The hazard of ice accretion on overhead power circuits is significant, yet predicting it is very difficult. The key reason lies in the shortage of sufficient observational data on ice thickness, and previous studies have also rarely taken into account micro-terrain and micro-meteorological conditions. In response to the challenge of simulating overhead line icing, this study introduces a new icing simulation technique that fully considers the effects of micro-terrain and micro-meteorology. For this technique, typical micro-terrains of overhead line areas are first identified by using high-resolution elevation data, and the icing thickness characteristics in different micro-terrains are analyzed. Subsequently, icing thickness simulations for different micro-terrains are conducted. The results indicate that during the icing process, the icing thickness ranges from 5 mm to 8 mm under three types of micro-terrain, namely, “uplift type”, “alpine drainage divide type” and “canyon wind channel type”, whereas the icing thickness is less than 5 mm in the “flat type” of micro-terrain. This finding suggests that the first three micro-terrain types facilitate icing on overhead transmission lines due to the condensation and uplifting effects of water vapor caused by terrain. However, flat terrain lacks the conditions necessary for water vapor accumulation and thus is not easy to form icing. The results are advantageous for the deployment of overhead power lines in intricate terrain. It is advisable to steer clear of regions susceptible to icing, and endeavor to install circuits in level territories whenever feasible. In addition, the simulated icing thickness under different terrains is in good agreement with the observations. Specifically, the correlation coefficient between simulated and observed icing thickness is significant at the 0.99 confidence level, and the deviations between them are within 0.5 mm. This signifies that the forecasting methodologies employed are dependable and possess significant implications as a reference for disaster prevention and mitigation efforts.

The overhead contact system of the electrification railway is exposed to the natural environment throughout the year and is liable to encounter the problem of line icing. The icing on the line will reduce the current-collection performance of the pantograph, resulting in a decrease in the safety and reliability of the overhead contact system. It is an effective way to solve the icing problem by using the Joule heat generated by the DC in the conductor to melt the ice. In this paper, the multi-physics simulation software COMSOL is used to construct the finite element simulation model of the overhead contact system unit composed of a contact line, catenary wire and dropper. The model covers the physical processes such as convective heat transfer between conductor and air, heat conduction between overhead contact system and ice layer during ice melting, and considers the latent heat factor of ice melting. Under the condition of no icing, the actual data of several temperature points are measured under the applied current state of the overhead contact system, and the validity of the model is verified by comparing the simulated temperature data with the measured data. On this basis, the effects of ambient temperature, ice thickness and current on ice melting were studied using simulations. The results show that the ambient temperature has a significant effect on the ice-melting speed. Under 10 mm ice thickness and 2 m/s wind speed conditions, the time to start melting ice increases from 2 to 60 min until the ice cannot be melted as the ambient temperature decreases from −1 °C to −25 °C. Various initial conditions for ice thickness and wind speed were analyzed. Under the condition of no ice, the temperature rise of the contact wire and the catenary wire increases significantly with the current increase. When the current increases from 500 A to 2000 A, the temperature rise of the contact wire increases from 9.08–9.25 °C to 214.07–218.59 °C, and the temperature rise of the catenary wire increases from 6.88–7.01 °C to 173.43–177.13 °C. In addition, there is an optimal ice thickness range for the ice-melting process. When melting ice at −1 °C and −5 °C, the optimal ice thickness ranges are 4–8 mm and 1–4 mm, respectively.

In recent years, extremely low-temperature weather conditions have resulted in the formation of ice on the contact network of electrified railways, significantly affecting the security of these systems. To address the issue of icing on the overhead contact system, this paper proposes a direct current–based ice melting system. This paper outlines the topological structure of the contact network ice melting system and examines its operational principles. A finite element model was established to investigate the characteristics of the ice melting process on the contact line, and a quantitative analysis was conducted to assess the impact of four critical variables: temperature, ice thickness, direct current, and conductor configuration. Ultimately, a simulation model of the contact line ice melting system for the traction power supply system was developed, and the output/input characteristics of the ice melting system were analyzed to validate its feasibility.