What is the primary function of a #25 relay?

The primary function of a #25 relay, also known as a synchronizing relay, is to ensure that the frequency, voltage, and phase angle of the system being connected are properly aligned before synchronization occurs. This is crucial to prevent system disturbances or operational issues when integrating different electrical systems or generators. The relay assesses the conditions of the incoming power system and compares them to the existing system parameters. Only when these parameters are synchronized can the connection be safely made without risking damage to equipment or destabilizing the grid.

This functionality emphasizes the importance of appropriate timing and alignment in electrical operations, underscoring the role of the #25 relay in maintaining stability when connecting various components of an electrical network.