Figure. 5.3.19 - 157. Set correction curve for ambient temperature.
The correction curve for ambient temperature is shown in the figure above. The reference temperature
for underground cables is u15
̊
C which gives a correction factor of 1.00 (in this case also the
nominal temerature). The curve does not need to use as all the available points. The minimum setting is
two pairs, resulting in a straight line.
For cables the ambient temperature correction is just one correction factor. The k
SF
correction factor is
used for non-changing corrections; its calculation is explained later in this manual. Calculating
correction factors for a cable or overhead installation requires the consulting of the datasheet for the
technical specifications of the used cable. This information is usually provided by the cable
manufacturer. For example, cable data may be presented as in the figures below (an example from a
Prysmian Group cable datasheet) which show the cable's temperature characteristics and voltage
ratings (1st image) with different installations and copper or aluminum conductors (2nd and 3rd
image).
A
AQ
Q-F205
-F205
Instruction manual
Version: 2.04
© Arcteq Relays Ltd
IM00013
221
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