The dynamic response characteristics, including maximum jump height and unbalanced tension, of isolated‐span transmission lines after ice‐shedding are investigated by means of experiments. A reduced‐scale modelling method for ice‐shedding from conductor lines is presented and verified with numerical simulations and full‐scale test results in the literature. A parameter study on dynamic responses of isolated‐span conductors under three ice‐shedding scenarios, including whole span ice‐shedding, partial ice‐shedding and unzipping ice‐shedding, is carried out by means of reduced‐scale modelling tests. The effects of these parameters on the maximum jump height at typical positions and unbalanced tension in the tension tower are obtained. It is observed that the partial ice‐shedding scenario may be the worst situation for electrical insulation clearance rather than the whole span ice‐shedding scenario. Moreover, the position of maximum jump height along the span of isolated‐span transmission lines after ice‐shedding could be at around 2/5 of span length, which is different from the conventional opinion that the position is at the midpoint. The results may provide a foundation for the defining of the insulation clearance for an isolated‐span transmission line and the structure design of tension tower arms in an iced zone.

The risks of power supply in power systems attributed to stray currents caused by denser metro lines are increasing in modern megacities. Factors such as multi-layered soil and multiple metro operating lines (MOLs) make it more difficult to analyze dc coupling between the metro and power system. This article proposes a model for dc coupling of the metro and power system considering the two systems’ spatial information, the actual multi-layered soil, and the non-linear ionization of soil caused by stray currents. This article presents a dc coupling model suitable for studying multiple metro lines and large-scale power systems in modern megacities, which has an average relative error of 6.3% compared with experimental results. The neutral current of the transformer in a substation is up to 43 A (normal operation requires it to be less than 6 A in amplitude) under the influence of multiple MOL. The non-linear ionization of the soil near the power substations’ grounding network will decrease the soil resistance, this also results in greater dc currents intruding into power substations.

The pantograph-catenary system, serving as the ’throat’ for the energy supply of high-speed railways, inevitably experience current degradation caused by ice accumulation on the catenary when high-speed trains pass through areas with high relative humidity, low temperature, and high wind speeds. To explore the impact of the complex service environment on the growth process of catenary icing, this paper, based on the study of the mechanism of catenary icing, proposes an ice prediction method for catenary icing oriented to numerical model and deep learning. Firstly, based on the calculation of key parameters such as capture rate, freezing coefficient, and collision coefficient, a numerical model for catenary icing under time-varying meteorological conditions is developed. Secondly, study the impact of four factors, including wind speed, temperature, liquid water content (LWC), and median volume diameter (MVD), on the evolution of catenary icing. Finally, by integrating the convolutional neural network-long short-term memory (CNN-LSTM), a prediction model for catenary icing is established. The study addressed challenges such as unclear mechanisms of catenary icing, difficulties in detecting icing states, and insufficient sample data. It laid a theoretical foundation for icing forecasting and warning, selection of de-icing strategies, and research on the dancing of catenary icing.