# Cable Temperature Prediction Based on RF-GPR for Digital Twin Applications
## 1 Introduction  
Under the goal of \"reaching the peak of carbon and carbon neutrality\", the construction of new power systems with new energy as the main body is the future development trend of power grids. Digital technology and intelligent application are the keys to support the construction of new power systems and the key technologies to achieve the safe and stable operation and intelligent maintenance of power equipment [1]. A digital twin is one of the key technologies to promote intelligent and digital development in the field of power equipment. Digital twin technology opens up the full-link process of the entity perception model application [2], realizes the comprehensive perception of the state of power equipment based on new sensor technology, and realizes sensor device evaluation and data in-depth governance according to the operation characteristics of power equipment. The digital twin power equipment model is built by big data analysis, data mining and other technologies to carry out the state differentiation evaluation, accurate fault diagnosis and accurate state prediction of power equipment and realize real-time interaction between the physical entity of power equipment and the digital twin, as well as information sharing between multiple digital twins of power equipment [3]. With the rise of the Internet of things and big data and the development of artificial intelligence and virtual reality technology, digital twin technology has received more and more technical support and engineering applications, mainly applied in intelligent agricultural production [4; 5], design and manufacturing in the automobile and aerospacefields [6], system development and operation [7], preliminary analysis and research in the field of power equipment [8; 9], etc. Ref. [10] proposed a method of integrating the DS simulation model and Manufacturing Execution System (MES) to create a digital twin model and proposed two frameworks of integrating the digital twin based on MES. Ref. [11] summarized and reviewed the current trends and limitations of digital twin applications in additive manufacturing and provides technical support and method reference for further research on digital twin systems. Ref. [12] showed the reliability and effectiveness of the twin model through the real-time simulation of the digital twin system of wind turbines and the twinning simulation of unmeasurable field data. Ref. [13] deeply and comprehensively discussed the technical route of the real-time online analysis system of the power grid and prospects the application scenarios of the next-generation real-time control system with the second-level response. Ref. [14] analyzed the similarities and differences between digital twinning technology and big data from many aspects and proposed technologies and methods for how to promote the realization of intelligent manufacturing. With the acceleration of the construction of the new power system network, the electrical connection between the transmission networks becomes closer and closer, and the security and stability of power transmission become more and more important. Currently, the electric energy transmission equipment in the power network framework of our country are mainly aerial lines and cable lines, while power cable is usually laid in the soil, tube galleries, tunnels and cable trenches, which have the advantages of being safe and stable, not occupying space and having high power transmission efficiency. In recent years, the proportion of power transmission efficiency has been increasing in the urban distribution network. Therefore, how to ensure the safe and reliable operation of power cables, as well as the accuracy of the monitoring and evaluation calculation results of key heating conditions such as the cable core, are hot issues in current research [15]. The calculation methods of cable temperature mainly include the numerical method and thermal method.