GE D90 Plus Instruction Manual page 243

CHAPTER 7: PROTECTION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
IAC curves
The curves for the General Electric type IAC relay family are derived from the formulae:
where
• T = operate time (in seconds)
operate
• TDM = multiplier setting
• I = input current
• I = pickup current setting
pickup
• A to E = constants defined in the table
• T = reset time in seconds (assuming the energy capacity is 100% and the reset
reset
mode is "Timed")
• t = characteristic constant defined in the table
r
Table 10: GE type IAC inverse time curve constants
IAC curve shape A
IAC Extreme Inverse 0.0040
IAC Very Inverse 0.0900
IAC Inverse 0.2078
IAC Short Inverse 0.0428
Table 11: GE type IAC curve trip times (in seconds)
Multiplier Current (I / I
pickup
(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 4.846
10.0 33.979 14.983 6.058
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 4.299
10.0 29.012 13.121 5.374
IAC Inverse
0.5 0.578 0.375
1.0 1.155 0.749
B C
0.6379 0.6200
0.7955 0.1000
0.8630 0.8000
0.0609 0.6200
)
3.0 4.0 5.0 6.0
0.303 0.178 0.123 0.093
0.606 0.356 0.246 0.186
1.212 0.711 0.491 0.372
2.423 1.422 0.983 0.744
3.635 2.133 1.474 1.115
2.844 1.966 1.487
3.555 2.457 1.859
0.269 0.172 0.133 0.113
0.537 0.343 0.266 0.227
1.075 0.687 0.533 0.453
2.150 1.374 1.065 0.906
3.225 2.061 1.598 1.359
2.747 2.131 1.813
3.434 2.663 2.266
0.266 0.221 0.196 0.180
0.532 0.443 0.392 0.360
GROUPED PROTECTION ELEMENTS
D E t
r
1.7872 0.2461 6.008
–1.2885 7.9586 4.678
–0.4180 0.1947 0.990
–0.0010 0.0221 0.222
7.0 8.0 9.0 10.0
0.074 0.062 0.053 0.046
0.149 0.124 0.106 0.093
0.298 0.248 0.212 0.185
0.595 0.495 0.424 0.370
0.893 0.743 0.636 0.556
1.191 0.991 0.848 0.741
1.488 1.239 1.060 0.926
0.101 0.093 0.087 0.083
0.202 0.186 0.174 0.165
0.405 0.372 0.349 0.331
0.810 0.745 0.698 0.662
1.215 1.117 1.046 0.992
1.620 1.490 1.395 1.323
2.025 1.862 1.744 1.654
0.168 0.160 0.154 0.148
0.337 0.320 0.307 0.297
Eq. 14
Eq. 15
233