Ground relay system in a multiplex direct grounding system

摘要

A ground relay system is provided which includes: first current transformers located in the respective phases of a sending end of a high-voltage distribution provided from a distribution substation; over-current relays connected to the first transformers; distribution transformers located in the respective phases in the respective sections of the distribution; second current transformers connected to secondary sides of the distribution transformers; current converters connected to the second transformers; and a current comparator that introduces the currents of the respective phases of the sending end of the distribution from the relays to produce a first zero-phase current, introduces the currents of the respective phases of a load end of the high-voltage distribution from the current converters to produce a second zero-phase current, and operates a ground protection relay that opens a circuit breaker inserted at the sending end of the high-voltage distribution if the level of the first current is larger.