The protection simulation plays an important role in the centralized control substation (CCS) training system. This paper thoroughly analyzes the different features of CCS protection simulation that contrast with those of the DTS one. The protection simulation is proposed based on expansion of the former DTS. An improved protection model that takes into account the database’s stability is presented to satisfy the demand of diversified protection set layout. A new autodrawing technique is developed for reducing the difficulty in protection set picture drawing. By the detachability of the variable protection switch simulation from other protection simulation

the simulation algorithm can keep the hierarchical structure stable with any complex protection switch set. The practicability and expandability of the protection simulation have been validated by onthespot implementation.