GE 845 Instruction Manual page 284

PROTECTION
MULTIPLIER CURRENT (I/Ipickup)
(TDM)
1.5
2.0 8.002
4.0 16.004
6.0 24.005
8.0 32.007
10.0 40.009
ANSI VERY INVERSE
0.5 1.567
1.0 3.134
2.0 6.268
4.0 12.537
6.0 18.805
8.0 25.073
10.0 31.341
ANSI NORMALLY INVERSE
0.5 2.142
1.0 4.284
2.0 8.568
4.0 17.137
6.0 25.705
8.0 34.274
10.0 42.842
ANSI MODERATELY INVERSE
0.5 0.675
1.0 1.351
2.0 2.702
4.0 5.404
6.0 8.106
8.0 10.807
10.0 13.509
4–156
2.0 3.0 4.0
3.489 1.319 0.736
6.977 2.638 1.472
10.466 3.956 2.208
13.955 5.275 2.944
17.443 6.594 3.680
0.663 0.268 0.171
1.325 0.537 0.341
2.650 1.074 0.682
5.301 2.148 1.365
7.951 3.221 2.047
10.602 4.295 2.730
13.252 5.369 3.412
0.883 0.377 0.256
1.766 0.754 0.513
3.531 1.508 1.025
7.062 3.016 2.051
10.594 4.524 3.076
14.125 6.031 4.102
17.656 7.539 5.127
0.379 0.239 0.191
0.757 0.478 0.382
1.515 0.955 0.764
3.030 1.910 1.527
4.544 2.866 2.291
6.059 3.821 3.054
7.574 4.776 3.818
IEC CURVES
For European applications, the relay offers three standard curves defined in IEC 255-4 and
British standard BS142. These are defined as IEC Curve A, IEC Curve B, and IEC Curve C. The
formula for these curves is:
Where:
T = operate time (in seconds)
TDM = Multiplier setting
I = input current
I = Pickup Current setting
pickup
K, E = constants
t = characteristic constant
r
T = reset time in seconds (assuming energy capacity is 100% and RESET is
RESET
"Timed")
5.0 6.0 7.0
0.495 0.371 0.298
0.990 0.742 0.596
1.484 1.113 0.894
1.979 1.483 1.192
2.474 1.854 1.491
0.130 0.108 0.094
0.260 0.216 0.189
0.520 0.432 0.378
1.040 0.864 0.755
1.559 1.297 1.133
2.079 1.729 1.510
2.599 2.161 1.888
0.203 0.172 0.151
0.407 0.344 0.302
0.814 0.689 0.604
1.627 1.378 1.208
2.441 2.067 1.812
3.254 2.756 2.415
4.068 3.445 3.019
0.166 0.151 0.141
0.332 0.302 0.281
0.665 0.604 0.563
1.329 1.208 1.126
1.994 1.812 1.689
2.659 2.416 2.252
3.324 3.020 2.815
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
8.0 9.0 10.0
0.251 0.219 0.196
0.503 0.439 0.393
0.754 0.658 0.589
1.006 0.878 0.786
1.257 1.097 0.982
0.085 0.078 0.073
0.170 0.156 0.146
0.340 0.312 0.291
0.680 0.625 0.583
1.020 0.937 0.874
1.360 1.250 1.165
1.700 1.562 1.457
0.135 0.123 0.113
0.270 0.246 0.226
0.541 0.492 0.452
1.082 0.983 0.904
1.622 1.475 1.356
2.163 1.967 1.808
2.704 2.458 2.260
0.133 0.128 0.123
0.267 0.255 0.247
0.533 0.511 0.493
1.066 1.021 0.986
1.600 1.532 1.479
2.133 2.043 1.972
2.666 2.554 2.465