Extreme weather incident experienced on 765 kV line in South Africa

The performance of the 765 kV overhead line network in South Africa is generally good; however, faults do occur and are mainly attributed to lightning, veld fires, birds, and weatherrelated events. The predominant suspension tower type on the 765 kV network is a guyed-V suspension structure utilising V-string suspension assemblies that support a hexagonal ACSR conductor bundle. These guyed V-suspension structures have occasionally experienced guy anchor corrosion, particularly where lines traverse areas close to salt pans. Due to the original design of the guy anchors, the steel is exposed and in direct contact with the soil. In combination with the presence of small stray currents in the guy wires, this results in gradual corrosion and degradation of the metal anchors over time. Incidents…