5-258
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS
CHAPTER 5: SETTINGS
5
T = operate time (in seconds)
TDM = Multiplier setting
I = input current
I
pickup
= Pickup Current setting
K, E = constants defined in the table
t
r
= characteristic constant defined in the table
T
RESET
= reset time in seconds (assuming energy capacity is 100% and
RESET
is “Timed”)
Table 5-31: IEC (BS) inverse time curve constants
Table 5-32: IEC curve trip times (in seconds)
IEC (BS) curve shape
K
E
t
r
IEC Curve A (BS142)
0.140
0.020
9.7
IEC Curve B (BS142)
13.500
1.000
43.2
IEC Curve C (BS142)
80.000
2.000
58.2
IEC Short Inverse
0.050
0.040
0.500
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