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5 SETTINGS
IAC CURVES:
The curves for the General Electric type IAC relay family are derived from the formulae:
⎛
×
A
+
----------------------------- -
⎜
TDM
T
=
(
⎝
I I
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 5–17: GE TYPE IAC INVERSE TIME CURVE CONSTANTS
IAC CURVE SHAPE
IAC Extreme Inverse
IAC Very Inverse
IAC Inverse
IAC Short Inverse
Table 5–18: 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
+
------------------------------------- -
+
------------------------------------- -
⁄
) C
2
(
(
⁄
) C
)
(
–
I I
–
pkp
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
C70 Capacitor Bank Protection and Control System
⎞
E
⎟
T
,
=
TDM
3
(
⁄
) C
)
RESET
⎠
I I
–
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
0.186
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
5.6 GROUPED ELEMENTS
t
r
×
(EQ 5.9)
------------------------------- -
2
(
⁄
)
1
I I
–
pkp
E
T
R
6.008
4.678
0.990
0.222
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
5-119
5
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