GE D90 Plus Instruction Manual page 241

CHAPTER 7: PROTECTION
Table 7-1: IEEE curve trip times (in seconds)
Multiplier Current (I / I
pickup
(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
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Table 13: IEEE inverse time curve constants
IEEE curve shape
IEEE Extremely Inverse
IEEE Very Inverse
IEEE Moderately Inverse
)
3.0 4.0
1.823 1.001
3.647 2.002
7.293 4.003
14.587 8.007
21.880 12.010
29.174 16.014
36.467 20.017
1.471 0.899
2.942 1.798
5.885 3.597
11.769 7.193
17.654 10.790
23.538 14.387
29.423 17.983
1.216 0.973
2.432 1.946
4.864 3.892
9.729 7.783
14.593 11.675
19.458 15.567
24.322 19.458
IEC curves
For European applications, the D90
and British standard BS142. These are defined as IEC Curve A, IEC Curve B, and IEC Curve C.
The IEC curves are derived by the operate and reset time equations.
where
• T = operate time (in seconds)
operate
• TDM = multiplier setting
• I = input current
A B
28.2 0.1217
19.61 0.491
0.0515 0.1140
5.0 6.0 7.0
0.648 0.464 0.355
1.297 0.927 0.709
2.593 1.855 1.418
5.187 3.710 2.837
7.780 5.564 4.255
10.374 7.419 5.674
12.967 9.274 7.092
0.654 0.526 0.450
1.308 1.051 0.900
2.616 2.103 1.799
5.232 4.205 3.598
7.849 6.308 5.397
10.465 8.410 7.196
13.081 10.513 8.995
0.844 0.763 0.706
1.688 1.526 1.412
3.377 3.051 2.823
6.753 6.102 5.647
10.130 9.153 8.470
13.507 12.204 11.294
16.883 15.255 14.117
Plus
offers three standard curves defined in IEC 255-4
GROUPED PROTECTION ELEMENTS
p t
r
2.0000 29.1
2.0000 21.6
0.02000 4.85
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
Eq. 12
Eq. 13
231