FDR21 numerical relay offer 3 phase non-directional Over Current and Earth Fault protection for LV and MV power distribution systems. FDR21 is a numerical relay which is suitable for applications such as providing selective protection for overhead and underground feeders (up to 66 kV), AC machines, back up protection for transformers etc. With a microcontroller-based draw-out design and an intelligent Algorithm, numrAL FDR21 offers comprehensive Feeder Protection and Monitoring with Fundamental and True RMS measurement.