Report on the heat resistance of the bedding material 110kV cable (Kamenolom Krizice)

Abstract

The transmission capacity and lifespan of power cables, and thus the quality and reliability of power supply to consumers, directly depend on the ability of the environment to dissipate the heat that develops due to Joule and dielectric losses in the cable. The excess temperature of an underground power cable is proportional to the specific thermal resistance of the environment in which the cable is laid. For common geological environments, the thermal resistance ranges from 40 Kcm/W to 400 Kcm/W. A well-chosen and dimensioned cable bedding can significantly improve heat dissipation from the cable surface and thus extend its lifespan, just as a poor bedding can lead to its overheating and premature destruction. Therefore, it is necessary to investigate the thermal properties of the bedding material before application. The thermal resistance of the tested sample usually depends on its wetness and charge (density). A completely wet compacted sample (8.2% water) shows a thermal resistance of 69 K cm/W, and a dried compacted sample of about 240 K cm/W. A moderately dry sample (from 2% to 8% water) has a resistance of about 75 K cm/W, so it can be recommended as a suitable material for a cable tray.

Stanko Milun

Full Professor

Faculty alumnus with a research focus in the development of measurement methods in high-voltage systems, signal analysis in electrical power systems, and the application of geoelectrical methods in energy infrastructure. Prof. Milun has been involved in numerous scientific projects, including those related to the optimization of grounding systems for high-voltage plants and the development of transient measurement methods. He has authored 38 scientific papers and over 150 professional studies.

Goran Petrović

Full Professor | Department of Electrical Measurements

Prof. dr. sc. Goran Petrović is a full professor at the Faculty of Electrical Engineering, Mechanical Engineering and Architecture in Split. His research interests include measurement of electrical and process quantities, analysis of geoelectrical and geothermal features of the soil, instrumentation for smart grids, measurement and application of synchrophasors. He is the author of numerous papers published in top-tier scientific journals and contributed to valuable international and national scientific projects.