Determination of ratio characteristics of cascade connected transformers

The actual ratio of output voltage to input voltage of a group of cascade connected transformers increases with increase in load capacitance. In addition, the voltage distribution within a cascade group is frequently non-uniform and usually the final transformer developes the highest voltage. Both the output voltage and the voltage across the final unit can be obtained by multiplying the primary voltage by the appropriate ratios. Calculations and measurements show that these ratios are linear functions of the input admittance which is readily measured by measuring the input voltage and current. This is possible even with intermediate compensating reactors and also with parallel/ cascade arrangements.