A Current Differential Relay System Using Fiber Optics Communications

Relay systems have made use of metallic circuits for communications entering the power station environment. These circuits have at times affected the system reliability due to extraneous voltage influences. The system described makes use of a unique fiber optic channel in place of the metallic circuit. The system takes advantage of the glass fiber´s virtual immunity to the effect of extraneous voltages. The relay system also uses new techniques for its sequence network and its current comparison method. These improvements increase the relay system reliability and broaden the area of application.