The MiCOM Alstom P44T provides fast, highly selective railway catenary distance protection which combines with the directional decision from the proven delta principle. The trip time is typically 0.7 to 1 cycle. P44T can be used for protection of classic or auto transformer fed catenaries in systems with nominal frequencies 50 or 60Hz. Five zones of protection with quadrilateral characteristics allow versatile deployment as the main protection for all AC catenary/feeder systems. With independently settable right and left hand side resistive reaches for each zone the P44T suits routes hosting regenerative braking trains.

P44T provides advanced load blinding which prevents false tripping due to encroachment of heavy loads. P44T has a range of back up functionalities including auto reclose to supplement the main distance function. Additional to protective functions, P44T has measurements, recording, monitoring and supervisory functions. The inclusion of function keys, ancillary supervision and tri-colour LED annunciation saves panel space. Accurate fault location and high resolution disturbance recording assist post-fault analysis by maintenance crews.

http://www.alstom.com/grid/products-and-services/Substation-automation-system/protection-relays/MiCOM-Alstom-P44T/