Appendix E IEEE Inverse Time Protection Tables
The times shown for the inverse time curves in this appendix are calculated according to the formulas defined in the IEEE Standard.
-
Standard Moderately Inverse = (0.0515 / (I^0.02 - 1)) + 0.114
-
Standard Very Inverse = (19.61 / (I^2-1)) + 0.491
-
Standard Extremely Inverse = (28.2 / (I^2-1)) + 0.1217
Where I is the fault current expressed as a multiple of the setting current.
Each curve is defined in terms of a formula such as:
Time = T / (IN – Q) + B
Where:
T = time parameter specific to characteristic
I = ratio of fault current to setting current
N = parameter specific to characteristic
Q = parameter specific to characteristic
B = parameter specific to characteristic
Tables for the times to trip for each of these curves are shown in the table below.
Table 105 IEEE Inverse Curves Timing Table
|
Setting Current Multiple |
Standard Moderately Inverse Time (s) |
Standard Very Inverse Time (s) |
Standard Extremely Inverse Time (s) |
|---|---|---|---|
|
1.10 |
27.11 |
93.87 |
134.41 |
|
1.50 |
6.44 |
16.18 |
22.68 |
|
2.00 |
3.80 |
7.03 |
9.52 |
|
2.50 |
2.90 |
4.23 |
5.49 |
|
3.00 |
2.43 |
2.94 |
3.65 |
|
3.50 |
2.14 |
2.23 |
2.63 |
|
4.00 |
1.95 |
1.80 |
2.00 |
|
4.50 |
1.80 |
1.51 |
1.59 |
|
5.00 |
1.69 |
1.31 |
1.30 |
|
5.50 |
1.60 |
1.16 |
1.09 |
|
6.00 |
1.53 |
1.05 |
0.93 |
|
6.50 |
1.46 |
0.97 |
0.81 |
|
7.00 |
1.41 |
0.90 |
0.71 |
|
7.50 |
1.37 |
0.85 |
0.63 |
|
8.00 |
1.33 |
0.80 |
0.57 |
|
8.50 |
1.29 |
0.77 |
0.52 |
|
9.00 |
1.26 |
0.74 |
0.47 |
|
9.50 |
1.23 |
0.71 |
0.44 |
|
10.00 |
1.21 |
0.69 |
0.41 |
|
10.50 |
1.18 |
0.67 |
0.38 |
|
11.00 |
1.16 |
0.65 |
0.36 |
|
11.50 |
1.14 |
0.64 |
0.34 |
|
12.00 |
1.12 |
0.63 |
0.32 |
|
12.50 |
1.11 |
0.62 |
0.30 |
|
13.00 |
1.09 |
0.61 |
0.29 |
|
13.50 |
1.08 |
0.60 |
0.28 |
|
14.00 |
1.06 |
0.59 |
0.27 |
|
14.50 |
1.05 |
0.58 |
0.26 |
|
15.00 |
1.04 |
0.58 |
0.25 |
|
15.50 |
1.03 |
0.57 |
0.24 |
|
16.00 |
1.02 |
0.57 |
0.23 |
|
16.50 |
1.01 |
0.56 |
0.23 |
|
17.00 |
1.00 |
0.56 |
0.22 |
|
17.50 |
0.99 |
0.56 |
0.21 |
|
18.00 |
0.98 |
0.55 |
0.21 |
|
18.50 |
0.97 |
0.55 |
0.20 |
|
19.00 |
0.96 |
0.55 |
0.20 |
|
19.50 |
0.96 |
0.54 |
0.20 |
|
20.00 |
0.95 |
0.54 |
0.19 |
|
20.50 |
0.94 |
0.54 |
0.19 |
|
21.00 |
0.93 |
0.54 |
0.19 |
|
21.50 |
0.93 |
0.53 |
0.18 |
|
22.00 |
0.92 |
0.53 |
0.18 |
|
22.50 |
0.92 |
0.53 |
0.18 |
|
23.00 |
0.91 |
0.53 |
0.18 |
|
23.50 |
0.90 |
0.53 |
0.17 |
|
24.00 |
0.90 |
0.53 |
0.17 |
|
24.50 |
0.89 |
0.52 |
0.17 |
|
25.00 |
0.89 |
0.52 |
0.17 |
|
25.50 |
0.88 |
0.52 |
0.17 |
|
26.00 |
0.88 |
0.52 |
0.16 |
|
26.50 |
0.87 |
0.52 |
0.16 |
|
27.00 |
0.87 |
0.52 |
0.16 |
|
27.50 |
0.87 |
0.52 |
0.16 |
|
28.00 |
0.86 |
0.52 |
0.16 |
|
28.50 |
0.86 |
0.52 |
0.16 |
|
29.00 |
0.85 |
0.51 |
0.16 |
|
29.50 |
0.85 |
0.51 |
0.15 |
|
30.00 |
0.85 |
0.51 |
0.15 |