Practical Implementation of Multithreaded Communication Protocols in Modern Protection Relays

Microprocessor-based protection relays that provide reliable and fast responses to abnormal conditions are of paramount importance to electrical grids. Modern numerical relays constitute communication protocols to facilitate data exchange among protection devices. Though it has become an integral part of electrical substation devices, there has not been any significant article that puts forth a detailed description of the preemptive multithreading implementation of multiple communication protocols for protection relays. Hence, this article is aimed at designing a preemptive multithreading system comprising IEC 61850 Manufacturing Message Specification (MMS), Generic Object-Oriented Substation Event (GOOSE), and Sampled Values (SV) along with Modbus TCP/IP and IEC 60870-5-104 communication protocols for protection relays. Latest products from prominent manufacturers of protection relays adopt preemptive multithreading on a real-time Linux operating system. In this work, the designed multi-protocol communication system is implemented on a real-time embedded Linux-based cortex-A7 core of the STM32MP157D-DK1 device. The designed system is verified by conducting an interoperability test with ABB REF615 and Thytronic NA11 protection relays.