Benchmarking Line Differential Protection under emerging Communication Infrastructures

Transitioning from traditional deployments to next-generation telecommunication technologies enables revolutionising grid automation with virtualised applications operating on the edge.

Wireless technologies also spread the communication networks further into the grid infrastructure, supporting extended deployment of grid applications in areas previously inaccessible due to the high cost of fibre optic connections. For example, advanced 5G technology offers various services, including network slicing and prioritisation, to improve communication reliability for the applications.

This paper presents communication solutions and test setups for line differential protection and compares the impact of the communication infrastructure on the line differential protection performance. Our reference line differential protection solution is a two-end approach communicating between protection relays via a dedicated fibre optic network and proprietary protocol. The edge computing-based solution implements the same differential calculation method, but the communication protocols can be either standard-based routable or non-routable

Sampled Values (SV), and IEC 61850 standard-based routable or non-routable Generic Object

Oriented Substation Event (GOOSE) - both options are presented in the paper. Published SV streams are used at the remote end for differential calculation and GOOSE for application signals. The proposed new solution with routable GOOSE and SV supports packet-switched communication networks and is tested with a fixed communication network deployment and a public 5G Standalone network using the latest 5G services commercially available.

The traditional reference and the proposed new protection solution are tested in a controller hardware-in-the-loop (CHIL) environment. The architectures of the CHIL communication testbed, the network deployments, test methods, performed tests, and quality of service and

CHIL test results will be presented in the paper. In the results, the findings of measurements are compared to the traditional line differential approach. The main purpose of the study is to prove the viability of new technologies and standards for this specific protection application.

According to the results, the proposed novel implementations are comparable to the traditional implementation without significant differences when using a fixed connection.