Rating of Pipe-Type Cables With Slow Circulation of Dielectric Fluid

This paper presents a new rigorous approach to the calculation of current ratings in pipe-type cables with slow circulation of the fluid. Detailed mathematical analysis is presented for the calculation of the hot-spot fluid temperature as a function of the cable geometry and the fluid inlet temperature. The emphasis is placed on real-time applications, in which the pipe-surface temperature is measured. A numerical example from an actual cable installation is presented. A comparison with the commonly applied method based on Buller's model is offered.