Effects of LAN-based Communication Delays on the Dynamic Stability of Power Systems

This paper studies the delays in local area networks (LAN) for future communication applications in protections of power systems. LAN-based networks are a crucial component in modern power plants and substations, and the usage of these networks for the exchange of information among digital relays is gaining popularity and becoming a standard communication solution. These systems can distribute the information needed for operation of relays and control systems based on supported simple models of LAN networks such as carrier sense multiple access with collision detection (CSMA/CD), carrier sense multiple access with arbitration on message priority (CSMA/AMP), frequency division multiple access (FDMA), time division multiple access (TDMA), PROFINET and Switched Ethernet. The Bandwidth and the date rate are among the most important factors in communications that might cause delays in received information which subsequently, can cause errors in the tripping time of digital relays and hence; the stability of power systems. A case study of a power system and LAN-based network emulator were used to model the communication working conditions and how abnormal working conditions can affect the performance of the dynamic stability of the power systems. Simulation results were presented and discussed.