Evaluation of Process Bus Data Latency with PRP/HSR Enabled Ethernet Switches

Understanding the switching behaviours of Ethernet switches is critically important for analysing the transfer time of time-critical messages, e.g. Sampled Value (SV) and Generic Object Oriented Substation Event (GOOSE) messages in a complex IEC 61850 Ethernet network. Most analytical models and simulation programs estimate the network latency by assuming a symmetrical port speed at ingress and egress ports with fixed switching delays. However, the switching characteristics are product-specific and can vary significantly depending on the types of switching hardware, transferred messages and port speed. This paper evaluates the switching characteristics of PRP/HSR enabled switches by analysing the time required to forward SV, GOOSE and IEEE 1588 messages using various port types and speeds combinations. The obtained switching behaviours provide an insight into the multi-protocol traffic interactions at substation process bus. The results can also be used as a performance reference for power engineers and academic researchers to improve the accuracy of analytical models and simulation platforms.