GE T60 Instruction Manual page 349

5 SETTINGS
IAC CURVES:
The curves for the General Electric type IAC relay family are derived from the formulae:

----------------------------- -
A
+
TDM × 
T
=
( I I ⁄

pkp
where: T = operate time (in seconds), TDM = Multiplier setting, I = Input current, I
constants, t = characteristic constant, and T
r
and is "Timed")
RESET
Table 5–26: GE TYPE IAC INVERSE TIME CURVE CONSTANTS
IAC CURVE SHAPE
IAC Extreme Inverse
IAC Very Inverse
IAC Inverse
IAC Short Inverse
Table 5–27: 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
GE Multilin
B D
------------------------------------- - ------------------------------------- -
+ +
2
) C
( ( ⁄ ) C ) ( ( ⁄
I I I I
–
–
pkp
RESET
A B
0.0040 0.6379
0.0900 0.7955
0.2078 0.8630
0.0428 0.0609
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
T60 Transformer Protection System
E


T
,
= TDM
3
RESET
) C )

–
pkp
= Pickup Current setting, A to E =
pkp
= reset time in seconds (assuming energy capacity is 100%
C D
0.6200 1.7872 0.2461
0.1000 –1.2885 7.9586
0.8000 –0.4180 0.1947
0.6200 –0.0010 0.0221
)
pickup
6.0 7.0
0.093 0.074 0.062
0.186 0.149 0.124
0.372 0.298 0.248
0.744 0.595 0.495
1.115 0.893 0.743
1.487 1.191 0.991
1.859 1.488 1.239
0.113 0.101 0.093
0.227 0.202 0.186
0.453 0.405 0.372
0.906 0.810 0.745
1.359 1.215 1.117
1.813 1.620 1.490
2.266 2.025 1.862
0.180 0.168 0.160
0.360 0.337 0.320
0.719 0.674 0.640
1.439 1.348 1.280
2.158 2.022 1.921
2.878 2.695 2.561
3.597 3.369 3.201
0.027 0.026 0.026
0.054 0.052 0.051
0.108 0.105 0.102
0.217 0.210 0.204
0.325 0.314 0.307
0.434 0.419 0.409
0.542 0.524 0.511
5.6 GROUPED ELEMENTS
t
r
(EQ 5.31)
× ------------------------------- -
2
1 ( I I ⁄ )
–
pkp
E T
R
6.008
4.678
0.990
0.222
8.0 9.0 10.0
0.053 0.046
0.106 0.093
0.212 0.185
0.424 0.370
0.636 0.556
0.848 0.741
1.060 0.926
0.087 0.083
0.174 0.165
0.349 0.331
0.698 0.662
1.046 0.992
1.395 1.323
1.744 1.654
0.154 0.148
0.307 0.297
0.614 0.594
1.229 1.188
1.843 1.781
2.457 2.375
3.072 2.969
0.025 0.025
0.050 0.049
0.100 0.099
0.200 0.197
0.301 0.296
0.401 0.394
0.501 0.493
5-213
5