GE 750 Instruction Manual page 132

750/760
Feeder Management Relay
Table 5–10: IAC Curve Trip Times
Multiplier
(TDM)
1.5 2.0
IAC Extremely Inverse
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
IAC Very Inverse
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
IAC Inverse
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
IAC Short Inverse
0.5 0.072 0.047
1.0 0.143 0.095
2.0 0.286 0.190
4.0 0.573 0.379
6.0 0.859 0.569
8.0 1.145 0.759
10.0 1.431 0.948
5–36
IAC Curves:
The curves for the General Electric type IAC relay family are derived from the
formulae:
⎛
T M × A
⎜
= + ----------------------------- -
⎝
( I I ⁄
pu
where: T = trip time (seconds), M = multiplier setpoint, I = input current,
I = pickup current setpoint, A to E = constants.
pickup
Table 5–9: GE Type IAC Inverse Curve Constants
IAC Curve Shape
IAC Extreme Inverse
IAC Very Inverse
IAC Inverse
IAC Short Inverse
Current ( I / I
3.0 4.0 5.0
0.303 0.178 0.123
0.606 0.356 0.246
1.212 0.711 0.491
2.423 1.422 0.983
3.635 2.133 1.474
4.846 2.844 1.966
6.058 3.555 2.457
0.269 0.172 0.133
0.537 0.343 0.266
1.075 0.687 0.533
2.150 1.374 1.065
3.225 2.061 1.598
4.299 2.747 2.131
5.374 3.434 2.663
0.266 0.221 0.196
0.532 0.443 0.392
1.064 0.885 0.784
2.128 1.770 1.569
3.192 2.656 2.353
4.256 3.541 3.138
5.320 4.426 3.922
0.035 0.031 0.028
0.070 0.061 0.057
0.140 0.123 0.114
0.279 0.245 0.228
0.419 0.368 0.341
0.559 0.490 0.455
0.699 0.613 0.569
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B D
+ ------------------------------------- - + ------------------------------------- -
2
( ( I I ⁄ ) C ) ( ( I I
) C
–
–
pu
A B
0.0040 0.6379 0.6200
0.0900 0.7955 0.1000
0.2078 0.8630 0.8000
0.0428 0.0609 0.6200
)
pickup
6.0 7.0
0.093 0.074
0.186 0.149
0.372 0.298
0.744 0.595
1.115 0.893
1.487 1.191
1.859 1.488
0.113 0.101
0.227 0.202
0.453 0.405
0.906 0.810
1.359 1.215
1.813 1.620
2.266 2.025
0.180 0.168
0.360 0.337
0.719 0.674
1.439 1.348
2.158 2.022
2.878 2.695
3.597 3.369
0.027 0.026
0.054 0.052
0.108 0.105
0.217 0.210
0.325 0.314
0.434 0.419
0.542 0.524
S5 Protection
⎞
E
⎟
(EQ 5.4)
3
⎠
⁄ ) C )
–
pu
C D E
1.7872 0.2461
–1.2885 7.9586
–0.4180 0.1947
–0.0010 0.0221
8.0 9.0 10.0
0.062 0.053 0.046
0.124 0.106 0.093
0.248 0.212 0.185
0.495 0.424 0.370
0.743 0.636 0.556
0.991 0.848 0.741
1.239 1.060 0.926
0.093 0.087 0.083
0.186 0.174 0.165
0.372 0.349 0.331
0.745 0.698 0.662
1.117 1.046 0.992
1.490 1.395 1.323
1.862 1.744 1.654
0.160 0.154 0.148
0.320 0.307 0.297
0.640 0.614 0.594
1.280 1.229 1.188
1.921 1.843 1.781
2.561 2.457 2.375
3.201 3.072 2.969
0.026 0.025 0.025
0.051 0.050 0.049
0.102 0.100 0.099
0.204 0.200 0.197
0.307 0.301 0.296
0.409 0.401 0.394
0.511 0.501 0.493
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