To date, synchronized phasor measurements have been used mainly for power system model validation, post-event analysis, real-time display, and other similar activities. However, synchrophasors have a greater potential than monitoring and visualization. Synchrophasors will increasingly contribute to the reliable and economical operation of power systems as real-time control and protection schemes become broadly used. This paper describes several synchrophasor-based protection and control systems. One of these systems uses synchrophasor information for generator shedding. The other system uses synchrophasors for backup transmission line protection for ground faults. In addition, the paper describes a user-programmable, real-time synchrophasor processor and two of its applications: a distributed bus differential protection scheme and a system integrity protection system.