The IEC 61850 standard specifies network redundancy which

improves the system availability for substation communication.

The network redundancy is based on two complementary

protocols defined in the IEC 62439-3 standard: PRP and HSR

protocols. Both the protocols are able to overcome a failure of a

link or switch with a zero switch-over time. In both the

protocols, each network node has two identical Ethernet ports

dedicated for one network connection. The protocols rely on

the duplication of all transmitted information and provide a zero

switch-over time if the links or switches fail, thus fulfilling all the

stringent real-time requirements of substation automation.

In PRP, each network node is attached to two independent

networks operated in parallel, thus providing zero time recovery

and continuous checking of redundancy to avoid failures. The

networks are completely separated to ensure failure

independence, and can have different topologies.