Coordination of Protection Equipment in Synchronous Generator-Based Microgrids with Regard to Maintaining First Swing Stability

With the addition of distributed generation resources to the structure of distribution networks, at the time of the fault, the amount and direction of flow through the main and backup protections changes and disrupts the coordination between them. Synchronous generator-based sources, meanwhile, are more sensitive to error fixing times and their stability may be compromised. Since the troubleshooting time depends on the performance of the protection system, this paper proposes the most suitable protection combination for systems with synchronous generators by examining the types of combinations for protection elements (relay-relay, relay-recloser and recloser-fuse). Slowly On the other hand, this paper presents a solution by which, while maintaining the stability of the first oscillation of synchronous generators in the distribution network, the coordination between the main protection and the backup in the event of an error and in the presence of these sources can be maintained. There is no need to change or redesign the protection system in this solution. The proposed method, by activating the instantaneous characteristic along with the characteristic curve of the relay in the system, was able to establish coordination between the protections and transient stability of the synchronous generators in the distribution system for a penetration coefficient of 0 to 100%. The results of the implementation of the proposed method on the standard 33-bus IEEE test system in the ETAP software environment confirm its capability.