GE 745 Instruction Manual page 158

S4 ELEMENTS
5–62
Table 5–7: IEC curve trip times (in seconds)
TDM
1.5 2.0
0.20 0.612 0.356
0.40 1.223 0.711
0.60 1.835 1.067
0.80 2.446 1.423
1.00 3.058 1.778
IAC curves:
The curves for the General Electric type IAC relay family are derived from the formulae:

T M ×  A
= +

where: T = trip time (in seconds), M = multiplier setpoint, I = input current,
I = pickup current setpoint, and A to E are constants.
pickup
Table 5–8: GE type IAC inverse curve constants
IAC curve shape
IAC extreme inverse
IAC very inverse
IAC inverse
IAC short inverse
TDM
1.5 2.0
0.5 1.699 0.749
1.0 3.398 1.498
2.0 6.796 2.997
4.0 13.591 5.993
6.0 20.387 8.990
8.0 27.183 11.987
10.0 33.979 14.983
0.5 1.451 0.656
1.0 2.901 1.312
2.0 5.802 2.624
4.0 11.605 5.248
6.0 17.407 7.872
8.0 23.209 10.497
10.0 29.012 13.121
0.5 0.578 0.375
1.0 1.155 0.749
2.0 2.310 1.499
4.0 4.621 2.997
6.0 6.931 4.496
8.0 9.242 5.995
10.0 11.552 7.494
Current ( I / I
pickup
3.0 4.0 5.0 6.0
0.223 0.175 0.150 0.135
0.445 0.351 0.301 0.269
0.668 0.526 0.451 0.404
0.890 0.702 0.602 0.538
1.113 0.877 0.752 0.673
B D
------------------------- - --------------------------------- -
+ +
2
( ( I I ⁄ ) C )
( I I ⁄ ) C
–
–
pu
pu
A B
0.0040 0.6379
0.0900 0.7955
0.2078 0.8630
0.0428 0.0609
Table 5–9: IAC curve trip times
Current ( I / I
pickup
3.0 4.0 5.0 6.0
IAC extremely inverse
0.303 0.178 0.123 0.093
0.606 0.356 0.246 0.186
1.212 0.711 0.491 0.372
2.423 1.422 0.983 0.744
3.635 2.133 1.474 1.115
4.846 2.844 1.966 1.487
6.058 3.555 2.457 1.859
IAC very inverse
0.269 0.172 0.133 0.113
0.537 0.343 0.266 0.227
1.075 0.687 0.533 0.453
2.150 1.374 1.065 0.906
3.225 2.061 1.598 1.359
4.299 2.747 2.131 1.813
5.374 3.434 2.663 2.266
IAC inverse
0.266 0.221 0.196 0.180
0.532 0.443 0.392 0.360
1.064 0.885 0.784 0.719
2.128 1.770 1.569 1.439
3.192 2.656 2.353 2.158
4.256 3.541 3.138 2.878
5.320 4.426 3.922 3.597
745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
)
7.0 8.0 9.0
0.124 0.115 0.109
0.247 0.231 0.218
0.371 0.346 0.327
0.494 0.461 0.435
0.618 0.576 0.544

E
--------------------------------- - 
3

( ( I I ⁄ ) C )
–
pu
C D
0.6200 1.7872
0.1000 –1.2885
0.8000 –0.4180
0.6200 –0.0010
)
7.0 8.0 9.0
0.074 0.062 0.053
0.149 0.124 0.106
0.298 0.248 0.212
0.595 0.495 0.424
0.893 0.743 0.636
1.191 0.991 0.848
1.488 1.239 1.060
0.101 0.093 0.087
0.202 0.186 0.174
0.405 0.372 0.349
0.810 0.745 0.698
1.215 1.117 1.046
1.620 1.490 1.395
2.025 1.862 1.744
0.168 0.160 0.154
0.337 0.320 0.307
0.674 0.640 0.614
1.348 1.280 1.229
2.022 1.921 1.843
2.695 2.561 2.457
3.369 3.201 3.072
10.0
0.104
0.207
0.311
0.415
0.518
(EQ 5.9)
E
0.2461
7.9586
0.1947
0.0221
10.0
0.046
0.093
0.185
0.370
0.556
0.741
0.926
0.083
0.165
0.331
0.662
0.992
1.323
1.654
0.148
0.297
0.594
1.188
1.781
2.375
2.969