GE 889 - Page 290

4–160 889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
PROTECTION CHAPTER 4: SETPOINTS
Table 4-27: IEC CURVE TRIP TIMES (IN SECONDS)
IAC CURVES
The curves for the General Electric type IAC relay family are derived from the formula:
Where:
T = operate time (in seconds)
TDM = Multiplier setting
I = input current
I
pickup
= Pickup Current setting
MULTIPLIER
(TDM)
CURRENT (I/I
pickup
)
1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
IEC CURVE A
0.05 0.860 0.501 0.315 0.249 0.214 0.192 0.176 0.165 0.156 0.149
0.10 1.719 1.003 0.630 0.498 0.428 0.384 0.353 0.330 0.312 0.297
0.20 3.439 2.006 1.260 0.996 0.856 0.767 0.706 0.659 0.623 0.594
0.40 6.878 4.012 2.521 1.992 1.712 1.535 1.411 1.319 1.247 1.188
0.60 10.317 6.017 3.781 2.988 2.568 2.302 2.117 1.978 1.870 1.782
0.80 13.755 8.023 5.042 3.984 3.424 3.070 2.822 2.637 2.493 2.376
1.00 17.194 10.029 6.302 4.980 4.280 3.837 3.528 3.297 3.116 2.971
IEC CURVE B
0.05 1.350 0.675 0.338 0.225 0.169 0.135 0.113 0.096 0.084 0.075
0.10 2.700 1.350 0.675 0.450 0.338 0.270 0.225 0.193 0.169 0.150
0.20 5.400 2.700 1.350 0.900 0.675 0.540 0.450 0.386 0.338 0.300
0.40 10.800 5.400 2.700 1.800 1.350 1.080 0.900 0.771 0.675 0.600
0.60 16.200 8.100 4.050 2.700 2.025 1.620 1.350 1.157 1.013 0.900
0.80 21.600 10.800 5.400 3.600 2.700 2.160 1.800 1.543 1.350 1.200
1.00 27.000 13.500 6.750 4.500 3.375 2.700 2.250 1.929 1.688 1.500
IEC CURVE C
0.05 3.200 1.333 0.500 0.267 0.167 0.114 0.083 0.063 0.050 0.040
0.10 6.400 2.667 1.000 0.533 0.333 0.229 0.167 0.127 0.100 0.081
0.20 12.800 5.333 2.000 1.067 0.667 0.457 0.333 0.254 0.200 0.162
0.40 25.600 10.667 4.000 2.133 1.333 0.914 0.667 0.508 0.400 0.323
0.60 38.400 16.000 6.000 3.200 2.000 1.371 1.000 0.762 0.600 0.485
0.80 51.200 21.333 8.000 4.267 2.667 1.829 1.333 1.016 0.800 0.646
1.00 64.000 26.667 10.000 5.333 3.333 2.286 1.667 1.270 1.000 0.808
IEC SHORT INVERSE
0.05 0.153 0.089 0.056 0.044 0.038 0.034 0.031 0.029 0.027 0.026
0.10 0.306 0.178 0.111 0.088 0.075 0.067 0.062 0.058 0.054 0.052
0.20 0.612 0.356 0.223 0.175 0.150 0.135 0.124 0.115 0.109 0.104
0.40 1.223 0.711 0.445 0.351 0.301 0.269 0.247 0.231 0.218 0.207
0.60 1.835 1.067 0.668 0.526 0.451 0.404 0.371 0.346 0.327 0.311
0.80 2.446 1.423 0.890 0.702 0.602 0.538 0.494 0.461 0.435 0.415
1.00 3.058 1.778 1.113 0.877 0.752 0.673 0.618 0.576 0.544 0.518