Evaluation of High Surge Impedance Loading (HSIL) solutions for increased natural capacity of 500 kV Overhead Lines

This report compares six different 500kV Transmission Lines Projects, each with four subconductors per phase and Surge Impedance Loading (natural capacity) of 1200 MW, which are currently operating in more than 10.000 km of extension in Brazil. Transmission Line compaction and the use of expanded bundle techniques are analyzed focusing on electrical coupling and its influence on positive sequence and zero sequence impedance. The electric field on the conductors' surface and the electric and magnetic fields at ground level are evaluated for each configuration.