5
7.5
1
2.5
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
600
750
─
Derived k
28.918
55.206
55.206
139.707
209.561
177.277
693.194
─
B400
Pre-defined curve number
Rating (I
n
)
1
2
3
4
5
6
7
8
9
10
250 A
t
r reference
(s)
11
21
21
5
10
19
29
1
2.5
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
6 x I
r
6 x I
r
600
750
─
Derived k
29.918
55.206
55.206
139.707
279.415
530.888
810.302
4.030
16.496
─
400 A
t
r reference
(s)
11
21
21
5
10
19
29
1
2.5
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
6 x I
r
6 x I
r
960
1200
─
Derived k
29.918
55.206
55.206
139.707
279.415
530.888
810.302
4.030
16.496
─
B800
Pre-defined curve number
Rating (I
n
)
1
2
3
4
5
6
7
8
9
10
630 / 800 A
t
r reference
(s)
11
21
21
5
5
10
29
46
1
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
6 x I
r
6 x I
r
1.5 x I
r
3 x I
r
─
Derived k
28.918
55.206
55.206
139.707
139.707
279.415
810.302
177.831
219.205
─
B1000 / 1250 / 1600
Pre-defined curve number
Rating (I
n
)
1
2
3
4
5
6
7
8
9
10
1000 A
t
r reference
(s)
11
21
21
5
5
10
16
46
1
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
6 x I
r
6 x I
r
1.5 x I
r
3 x I
r
─
Derived k
28.918
55.206
55.206
139.707
139.707
279.415
447.063
177.831
219.205
─
B1250 / 1600
Pre-defined curve number
Rating (I
n
)
1
2
3
4
5
6
7
8
9
10
1250 / 1600 A
t
r reference
(s)
11
21
21
5
5
10
29
46
1
─
I
reference
(A)
2 x I
r
2 x I
r
2 x I
r
6 x I
r
6 x I
r
6 x I
r
6 x I
r
1.5 x I
r
3 x I
r
─
Derived k
28.918
55.206
55.206
139.707
139.707
279.415
810.302
177.831
219.205
─
Notice: The trip time tolerance for LTD protection is -20% + 20ms to 0% + 30ms.
Example:
For t
r
= 5 s and I = 6 x I
r
, the trip time for long time delay protection will be between 4.02 s and 5.03 s.