Temperature rise response and live assessment test of gas insulated transmission lines

Gas insulated transmission lines (GIL) operate under high voltage and high current conditions, and their temperature rise characteristics are influenced by the interaction of multiple physical fields. However, traditional GIL temperature rise analysis methods only consider the current magnitude and idealized simplified models, making their results insufficient to effectively determine whether GIL has abnormal temperature rise responses. To address this issue, this paper presents a study on the temperature rise characteristics of key GIL components based on a multi-physics coupling strategy. Firstly, a magnetic-thermal-fluid coupling theory is established, and the finite element and physical models of GIL are constructed, taking into account the effect of contact resistance at the contacts. Secondly, a steady-state temperature rise analysis under power frequency conditions is performed to reveal the temperature rise response patterns of key GIL components. Finally, the effectiveness of the models and temperature rise response conclusions is validated through live testing experiments. Based on the aforementioned foundation, this paper proposes a 220 kV GIL response correlation model, which relates the conductor temperature to the average temperature at the top of the enclosure and the operating current. By comparing the model results with experimental data, it is demonstrated that this model has high accuracy and can serve as an empirical calculation method for GIL conductor temperature in practical engineering applications.