The Effect of soil temperature on the ampacity values of underground cables in Jalingo, North – East Nigeria
ampacity values of underground cables in Jalingo
Keywords:Ampacity, Thermal Conductivity, Backfill, Ambient Temperature, soil, Jalingo
Cables are like bridges that connects the machine that generate electricity and the appliances that uses it. Electrical cable can be a single conductor (solid or stranded) insulated through its full length; or several conductors spread together with each given its insulation under one outer protective covering. Electricity flowing in a conductor generates heat. A resistance to heat flow between the cable and the ambient environment causes the cable’s temperature to rise. This work examined the effect of soil temperature on the current rating of a Cross Link Polyethylene Low Voltage Cable laid in three power substations in Jalingo, Taraba State. The findings revealed a mean soil temperature and ampacity value of 95.25 oC and 245.12 A for coarse soil, 95.06 oC and 318.90 A for clay soil and 94.8 oC and 318.70 A for loamy soils. Comparison of the ampacity values of the different soils with the standard value of 320 A, the current rating of the cable is reduced by 74.88 A, 1.1 A and 1.3 A respectively for coarse, clay and loamy soils. Results also indicated that the current rating of the cables laid on loamy soil is 1.3 times greater than that on coarse soil at their respective temperatures. The study suggested that clay and loamy soil are suitable materials for local backfilling, while coarse soil is not.
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