GE D90 Plus Instruction Manual page 199

CHAPTER 7: PROTECTION
IAC curves
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
The curves for the General Electric type IAC relay family are derived as follows.
The terms in the above equations are defined as follows.
• T represents the operate time in seconds.
operate
• TDM represents the multiplier setting.
• I represents the input current.
• I represents the pickup current setting value.
pickup
• A to E are constants and are defined in the table below.
• T represents reset time in seconds, assuming the energy capacity is 100% and the
reset
reset mode is timed.
• t represents the characteristic constant and is defined in the table below.
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. 12
Eq. 13
191