Protecta lite is a Metal Oxide based conductor used in parallel to the normal insulator disc in Over Head transmission system. It protects the insulation disc from flash- over due the surge voltage by allowing an easy path to the ground.
The Ohio Brass Company's (Hubbell Power Systems) Protecta*Lite overhead line lightning protection system does that and a whole lot more.
I designed the first one for a 100 kV transmission line that served a critical industrial plant for Duke Power. The Protecta*Lite assemblies reduced the outages and momentary interruptions due to lightning and other overvoltages to near zero.