Reliability evaluation of a substation automation system communication network based on IEC 61850

The application of IEC 61850 brings significant changes to the instrumentation, monitoring, communication, control and protection systems used in the substation automation system (SAS). Compared with the conventional substation system, the implementation of IEC 61850 provides more flexibility in SAS architectures, but it also raises concerns about the reliability and performance of the overall system. This paper proposes a methodology to evaluate the reliability of an all-digital substation considering different topologies of both the station and process buses. The proposed reliability evaluation procedure is based on analytical Reliability Block Diagram (RBD) approach and stochastic Monte Carlo simulation method. This reliability analysis, combined with sensitive analysis, would help indicate the most reliable Substation Communication Network (SCN) architecture to realize a specific communication service. It would also help determine the weak points needed to be improved in order to improve the overall reliability of the automation system.