A novel method for fast computation of the temperature rise and optimal design of GIL based on thermal network model

Accurate and fast computation of the temperature rise of gas-insulated transmission lines (GIL) is of great significance to its efficient operation and optimal design. This study proposes a novel method for efficient and accurate computation of the temperature rise and optimal design of GIL based on the thermal network method (TNM). The proposed TNM considers different heat transfer processes between the upper and lower parts of the GIL and the corresponding thermodynamic differential equations are derived. When applied to numerical simulation of GIL, the TNM can save more than three orders of magnitude in computational time compared to computational fluid dynamics (CFD) simulations, and good agreement with experimental data is also achieved. Then a fast optimal design model for GIL current-carrying structures is established based on the TNM, where it is convenient to consider factors including temperature rise and cost objectives, as well as electrical and mechanical field constraints. This optimal design approach circumvents the highly time-consuming electromagnetic-thermal-fluid coupled numerical computations. It is concluded that the proposed TNM provides an accurate way for temperature rise calculation and optimal design of GIL with really high efficiency.