The photo is from existing 345kV and 500kV guyed tower foundations. Structures on the left are on a new 500kV circuit and those on the right are on a 20 year old 345kV circuit.
Structure-to-soil potential measurements on guyed anchors and tower foundations on the 345kV circuit showed that cathodic protection had failed on some of the towers due to incompatible selection of anode material for the soil environment. Other structures were not protected simply due to exceeding the useful design life of the anodes.
Recommendations were made for replacement anodes, where necessary on the 345kV circuit. A comprehensive cathodic protection design was furnished for the 500kV circuit.[...]
