In a conventional transformer, secondary voltage and power transfer efficiency decrease when the magnetic flux leaks from the magnetic circuit of the transformer and the leakage reactance increases. Magnetic shielding of the magnetic circuit of the transformer with plural bulk high temperature superconductors (HTSs) was evaluated as a method of improving transformer characteristics. In our previous research, transformer characteristics were evaluated with a constant secondary load at each frequency. In this research, appropriate secondary loads were connected for each frequency to evaluate the characteristics in conformity with the actual transformer operation. The frequency characteristics of transformers with and without bulk HTSs shielding were evaluated with a constant magnetic flux density in the magnetic circuit. An increase in the secondary voltage and power transfer efficiency was confirmed for a transformer with bulk HTSs shielding at all frequencies, as dispersion of the magnetic flux was controlled by bulk HTSs shielding. © 2009 Elsevier B.V. All rights reserved.