ABB REU610 | Voltage relay | Voltage protection relay.REU610 is a voltage relay for system voltage protection, measurement and supervision in utility and industrial power systems.Not active product since 2017.REU610 is a member of ABB’s Relion® product family and part of its 610 product series. The series includes protection relays for feeder protection, motor protection and general system voltage supervision. The plug-in design facilitates the commissioning of the switchgear and enables fast and safe insertion and withdrawal of plug-in units.（www.plc-module.com）

REU610 is designed for distribution substation busbar over-voltage and under-voltage protection, feeder and power transformer over-voltage protection, motor under-voltage protection, and capacitor bank protection and supervision. In isolated neutral power systems, it is also used for non-discriminative earth-fault protection, based on residual voltage measurement. REU610 is used for initializing automatic substation busbar changeover and for disconnecting small power units from the public network, that is, islanding.

Application： REU610 is designed for distribution substation busbar overvoltage and undervoltage protection, feeder and power transformer overvoltage protection, motor undervoltage protection, and capacitor bank overvoltage protection and supervision. In isolated neutral power systems, REU610 is also used for non-discriminative earth-fault protection based on residual voltage measurement. Further, the REU610 is used for initializing automatic substation busbar changeover and for disconnecting small power units from the public network, i.e. islanding, during a major network disturbance. REU610 is also suitable for employment in marine and offshore environments.

ABB REF610 Feeder protection：