Short-Circuit Withstand Tests of Metglas 2605SA1-Based Amorphous Distribution Transformers

This paper deals with EDF Research and Development work for ERDF needs in terms of energy efficiency, focused on Amorphous Metal Distribution Transformers (AMDT). Many prototypes built on Metglas 2605SA1, rated 250 to 630 kVA from different manufacturers, were tested under short-circuit conditions according to IEC and ERDF standards. Some of the prototypes exceeded the accepted value of 4% of impedance variation after short-circuit test. Rectangular windings offer poor resistance to short-circuit stresses. Small metal particles, detached from amorphous core, were found at the bottom of the tank. In that case, dielectric strength is not gifted. The results show the active part should be strong enough to support high electrodynamic forces produced during short-circuit test.