GE Multilin F35 Multiple Feeder Protection System 5-1375 SETTINGS 5.6 GROUPED ELEMENTS5IAC CURVES:The curves for the General Electric type IAC relay family are derived from the formulae:, (EQ 5.10)where: T = operate time (in seconds), TDM = Multiplier setting, I = Input current, Ipkp = Pickup Current setting, A to E =constants, t r = characteristic constant, and T RESET = reset time in seconds (assuming energy capacity is 100%and RESET is “Timed”)Table 5–21: GE TYPE IAC INVERSE TIME CURVE CONSTANTSIAC CURVE SHAPE A B C D E TRIAC Extreme Inverse 0.0040 0.6379 0.6200 1.7872 0.2461 6.008IAC Very Inverse 0.0900 0.7955 0.1000 –1.2885 7.9586 4.678IAC Inverse 0.2078 0.8630 0.8000 –0.4180 0.1947 0.990IAC Short Inverse 0.0428 0.0609 0.6200 –0.0010 0.0221 0.222Table 5–22: IAC CURVE TRIP TIMESMULTIPLIER(TDM) CURRENT ( I / I pickup)1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0IAC EXTREMELY INVERSE0.5 1.699 0.749 0.303 0.178 0.123 0.093 0.074 0.062 0.053 0.0461.0 3.398 1.498 0.606 0.356 0.246 0.186 0.149 0.124 0.106 0.0932.0 6.796 2.997 1.212 0.711 0.491 0.372 0.298 0.248 0.212 0.1854.0 13.591 5.993 2.423 1.422 0.983 0.744 0.595 0.495 0.424 0.3706.0 20.387 8.990 3.635 2.133 1.474 1.115 0.893 0.743 0.636 0.5568.0 27.183 11.987 4.846 2.844 1.966 1.487 1.191 0.991 0.848 0.74110.0 33.979 14.983 6.058 3.555 2.457 1.859 1.488 1.239 1.060 0.926IAC VERY INVERSE0.5 1.451 0.656 0.269 0.172 0.133 0.113 0.101 0.093 0.087 0.0831.0 2.901 1.312 0.537 0.343 0.266 0.227 0.202 0.186 0.174 0.1652.0 5.802 2.624 1.075 0.687 0.533 0.453 0.405 0.372 0.349 0.3314.0 11.605 5.248 2.150 1.374 1.065 0.906 0.810 0.745 0.698 0.6626.0 17.407 7.872 3.225 2.061 1.598 1.359 1.215 1.117 1.046 0.9928.0 23.209 10.497 4.299 2.747 2.131 1.813 1.620 1.490 1.395 1.32310.0 29.012 13.121 5.374 3.434 2.663 2.266 2.025 1.862 1.744 1.654IAC INVERSE0.5 0.578 0.375 0.266 0.221 0.196 0.180 0.168 0.160 0.154 0.1481.0 1.155 0.749 0.532 0.443 0.392 0.360 0.337 0.320 0.307 0.2972.0 2.310 1.499 1.064 0.885 0.784 0.719 0.674 0.640 0.614 0.5944.0 4.621 2.997 2.128 1.770 1.569 1.439 1.348 1.280 1.229 1.1886.0 6.931 4.496 3.192 2.656 2.353 2.158 2.022 1.921 1.843 1.7818.0 9.242 5.995 4.256 3.541 3.138 2.878 2.695 2.561 2.457 2.37510.0 11.552 7.494 5.320 4.426 3.922 3.597 3.369 3.201 3.072 2.969IAC SHORT INVERSE0.5 0.072 0.047 0.035 0.031 0.028 0.027 0.026 0.026 0.025 0.0251.0 0.143 0.095 0.070 0.061 0.057 0.054 0.052 0.051 0.050 0.0492.0 0.286 0.190 0.140 0.123 0.114 0.108 0.105 0.102 0.100 0.0994.0 0.573 0.379 0.279 0.245 0.228 0.217 0.210 0.204 0.200 0.1976.0 0.859 0.569 0.419 0.368 0.341 0.325 0.314 0.307 0.301 0.2968.0 1.145 0.759 0.559 0.490 0.455 0.434 0.419 0.409 0.401 0.39410.0 1.431 0.948 0.699 0.613 0.569 0.542 0.524 0.511 0.501 0.493T TDM A BI I pkp⁄( ) C–------------------------------ DI I pkp⁄( ) C–( )2-------------------------------------- EI I pkp⁄( ) C–( )3--------------------------------------+ + + ×= T RESET TDM t r1 I I pkp⁄( )2–--------------------------------×=
