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3.7
Time delayed residual overcurrent protection
(TEF)
Technical data
Table 86:
TEF - Time delayed non-directional residual overcurrent protection
Parameter
Start current, definite time or inverse
time delay, IN>
Characteristic angles
Definite time delay
Time multiplier for inverse time delay
k
Normal inverse characteristic
I = I
/I
meas
set
Very inverse characteristic
Extremely inverse characteristic
Logarithmic characteristic
Min. operate current for dependent
characteristic, IMin
Minimum operate time for dependent
characteristic, tMin
Reset time
Setting range
Accuracy
± 5% of set value
5-300% of Ib in steps of
1%
± 5 degrees at 20 V and I
65 degrees lagging
of I
± 0.5 % +/-10 ms
0.000 - 60.000 s in steps
of 1ms
0.05-1.10 in steps of 0.01 According to IEC 60255-3
IEC 60255-3 class 5 ± 60 ms
IEC 60255-3 class 7.5 ± 60 ms
13.5
---------- - k ⋅
t
=
I 1
–
IEC 60255-3 class 7.5 ± 60 ms
± 5 % of t at I = (1.3-29) × I
I
⋅
---- -
t
5.8 1.35
ln
=
–
I
N
± 5% of I
100-400% of IN in steps
of 1%
± 0.5 % ± 10 ms
0.000-60.000 s in steps
of 1 ms
<70 ms
-
Chapter 5
Current
=35%
set
r
N
set
75
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