The ABB RER133 is a high-performance protection relay designed for reliable and efficient electrical system monitoring. It offers advanced fault detection, ensuring quick response to overcurrent, undercurrent, and phase imbalances. Both the time-overcurrent and instantaneous overcurrent units are directionally controlled. The electromagnets for the types CO-5, CO-6, CO-7, CO-8 and CO-9 units have. Abstract: Information on the concepts of protection of ac transmission lines is presented in this guide. Brand: ABB Model:REF545KB133AAAA Type:Protection Relay Rated Current:Up to 1200 A Voltage Rating:24-250 V. Article No: 0057075 | HS Code: 85364900 | EAN: 4030641570750 | Weight: 0.