GE C70 Instruction Manual page 284

GROUPED ELEMENTS
Multiplier Current ( I / I
(TDM)
1.5
0.20 12.800
0.40 25.600
0.60 38.400
0.80 51.200
1.00 64.000
IEC Short Inverse
0.05 0.153
0.10 0.306
0.20 0.612
0.40 1.223
0.60 1.835
0.80 2.446
1.00 3.058
IAC curves
The curves for the General Electric type IAC relay family are derived from the formulae:
TDM
T =
5
where
T = operate time (in seconds)
TDM = Multiplier setting
I = Input current
I = Pickup Current setting
pkp
A to E = constants defined in the table
t = characteristic constant defined in the table
r
T = reset time in seconds (assuming energy capacity is 100% and RESET 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: GE type IAC curve trip times
Multiplier Current ( I / I
(TDM)
1.5
IAC Extremely Inverse
0.5 1.699
1.0 3.398
2.0 6.796
4.0 13.591
6.0 20.387
8.0 27.183
10.0 33.979
5-160
)
pickup
2.0 3.0 4.0
5.333 2.000 1.067
10.667 4.000 2.133
16.000 6.000 3.200
21.333 8.000 4.267
26.667 10.000 5.333
0.089 0.056 0.044
0.178 0.111 0.088
0.356 0.223 0.175
0.711 0.445 0.351
1.067 0.668 0.526
1.423 0.890 0.702
1.778 1.113 0.877
B D

A + -------------------------- - + ---------------------------------
× 
( I I ⁄ ) C
( ( ⁄ ) C
I I

–
–
pkp
pkp
A B
0.0040 0.6379
0.0900 0.7955
0.2078 0.8630
0.0428 0.0609
)
pickup
2.0 3.0 4.0
0.749 0.303 0.178
1.498 0.606 0.356
2.997 1.212 0.711
5.993 2.423 1.422
8.990 3.635 2.133
11.987 4.846 2.844
14.983 6.058 3.555
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
5.0 6.0 7.0
0.667 0.457 0.333
1.333 0.914 0.667
2.000 1.371 1.000
2.667 1.829 1.333
3.333 2.286 1.667
0.038 0.034 0.031
0.075 0.067 0.062
0.150 0.135 0.124
0.301 0.269 0.247
0.451 0.404 0.371
0.602 0.538 0.494
0.752 0.673 0.618
E

+ ---------------------------------
 ,
T
2 3
) ( ( ⁄ ) C ) RESET
I I

–
pkp
C D
0.6200 1.7872
0.1000 –1.2885
0.8000 –0.4180
0.6200 –0.0010
5.0 6.0 7.0
0.123 0.093 0.074
0.246 0.186 0.149
0.491 0.372 0.298
0.983 0.744 0.595
1.474 1.115 0.893
1.966 1.487 1.191
2.457 1.859 1.488
CHAPTER 5: SETTINGS
8.0 9.0
0.254 0.200
0.508 0.400
0.762 0.600
1.016 0.800
1.270 1.000
0.029 0.027
0.058 0.054
0.115 0.109
0.231 0.218
0.346 0.327
0.461 0.435
0.576 0.544
t
= r
TDM × ---------------------------- -
2
1 ( I I ⁄ )
–
pkp
E t
r
0.2461 6.008
7.9586 4.678
0.1947 0.990
0.0221 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
10.0
0.162
0.323
0.485
0.646
0.808
0.026
0.052
0.104
0.207
0.311
0.415
0.518
Eq. 5-9