Generator, Transformer and Station Bus Relay Replacement

Working at the Cabot hydroelectric generating station, owned by FirstLight Power Resources, TRC completed engineering services to replace the entire plant’s protective relay equipment.

Between October 2018 and June 2019, our electrical engineers replaced the original existing electromechanical protective relays with state-of-the-art Schweitzer Engineering Laboratories (SEL) microprocessor relays.  The relay replacements covered the hydro station’s six generators (including stator ground protection), two station buses, generator step-up transformer and the station service transformer.

We provided all the necessary design drawings to complete the project at the facility and provided protective relay settings and proper relay coordination for all the new relays that were installed, including detailed setting basis documents, relay setting calculations, and relay setting file development.

As a result, the station’s aging electromechanical relays was upgraded with modern digital protection relays, increasing flexibility, security and reliability, while reducing required maintenance activities.