The portable STM2 is an universal protection relay test system for all test applications regarding protection relays. Intuitive shortcut-keys makes the operation comfortable and simple. Due to the weight of only 13.6 kg the comfortable protection relay test system is optimal for the areas of system setup and service, as well as calibrator. Due to the modular concept, consisting of 4 modules (Control panel unit, control unit, amplifier, power supply), it is possible to reassemble the STM2 in less than 15 minutes completely. Six current and four voltage outputs with very high output power allow for three-phase test of electro-mechanical relays as well as differential protection relays. The included software makes manual testing comfortable. Test modules and test plans can be run coordinated.