Electrothermal Model of an AC Catenary and Mechanisms of Ice Melting under an Autotransformer Traction Power Supply System

Objective: to develop an electrothermal model for melting ice accretions on the catenary system of an electrified railway under an autotransformer traction power supply system, taking into account non-uniform icing and the thermophysical properties of the multilayer system “conductor — air gap — ice — ambient environment”. Methods: to investigate the melting process, a two-dimensional transient thermal model of the cross-section of the “conductor — air gap — ice — ambient environment” system was developed. Heat sources were defined according to the Joule — Lenz law for a prescribed heating current, phase change was incorporated using the equivalent heat capacity method, and external heat losses were described by radiative-convective heat transfer. Numerical simulation of the temperature field was performed using the finite element method. Results: it was established that electrothermal melting of ice accretions leads to the formation of a non-uniform temperature field caused by sequential heat transfer from the conductor to the ice layer through the air gap. It was shown that geometric non-uniformity of icing modifies the heat-transfer boundary conditions and causes differences in the thermal response of the system elements, thereby determining the spatial characteristics and kinetics of the melting process. Practical significance: the developed model can be used to analyze thermal regimes for de-icing overhead wires and to evaluate the energy parameters of melting processes. The results obtained allow us to clarify the physical mechanism of electrothermal melting of ice deposits and can serve as a basis for further research into overhead wire de-icing processes.