Wide-area relay protection system

In this paper,the research status and development direction of wide area relay protection in our country are reviewed.With the construction of supper interconnection in nationwide,the gradual application of power market mechanism and other factors as well,the protection system is facing more new challenges.The article introduces the development situation and the structure of wide-area protection system.An illustration of protection arithmetic based on graph theory is proposed to explain the division and definition of protection area.At last the network and the agreements of communication are introduced.