Design and performance improvements in power transformers using ribbon cable

An advanced core-form power transformer with significantly lower losses and weight has been produced and brought to commercial status. First, a number of designs and design studies were made on actual medium power transformer specifications. Several windability models were built, as well as a complete 250 kVA core-form advanced power transformer model to develop the new manufacturing technology and to verify many performance characteristics of the new technology. Then extensive thermal, short-circuit strength, and loss studies were made. Finally, a cooperating electric utility ordered two units, one conventional and one advanced, to the same specification to provide ideal conditions for the verification of the new technology. Construction and test of the prototype proceeded without incident. Full verification was achieved for all aspects of the technology: dielectric design, thermal design, short-circuit strength, loss performance, impedance, noise level, and manufacturability. The prototype was installed and energized in 1991 and continues in operation today. Subsequently, other units were built and tested, with performance results confirming the technology