Integrated backup protection scheme in modern power system

Backup protection is indispensable, particularly as a remote backup protection of neighboring devices. Since the distance protection only depends on local information, which is easy to implement and has stable performance, distance protection is regarded as backup protection of transmission lines. Unfortunately, the backup protection has played a negative role during the blackouts, and sometimes caused the cascading tripping. Therefore, it is necessary to re-recognize the role and the scheme of backup protection. This paper presents an integrated backup protection scheme, which integrates all backup protection of equipments in the same substation in one device or system. And all protections to equipment only contain the main protection. Such scheme can constitute backup protection with better performance and effectively reduce the scope of the blackout.