5 SETTINGS
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
=
where: T = operate time (in seconds), TDM = Multiplier setting, I = input current, I
A, B, p = constants, T
t
= characteristic constant
r
Table 5–13: IEEE INVERSE TIME CURVE CONSTANTS
IEEE CURVE SHAPE
IEEE Extremely Inverse
IEEE Very Inverse
IEEE Moderately Inverse
Table 5–14: IEEE CURVE TRIP TIMES (IN SECONDS)
MULTIPLIER
(TDM)
1.5
2.0
IEEE EXTREMELY INVERSE
0.5
11.341
4.761
1.0
22.682
9.522
2.0
45.363
19.043
4.0
90.727
38.087
6.0
136.090
57.130
8.0
181.454
76.174
10.0
226.817
95.217
IEEE VERY INVERSE
0.5
8.090
3.514
1.0
16.179
7.028
2.0
32.358
14.055
4.0
64.716
28.111
6.0
97.074
42.166
8.0
129.432
56.221
10.0
161.790
70.277
IEEE MODERATELY INVERSE
0.5
3.220
1.902
1.0
6.439
3.803
2.0
12.878
7.606
4.0
25.756
15.213
6.0
38.634
22.819
8.0
51.512
30.426
10.0
64.390
38.032
GE Multilin
A
--------------------------------- -
B
+
p
I
×
T
,
--------------- -
1
–
RESET
I
pickup
= reset time in seconds (assuming energy capacity is 100% and
RESET
A
B
28.2
0.1217
19.61
0.491
0.0515
0.1140
CURRENT ( I / I
3.0
4.0
1.823
1.001
0.648
3.647
2.002
1.297
7.293
4.003
2.593
14.587
8.007
5.187
21.880
12.010
7.780
29.174
16.014
10.374
36.467
20.017
12.967
1.471
0.899
0.654
2.942
1.798
1.308
5.885
3.597
2.616
11.769
7.193
5.232
17.654
10.790
7.849
23.538
14.387
10.465
29.423
17.983
13.081
1.216
0.973
0.844
2.432
1.946
1.688
4.864
3.892
3.377
9.729
7.783
6.753
14.593
11.675
10.130
19.458
15.567
13.507
24.322
19.458
16.883
B30 Bus Differential System
t
r
----------------------------------- -
TDM
×
I
2
=
--------------- -
1
–
I
pickup
= Pickup Current setting
pickup
P
T
R
2.0000
29.1
2.0000
21.6
0.02000
4.85
)
pickup
5.0
6.0
7.0
0.464
0.355
0.927
0.709
1.855
1.418
3.710
2.837
5.564
4.255
7.419
5.674
9.274
7.092
0.526
0.450
1.051
0.900
2.103
1.799
4.205
3.598
6.308
5.397
8.410
7.196
10.513
8.995
0.763
0.706
1.526
1.412
3.051
2.823
6.102
5.647
9.153
8.470
12.204
11.294
15.255
14.117
5.6 GROUPED ELEMENTS
(EQ 5.4)
is "Timed"),
RESET
8.0
9.0
10.0
0.285
0.237
0.203
0.569
0.474
0.407
1.139
0.948
0.813
2.277
1.897
1.626
3.416
2.845
2.439
4.555
3.794
3.252
5.693
4.742
4.065
0.401
0.368
0.345
0.802
0.736
0.689
1.605
1.472
1.378
3.209
2.945
2.756
4.814
4.417
4.134
6.418
5.889
5.513
8.023
7.361
6.891
0.663
0.630
0.603
1.327
1.260
1.207
2.653
2.521
2.414
5.307
5.041
4.827
7.960
7.562
7.241
10.614
10.083
9.654
13.267
12.604
12.068
5-111
5