Protection redundancy in a digital network within a high voltage utility substation based on IEC 62439-3

Zero recovery time is an important feature in a protection scheme during a fault scenario. For a protection to maintain its resilience, it is expected that a failure of a link or switch should not jeopardise the overall protection. Development in the protection scheme highlighting the issues based on two complementary protocols i.e., Parallel Redundancy Protocol (PRP) and High-availability Seamless Redundancy (HSR). These two topologies could mitigate the issue of redundancy to a large extent by -building this feature within the protection scheme. It overcomes a link or a switch or a node failure during a zero switchover or delay time. Further, issues arising due to single port failure and interoperability issues related to multi-vendor equipment could be addressed better in IEC 62439-2 published in 2010 taking into account all the shortcomings of Ethernet network failures of a digital protection scheme. In the protection scheme, the Intelligent Electronic Devices (IEDs) with Doubly Attached Node (DAN) components provide redundancy in protection with two active frames in the ring. PRP and HSR topologies not only provide means of redundancies in the protection scheme and communication network but also facilitate standardization of the Ethernet protocols that were vendor specific with number of interoperability issues. In this paper, the author compared the performances between PRP and HSR topologies using Optimized Network Engineering Tool (OPNET) modeller. This software based simulation validated the results of these two topologies and recommended its application in a utility operated high voltage substation.