Arcteq AQ-F210, Инструкция по эксплуатации

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Instruction manual –AQ F210 Feeder Protection IED 127 (292
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so the settings would be then In = 680 A, Tmax = 90 ̊C, Tamb = 15 ̊C, Tref = 15 ̊C and
k
SF
= 0.81
Now when trying to load the
cable with the given nominal
current can be seen that the
actual cable current carrying
capacity is much lower than in
presumption conditions. Normal
loading current can now get the
cable too warm and endanger its
withstandability. If in this case
the k
SF
factor would not been set
the thermal image would show
about 68 ̊C temperature when it
in reality would be 96 ̊C.
Figure 4.2.8-53 Thermal image response with nominal currents and fine tuned k
SF
correction factor.
When the installation conditions
vary from the presumption
conditions like in this example,
the current carrying capacity of
the cable had been reduced so
that 90 ̊C temperature is
achieved already with 550A
current instead of the initial data
given current of 680A.
Figure 4.2.8-54 Thermal response with k
SF
factor correctly set.