GE F35

5-230 F35 MULTIPLE FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS CHAPTER 5: SETTINGS
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 Curve A, IEC Curve B, and IEC Curve C. The IEC curves are derived by the operate and reset time
equations.
Eq. 5-9
where
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 5-29: IEC (BS) inverse time curve constants
Table 5-30: IEC curve trip times (in seconds)
10.0 64.390 38.032 24.322 19.458 16.883 15.255 14.117 13.267 12.604 12.068
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
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