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Figure. 5.4.21. - 98. Settings of the TOLF function ambient temperature coef cient curve.
Temperature and coef cient pairs are set to the TOLF function settable curve.
Table. 5.4.21. - 161. Set correction curve for ambient temperature.
The correction coef cient curve for ambient temperature
is shown in the gure.
The reference temperature for ground dug cables usually
is 15
̊
C which gives correction coef cient of 1.00 which
can referred as nominal temperature in this case.
The curve does not need to be set as many points as
there is available. Minimum setting is two pairs and the
result will be straight line.
For the cables this ambient temperature correction is just one correction parameter. For the non-
changing corrections are used k
SF
correction factor which calculation is explained in following part. To
calculate the correction factors for the cable or overhead installation, there is need to consult the
technical speci cation for the initial data of the cable used. This information is usually provided by the
cable manufacturer.
For cable the initial data may be as follows (example data from Prysmian cables datasheet).
AQ-F255
Instruction manual
Version: 2.00
169
© Arcteq Relays Ltd