We proposes the new concept "relay agent" to realize a cooperative protection system, which consists of distributed equipment combined with a communication network to cooperate in realization of adaptive protection functions. Relay agents move between equipment to utilize data and functions distributed over the power system. In the paper, relay agents are classified by their roles, and protection functions under some typical conditions are simulated. Consideration based on the simulations indicate that the concept enables the protection system to keep an isolated zone minimum against any changes in power system conditions and to secure high reliability of the protection system with less redundant hardware. The new concept "relay agent" will provide a powerful means of advanced protection functions by combination of micro processor technology and information communication technology.
ASJC Scopus subject areas