Abstract: Analyzed the TA configuration and merging unit setting on the 500 kV circuit breaker bushing, thought that 500 kV TA protection dead zone existed problems in original configuration scheme, while internal fault occurred in the 500 kV circuit breaker.A new solution was given.The new merging units were not used, but each group of TPY windings was configured with one unit of independent merging units.In the new plan, the primary equipment, the merging unit and the protective device were completely separated, without sharing equipment, and the reliability was one times higher than the original scheme.This scheme had been successfully applied in Baotou 500 kV intelligent substation in west Inner Mongolia.