Insulated Overhead Ground Wires - Protective Carrier Relaying Investigations

The results of an extensive field investigation of the use of a single insulated overhead ground wire for protective carrier relaying are summarized and discussed. Transfer-trip relaying channels using either a single, continuous insulated ground wire or short insulated sections at each end of the line as carrier couplers are shown to be practicable. Balanced-pair operation of two insulated ground wires was not studied in field, however, the reliability for transferred-trip line protection is inferred to be poor.