Lightning Overvoltages on Hybrid Overhead Lines (Invited Lecture)

The CIGRE Working Group (WG) C4.67 (Lightning Protection of Hybrid Overhead Lines) started its activities in January 2022. The main objectives of the WG are to assess the overvoltages caused by direct and indirect strokes on hybrid overhead lines and to analyze the lightning performances of their distribution circuits, making comparisons with conventional distribution circuits alone. It also aims to provide guidelines for the safety of persons and protection of equipment in low-voltage networks supplied by hybrid overhead lines, as well as assess the lightning overvoltages on typical multi-circuit transmission lines with different rated voltages and protection methods. This paper presents some results obtained so far, with emphasis on the overvoltages associated with direct strokes to an existing hybrid overhead line obtained by calculations using the Electromagnetic Transients Program (EMTP) and measurements performed on a 1:20 scale model. The good agreement between measured and calculated voltages validates the computational and experimental models developed for the investigations.