# GE UR Series Instruction Manual Page 166

Line differential relay.

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

L90