Profile: Relay Engineering Services Ltd. develops & markets equipment, and solutions for testing power systems protection relays and associated systems. The APTS3 automatic protection test set features digital signal processing based technology, and integrated 0-260Vdc battery simulator & dual-channel storage oscilloscope. APTS three-phase protection relay test set is the flagship multipurpose relay test set. The APTS utilizes the latest digital signal processing based waveform synthesis techniques coupled with advanced low-noise switching amplifier technology. This combination enables the APTS to deliver precision waveforms at the highest output power available in a portable lightweight computerized test set anywhere. The highest burden single & three-phase electromechanical relays, as well as the latest microprocessor based relays can be tested directly and without the need for additional accessories or amplifiers.