Manufacturer page.

REX640 is an all-in-one protection and control relay use in advanced power distribution and generation applications with unmatched flexibility available during the complete life cycle of the device. The relay has a modular design for both hardware and software, which allows customization and modification flexibility, and adaptation to changing protection requirements. REX640 relays are used in utility, industrial, and transport and infrastructure applications for protection, control, measurement, and super-vision of power distribution systems. REX640 is based on an application package concept, that offer a variety of ready-made application packages to choose from. The available application packages provide feeder protection, power transformer protection, machine protection, shunt capacitor protection, busbar protection, automatic synchronization, Petersen coil control, and Arc protection with supervised sensors throughout the relay life cycle.