Design of evaporative cooling systems for high voltage cables
Design of evaporative cooling systems for high voltage cables
The design and analysis of a method of cooling underground cables by the evaporation of a suitable coolant is presented. Two coolants are investigated, Freon-12 and Water. By the use of a reservoir of a given height a natural convection flow through the conductor internal ducts of the cables is set up without the need for pumps as used in forced cooling techniques. A detailed analysis involving coolant flow rate, coolant reservoir height, cooled length of cable, duct size and cable loss is presented and incorporated in several computer programs. This has resulted in the development of sets of master graphs by means of which a system may be designed. The effects of sudden changes in load and overloads are investigated and it is seen that the thermal conditions change rapidly. A maximum current rating for the cables is discussed which must not on any account be exceeded because of the likelihood of burnout in the cooled duct. The possibility of evaporative cooling of the outside surface of the cables (integral cooling) is investigated and is seen to have great limitations compared with the conductor duct method. The use of water as a coolant is seen to have considerable design and operating problems compared with Freon-12. Ratings obtainable with evaporative cooling are compared with conductor duct forced cooled schemes using water or oil. It is seen that the ratings for water (water cooled) and evaporative cooling (Freon-12) are similar and much higher than those for oil.
University of Southampton
De Lima, Francisco Ronaldo Frazao
1980
De Lima, Francisco Ronaldo Frazao
De Lima, Francisco Ronaldo Frazao
(1980)
Design of evaporative cooling systems for high voltage cables.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The design and analysis of a method of cooling underground cables by the evaporation of a suitable coolant is presented. Two coolants are investigated, Freon-12 and Water. By the use of a reservoir of a given height a natural convection flow through the conductor internal ducts of the cables is set up without the need for pumps as used in forced cooling techniques. A detailed analysis involving coolant flow rate, coolant reservoir height, cooled length of cable, duct size and cable loss is presented and incorporated in several computer programs. This has resulted in the development of sets of master graphs by means of which a system may be designed. The effects of sudden changes in load and overloads are investigated and it is seen that the thermal conditions change rapidly. A maximum current rating for the cables is discussed which must not on any account be exceeded because of the likelihood of burnout in the cooled duct. The possibility of evaporative cooling of the outside surface of the cables (integral cooling) is investigated and is seen to have great limitations compared with the conductor duct method. The use of water as a coolant is seen to have considerable design and operating problems compared with Freon-12. Ratings obtainable with evaporative cooling are compared with conductor duct forced cooled schemes using water or oil. It is seen that the ratings for water (water cooled) and evaporative cooling (Freon-12) are similar and much higher than those for oil.
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Published date: 1980
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Local EPrints ID: 459124
URI: http://eprints.soton.ac.uk/id/eprint/459124
PURE UUID: db81d8a7-22a7-4817-9d6d-bebec9b7261d
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Date deposited: 04 Jul 2022 17:04
Last modified: 04 Jul 2022 17:04
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Author:
Francisco Ronaldo Frazao De Lima
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