Temperature mapping model of cables considering the coupling of electromagnetic and thermal field

Abstract

Background During cable operation, its internal temperature reflects the actual working condition of the cable. Once overload occurs, its conductor temperature will rise rapidly. Under high temperature conditions, the insulation material is very prone to breakdown accidents, which seriously threatens the safety of the power system. The traditional method of calculating the internal temperature of cables suffers from low accuracy and time-consuming problems. Methods To quickly and accurately calculate the cable’s internal temperature, a cable temperature mapping model is proposed with the coupling of electromagnetic and thermal field taken into consideration. Firstly, a finite element model is formulated based on the cable structure and material parameters. Secondly, the coupling between electromagnetic and thermal field is analyzed, and multiple coupling calculations are performed iteratively according to the operating conditions. Finally, the mapping between temperature and current is established using the exponential function. The cable surface temperatures under five operating conditions are measured online and compared with the calculated results of the temperature mapping model. Results Under five operating conditions, the average absolute error of the proposed model is 0.628 °C, and the average calculation time is 0.005 s. The average absolute error of the traditional model is 0.635 °C, and the average calculation time is 201.86 s. Conclusions The temperature mapping model developed in this paper can quickly and accurately calculate the cable’s internal temperature and forms an important part of the digital twin model of the cable.