GE c60 Instruction Manual page 307

CHAPTER 5: SETTINGS
Table 5-28: 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
IEC curves
For European applications, the relay offers three standard curves defined in IEC 255-4 and British standard BS142. These
are defined as IEC Curve A, IEC Curve B, and IEC Curve C. The formulae for these curves are:
T
where
T = operate time (in seconds)
TDM = Multiplier setting
I = input current
I = Pickup Current setting
pickup
K, E = constants
t = characteristic constant
r
T = reset time in seconds (assuming energy capacity is 100% and
RESET
Table 5-29: IEC (BS) inverse time curve constants
IEC (BS) curve shape
IEC Curve A (BS142)
IEC Curve B (BS142)
IEC Curve C (BS142)
C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUAL
)
3.0 4.0 5.0
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
K
---------------------------------- -
E
,
= TDM  T
 I I   1
–
RESET
pickup
K E t
r
0.140 0.020 9.7
13.500 1.000 43.2
80.000 2.000 58.2
6.0 7.0 8.0
0.464 0.355 0.285
0.927 0.709 0.569
1.855 1.418 1.139
3.710 2.837 2.277
5.564 4.255 3.416
7.419 5.674 4.555
9.274 7.092 5.693
0.526 0.450 0.401
1.051 0.900 0.802
2.103 1.799 1.605
4.205 3.598 3.209
6.308 5.397 4.814
8.410 7.196 6.418
10.513 8.995 8.023
0.763 0.706 0.663
1.526 1.412 1.327
3.051 2.823 2.653
6.102 5.647 5.307
9.153 8.470 7.960
12.204 11.294 10.614
15.255 14.117 13.267
t
r
---------------------------------- -
= TDM 
2
1  I I  
–
pickup
is "Timed")
RESET
GROUPED ELEMENTS
9.0 10.0
0.237 0.203
0.474 0.407
0.948 0.813
1.897 1.626
2.845 2.439
3.794 3.252
4.742 4.065
0.368 0.345
0.736 0.689
1.472 1.378
2.945 2.756
4.417 4.134
5.889 5.513
7.361 6.891
0.630 0.603
1.260 1.207
2.521 2.414
5.041 4.827
7.562 7.241
10.083 9.654
12.604 12.068
Eq. 5-9
5-181
5