Starting Current Limitation Method Using HTS for Induction Motors

Abstract

The typical starting current for an asynchronous three-phase electric motor is in the range of five to ten times the rated current. To mitigate problems caused by this high current, various methods to start this type of motor exist. As an alternative method for starting up induction motors, a new starting current limitation method is proposed, which is based on using commercially available high-temperature superconductor tape. A prototype of the superconducting starting current limiter was constructed and tested with a 55-kW industrial induction motor, in a 440-V/60-Hz three-phase power grid. As the total starting time can be longer than the time the superconductor tape can support a high current, a shunt reactor receives the starting current after 80 ms to avoid damage to the tape. Performance evaluations of the superconducting limiter method were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition to limiting the starting current, our method offers reduced current waveform distortion and lower harmonic pollution during startup.