In recent years, information technology has been developed and applied to various manufactural fields. In this paper, we present information technology application to the protection relay system in the electric power system.
We restructured the protection relay system as the decentralized network system by using Ethernet. we proposed the method of synchronization control and real time communication on Ethernet in order to achieve high accuracy of data sampling synchronization and high response speed. In performance test, it was confirmed that the proposed system could meet the requirement of the protection relay system.