GE Multilin
745 Transformer Management Relay
5-51
5 SETPOINTS
5.6 S4 ELEMENTS
5
IEC CURVES:
For European applications, the relay offers three standard curves defined in IEC 255-4 and British standard BS142. These
are defined as IEC Curves A, B, and C. The formula for these curves, where 1.03
≤
I
/
I
pickup
<
20.0, is:
(EQ 5.7)
where:
T
= Operate Time (sec.)
M
= Multiplier Setting
I
= Input Current
I
pickup
= Pickup Current Setting
K
, E = Constants
Table 5–7: IEC (BS) INVERSE TIME CURVE CONSTANTS
IEC (BS) CURVE SHAPE
K
E
IEC CURVE A (BS142)
0.140
0.020
IEC CURVE B (BS142)
13.500
1.000
IEC CURVE C (BS142)
80.000
2.000
IEC SHORT INVERSE
0.050
0.040
Table 5–8: IEC CURVE TRIP TIMES (IN SECONDS)
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 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
T
M
K
I
I
pickup
----------------
E
1
–
----------------------------------
×
=
Содержание TRANSFORMER MANAGEMENT RELAY 745
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