CHAPTER 7: PROTECTION
GROUPED PROTECTION ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
229
IAC curves
The curves for the General Electric type IAC relay family are derived as follows.
Eq. 14
Eq. 15
The terms in the above equations are defined as follows.
•
T
operate
represents the operate time in seconds.
•
TDM represents the multiplier setting.
•
I
represents the input current.
•
I
pickup
represents the pickup current setting value.
•
A
to
E
are constants and are defined in the table below.
•
T
reset
represents reset time in seconds, assuming the energy capacity is 100% and the
reset mode is timed.
•
t
r
represents the characteristic constant and is defined in the table below.
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 time
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
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
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