Influence of Bundle Conductors in UHV Transmission Lines

This paper aims to study the surface gradient potential (SGP) of overhead line conductors in ultra-high voltage (UHV) transmission lines. The SGP is crucial for the performance due to the corona effect. The purpose is to assess the calculation of the gradient of bundle conductors and the main factors that influence this calculation. It is accomplished a critical analysis of the main analytical and numerical existing methods. In addition to that, it is presented a study of special conductors concerning the application of both new materials and innovative wire stranding. The successive images numerical method is applied to the study and verified the accuracy for transmission lines with multiple bundle conductors. The methodology is evaluated by considering numerical simulations on a 1000 kV AC transmission line. The partial results indicate that gradient distribution is sensitive to bundle spacing and different bundle arrangements. The latter being the most influential. In view of these results, it is recommended to use numerical methods based on finite elements to better evaluate the surface gradient. This adequate method enables simulations of multiphysics problems regarding different geometries.