»нженер электрик

Ќова€ верси€ сайта.  ликни!
»нформации в 10-ки раз больше

-???-

-???-


Current loads

English > Tests

–усский




Current loads in operating mode

Permissible current loads for cables in operating mode are calculated for the following conditions:

Ц maximum conductor temperature 90 ∞—;
Ц ambient temperature 15 ∞—at laying in ground,and 25 ∞—Ц at laying in free air;
Ц depth of laying in ground is 0.8 m for cables for rated voltage up to 35 kV, and 1.5 m Ц for cables for rated voltage of 110 kV;
Ц thermal resistance of soil is 1,2 ∞KЈm/W.

At other ambient temperatures the permissicurrent loads shall be multiplied by the corfactor as it is indicated in the tables below (for cables from 6 kV to 35 kV):

The correcting coefficients k1 for the temperature of the surrounding air other than 30 ∞C
(the maximum temperature of the core is 90 ∞C).


Correction coef≥cient at the environment temperature, ∞—

20

25

35

40

45

50

55

60

1.08

1.04

0.96

0.91

0.87

0.82

0.76

0.71


The correcting coefficients k1 for the temperature of the surrounding air other than 20 ∞C
(the maximum temperatuof the core is 90 ∞C)

Correction coef≥cient at the environment temperature, C

10

15

25

30

35

40

45

50

1.07

1.04

0.96

0.93

0.89

0.85

0.8

0.76


At cable laying in trefoil the distance between the axis of cable is equal to the cable outer diameter, at laying of three cables in flat formation the distance between axis of the cabis equal to two cable diameters.


Return to contents

яндекс.ћетрика

-???- | -???-