Relaying the Keystone 500-kY System

The brief description and diagrams of system arrangement will familiarize the reader with the Keystone System, an entirely new 600-mile 500-kV transmission system without series capacitors or shunt reactors. Background infornation on the relay requirements and the features of the "local-backup" scheme provide a basis for understanding the protection applied to the individual equipments. Of significance is the investigation of the relay communication systems and the choice of power-line carrier for this function. Transient stability studies are discussed, and the clearing times effected to best meet the high-speed tripping requirements are included. Automatic reclosing, which was designed to meet the specific system requirements, is described in some detail. The automatic oscillograph coverage outlined may be one of the first designed and applied on a system basis.