Reliability Modeling and Analysis of IEC 61850 Based Substation Protection Systems

This paper proposes a novel reliability modeling and analysis methodology for modern substation protection systems. A typical IEC 61850 based substation protection system is designed and analyzed using this methodology as an example. This system includes cyber components such as Merging Units (MUs), Intelligent Electronic Devices (IEDs), and process bus, as well as physical components such as transformers, circuit breakers, and transmission lines. A general technique for cyber-physical system reliability analysis and the concept of cyber-physical interface matrix are presented. The failure modes of individual components and their impacts on the overall system are modeled and numerically analyzed. The utility of the cyber-physical interface matrix in the reliability analysis of a composite power system is also illustrated. The cyber-physical interface matrix is the critical idea that helps making the analysis tractable. The results of our study provide important and precise information for substation reliability evaluation and pave the way for the reliability analysis of complex and large scale cyber-physical systems.