The Parallel Redundancy Protocol over Wide Area Networks

To accomplish the safety-critical mission of transmission and distribution automation, high availability and stability are always required in the industrial communication networks. The IEC 62439 Standard (Industrial communication networks-High availability automation networks) Part 3 defines the Parallel Redundancy Protocol (PRP) and High-availability Seamless Redundancy (HSR) protocols. Both redundancy protocols target the process bus described in IEC61850 9-2 [1] and support only Local Area Networks (LANs). It has become an active research area to extend the redundancy protocols to the Wide Area Network (WAN) communication with existing network infrastructure. This paper offers a novel solution, namely the parallel redundancy protocol over the wide area networks (PRPW), to enable PRP over WANs with no added overheads to the data frame, while retaining full compatibility. Moreover, PRPW also strengthens the cyber security against spoofing attacks by maintaining a comprehensive list of remote communication units.