The FREJA? 300 relay testing system is a computer-aided relay testing and simulation system. The weight of FREJA 300 is only 15 kg. The rugged hardware design is built for field use over a wide temperature range, with the possibilities of intelligent software to perform rapid testing. FREJA 300 can be operated with or without a PC. After being put into the Local mode, FREJA 300 can be used stand-alone without a PC. Using the Local mode is easy. The function of each key is described on the display, which also presents the settings and measured values. The very accurate (typically 0.01%) low level analogue inputs are designed for transducer measurements. The high level inputs can be used as a normal volt- and ammeter. FREJA 300 can generate 4×150 V (82 VA) and 3×15 A (87 VA) or 1×45 A (250 VA). Each output can be varied independently. Both static and dynamic testing can be performed, such as prefault and fault generation, simultaneous ramping of several quantities and wave form editing. FREJA 300 can be also be used as a fault simulator to ensure proper relay configuration for specific applications. This is possible by importing and re- generating transient disturbance files often referred to as COMTRADE files. These files may include calculated digital records created by power network simulator software?s such as EMTP, RTDS or data records from actual fault events.