GE UR Series Instruction Manual page 166

5.5 GROUPED ELEMENTS
IEEE CURVES:
The IEEE time overcurrent curve shapes conform to industry standards and the IEEE C37.112-1996 curve classifications
for extremely, very, and moderately inverse. The IEEE curves are derived from the formulae:
--------------------------------- -
× 
T TDM
=
--------------- -

I
pickup
where: T = Operate Time (sec.)
TDM = Multiplier Setting
I = Input Current
I = Pickup Current Setting
pickup
A , B , p = Constants
T = reset time in sec. (assuming energy capacity is 100% and RESET: Timed)
RESET
t = characteristic constant
r
Table 5–16: IEEE INVERSE TIME CURVE CONSTANTS
IEEE CURVE SHAPE
IEEE EXTREMELY INVERSE
IEEE VERY INVERSE
IEEE MODERATELY INVERSE
Table 5–17: IEEE CURVE TRIP TIMES (IN SECONDS)
5
MULTIPLIER
(TDM)
1.5
IEEE EXTREMELY INVERSE
0.5 11.341
1.0 22.682
2.0 45.363
4.0 90.727
6.0 136.090
8.0 181.454
10.0 226.817
IEEE VERY INVERSE
0.5 8.090
1.0 16.179
2.0 32.358
4.0 64.716
6.0 97.074
8.0 129.432
10.0 161.790
IEEE MODERATELY INVERSE
0.5 3.220
1.0 6.439
2.0 12.878
4.0 25.756
6.0 38.634
8.0 51.512
10.0 64.390
5-82
A
B
+
 p
I
T
1
–
RESET

A
28.2
19.61
0.0515
2.0 3.0 4.0
4.761 1.823 1.001
9.522 3.647 2.002
19.043 7.293 4.003
38.087 14.587 8.007
57.130 21.880 12.010
76.174 29.174 16.014
95.217 36.467 20.017
3.514 1.471 0.899
7.028 2.942 1.798
14.055 5.885 3.597
28.111 11.769 7.193
42.166 17.654 10.790
56.221 23.538 14.387
70.277 29.423 17.983
1.902 1.216 0.973
3.803 2.432 1.946
7.606 4.864 3.892
15.213 9.729 7.783
22.819 14.593 11.675
30.426 19.458 15.567
38.032 24.322 19.458
L90 Line Differential Relay
t
r
--------------------------------- -
×
TDM   2
=
I
--------------- - – 1
 
I
pickup
B P
0.1217 2.0000
0.491 2.0000
0.1140 0.02000
CURRENT ( I / I )
pickup
5.0 6.0
0.648 0.464
1.297 0.927
2.593 1.855
5.187 3.710
7.780 5.564
10.374 7.419
12.967 9.274
0.654 0.526
1.308 1.051
2.616 2.103
5.232 4.205
7.849 6.308
10.465 8.410
13.081 10.513
0.844 0.763
1.688 1.526
3.377 3.051
6.753 6.102
10.130 9.153
13.507 12.204 11.294
16.883 15.255 14.117
5 SETTINGS
T
R
29.1
21.6
4.85
7.0 8.0 9.0
0.355 0.285 0.237
0.709 0.569 0.474
1.418 1.139 0.948
2.837 2.277 1.897
4.255 3.416 2.845
5.674 4.555 3.794
7.092 5.693 4.742
0.450 0.401 0.368
0.900 0.802 0.736
1.799 1.605 1.472
3.598 3.209 2.945
5.397 4.814 4.417
7.196 6.418 5.889
8.995 8.023 7.361
0.706 0.663 0.630
1.412 1.327 1.260
2.823 2.653 2.521
5.647 5.307 5.041
8.470 7.960 7.562
10.614 10.083
13.267 12.604
GE Power Management
10.0
0.203
0.407
0.813
1.626
2.439
3.252
4.065
0.345
0.689
1.378
2.756
4.134
5.513
6.891
0.603
1.207
2.414
4.827
7.241
9.654
12.068