Rapid Transfer Matrix-Based Calculation of Steady-State Temperature Rises in Cable Ducts Containing Groups of Three Phase Cable

This paper presents a heat transfer matrix and superposed thermal field-based method that can rapidly calculate steady state temperature rises in three-core cable groups laid in ducts. The temperature rise of any cable is a combination of self-reaction and interaction from other cables. A heat transfer matrix is formed by self-reaction coefficient and interaction transfer coefficient representing the thermal characteristics of the cable groups in ducts. The heat transfer matrix can be obtained by enough samples including temperature rise and cable losses based on numerical analysis, trial or commercial software. Rapid calculations can then be performed by simplify iteration of temperature-loss. Extraction of the transfer matrix using CYMCAP ampacity and temperature calculation software and application of the fast calculation method are illustrated and compared, confirming the feasibility and relative simplicity and accuracy of the fast calculation method.