Abstract
The article addresses the implementation of projects for new digital substations, as well as upgrading existing substations using digital intelligent electronic devices. The purpose of the scientific article is to implement the GOOSE protocol into the IEC 61850 standard, enabling all substation process equipment to be interconnected with a single information network. These technological advancements significantly influence the process of operating secondary equipment at substations and, at first, may pose certain challenges during its testing. The experimental analysis confirmed that the mechanism of cyclic transmission of GOOSE messages in REF615 and SEPAM T62 devices operates in accordance with the protocol. The repeated transmission mechanism ensures message delivery and enables detection of communication failures after the maximum period of transmission of GOOSE messages.