Study Of Communications In Wide Area Protection Systems

With the increasingly enlargement of electric network scale and the fast development of interconnected network, power system protection and stability control are becoming more and more important. Based on modern communication technology and wide-area measurement system (WAMS), wide-area protection system (WAPS) has been paid much attention since it is proposed in the end of twentieth-century. It finds a new way to deal with coordination issue between relaying protection system and automatic safety device in large power system. It leads the development of relaying protection in the future.In order to coordinate devices installed all over the power system, information from each point is needed, including electric measurements, actuating signals and network topological structure, which is the foundation of WAPS can be actualized.With the development of computer and communication, First, the WAPS structure and the characteristics of data type in power system are summarized. And then the communication delay which WAPS demands is analyzed, which is quite important to put forward wide-area protection system communication system scheme. Present communication technique which is adapt to WAPS is analyzed, including IP switching, Multi Protocol Label Switching(MPLS) technique etc. Then discuss the communication means, such as communication physical media, communication mode etc., to find the scheme which is applicable to WAPS. Finally, based on MPLS technique, the new WAPS communication system scheme is put forward in the paper. And the communication performance about real-time ability and reliability is simulated by OPNET software. By comparing the old and the new communication system performance, the new communication system scheme meets the demand of the WAPS. The result of this paper is helpful to planning wide-area communication system.