Browse > Article
http://dx.doi.org/10.14481/jkges.2011.12.1.2

Development of Environmentally Friendly Backfill Materials for Underground Power Cables Considering Thermal Resistivity  

Kim, Daehong (KEPCO 전력연구원)
Oh, Gidae (KEPCO 전력연구원)
Publication Information
Journal of the Korean GEO-environmental Society / v.12, no.1, 2011 , pp. 13-26 More about this Journal
Abstract
Because the allowable current loading of buried electrical transmission cables is frequently limited by the maximum permissible temperature of the cable or of the surrounding ground, there is a need for cable backfill materials to be maintained at a low thermal resistivity during the service period. Temperatures greater than $50^{\circ}C$ to $60^{\circ}C$ may lead to breakdown of cable insulation and thermal runaway if the surrounding backfill material is unable to dissipate the heat as rapidly as it is generated. This paper describes the results of studies aimed at the development of backfill material to reduce the thermal resistivity. A large number of different additive materials were tested to determine their applicability as a substitute material. The results of Dong-rim river sand (relatively uniform) show that as water content level increases, thermal resistivity tends to decrease, whereas the thermal resistivity on dry condition is very high value($260^{\circ}C-cm/watt$). In addition, other materials(such as Jinsan granite screenings, A-2(sand and gravel mixture), E-1(rubble and granite screenings mixture) and SGFC(sand, gravel, fly-ash and cement mixture)) are well-graded materials with low thermal resistivity($100^{\circ}C-cm/watt$ when dry). Based on this research, 4 types of improved materials were suggested as the environmentally friendly backfill materials with low thermal resistivity.
Keywords
Underground power cables; Thermal resistivity; Backfill materials; Granite screenings; SGFC;
Citations & Related Records
연도 인용수 순위
  • Reference
1 Blackwell, J. H.(1956), A Transient-flow Method for Determination of Thermal Constants of Insulating Material in Bulk, Journal of Applied Physics, Vol. 25, No. 2, pp. 137-144.
2 Boggs S. A., Chu, F. Y., Radhakrishna, H. S. and Steinmanin, J. E.(1981), Underground Cable Thermal Backfill, Proceedings of the Symposium on Underground Cable Thermal Backfill, Toronto, Canada, pp. 37-56.
3 Carlslaw, H. S. and Jaeger, J. C.(1959), Conduction of Heat in Solids, 2nd Edition, Oxford University Press, New York, pp. 137-256.
4 de Vries, D. A. and Peck, A. J.(1958), On the Cylindrical Probe of Measuring Thermal Conductivity with Special Reference to Soils, Aust. Jour. Physics., Vol. 11, No. 2, pp. 255-271.   DOI
5 Fukagawa, H., Imajo, T. and Ogata, N.(1974), Thermal Diffusion and its Application to Cable Ampacity, CRIEPI-73087, pp. 25-85.
6 Hopper, F. C. and Lepper, F. R.(1950), Transient Heat Flow Apparatus for the Determination of Thermal Conductivities, Heating piping and Air Conditioning, ASHVE J. Sect., Vol. 24, No. 10, p. 464.
7 Horrocks, J. K. and McLanughlin.(1963), Non-steady State Measurements of Liquid Polyphenyls, Proc. Roy. Soc. Lond., Ser. A, Vol. 273. pp. 34-45.
8 Imajo, T.(1976), Development of Backfill Soils for Underground Cables(2) - Study on the Optimum Grading Distribution, CRIEPI- 72061, 175063, pp. 121-145.
9 Mitchell, J. K. and Chan, C. K.(1982), Backfill Materials for Underground Power Cables, Phase 1-3, EPRI EL-506, EL-1894, EL-4150, pp. 37-45.
10 Wiseman, R. J. and Burrel, R. W.(1969), Soils Thermal Characteristics in Relation to Underground Power Cable, AIEE Committee Report, Transaction of AIEE, Vol. 79, pp. 792-856.