Reliability and availability analysis of IEC 61850 based substation communication architectures

To achieve interoperability among multi-vendor substation automation devices, international electro-technical commission (IEC) has published IEC 61850 standard for communication networks within power substations. This standard specifies the communication systems based on Ethernet networks for the substation automation systems (SAS). Ethernet provides flexibility in terms of configuring various architectures with the help of Ethernet switches. However, the reliability and availability of the applicable Ethernet architectures need to be analyzed before they are implemented for critical applications in substations. This paper presents the reliability and availability evaluation of the practical Ethernet switch architectures using reliability block diagram (RBD) approach. The reliability block diagrams have been built for the intra-bay and inter-bay communications considering a typical transmission substation. Further, the reliability and availability of the practical Ethernet architectures have been compared and some suggestions have been made using the final results.