Experimental results from short-circuit faults on a distribution transformer

In an effort to characterize the behavior of the terminal values (primary and secondary voltages and currents) of a distribution transformer during internal short circuit and incipient faults, experiments were performed on a custom-built transformer. This single phase 25 kVA, 7200 V/240 V/120 V two winding transformer included twelve taps distributed on turns along the primary winding and similarly 12 taps distributed along the secondary winding for the purpose of staging faults that involved short circuits of sections of winding turns. The experiments were performed at the downed conductor testing facility at Texas A&M University (USA) over a 19 month period. This paper describes the experimental setup and presents and discusses the results obtained during the experiments.