Seamless and low-cost redundancy for substation automation systems (high availability seamless redundancy, HSR)

Numerous Industrial Ethernets are standardized in IEC 61158-IEC 61784. Few provide network redundancy and none provides a redundancy method that is independent of the upper layer protocols. To provide protocol-independent redundancy in (substation) automation networks, IEC SC65C working group 15 produced the IEC 62439 standard series that defines redundancy methods in switched Ethernet networks applicable to a variety of industrial networks, with different solutions depending on the real-time behaviour and on the level of redundancy desired. This paper describes IEC 62439-3 Clause 5 (HSR), a redundancy method applicable to hard real time systems, based on full duplication of the transmitted information and flooding of the network, with recognition and removal of duplicates in each node. This method is applied to a ring, but can be extended to more complex topologies, in particular rings of rings. Its first application is in substation automation based on the IEC 61850 standard which references HSR for applications where redundancy is required.