A classical approach in modelling the air-core transformer

In this paper, a specially designed air-core power transformer, to be employed in a small power tapping scheme from HVDC transmission systems, is studied. First, the transformer is analyzed by classical electromagnetic theory. Next, a small prototype transformer is built and studied in the laboratory. Experimental results, confirm the validity and accuracy of the proposed method for calculating the self- and mutual-inductances of the transformer. The results of the digital simulation of the transformer by the EMTDC/PSCAD software package, are in good agreement with the lab observations.