In Yun-Guang HVDC system, the converter transformer protection is not redundant, the reason is that the CT configuration of converter transformer bushing is not enough. This paper proposes an improved method to solve the problem of non-redundancy of converter transformer protection. Considering the structural features of converter transformer, i.e Y/Y wiring and Y/△wiring parallel connection, this mothod changes CT secondary wiring connection of converter transformer bushing, cooperates it with CT of converter transformer feeder breaker, and modifies the corresponding protection criterion. Thus the protection dual configuration problem caused by insufficient configurations of converter transformer bushing CT and neutral point CT is improved. The protection device before/after improving is tested on RTDS, the results show that the improved protection performance is increased to some extent and can basically solve the non-redundant problem.