A novel communication network for three-level wide area protection system

Wide area protection is the system protection against the electric power system wide area disturbance based on the modern measurement and communication technology. The three-level structure is a good structure for wide area protection system (WAPS), but it relies on high-performance communication system. The purpose of this paper is to design a suitable communication network for the three-level WAPS. By analyzing the communication needs of the WAPS, the authors divide messages need to be transmitted into several sorts, and determine the demands of various messages for communication system. Based on that, the optical fiber is selected as the communication medium, and the broadband integrated service digital network based on SDH/SONET and ATM is selected as the network type. A network topology of mixed ring-star is designed. The network makes full use of the IEC 61850 based LAN in substation and power plant. Then, the protocol sets for the key message transmissions are determined. Finally, the transmissions of key messages are simulated using OPNET modeler. The simulation result satisfies the real-time and reliability demands even under the worst situation, which confirms the effectiveness of the communication system.