Suppressing Noise for an HTS Amorphous Metal Core Transformer by Using Microperforated Panel Absorber

Noise pollution is an important issue in modern society. This paper is mainly concerned with noise suppressing of amorphous metal alloy core superconducting distribution transformers (AMSDTs). A microperforated sound absorption structure based on the electroacoustical equivalent circuit model was designed and installed in the inner sides of the box circumference. Up to now, there have been few investigations and reports of its application in superconducting transformer. In this paper, single and double microperforated panels (MPPs) were installed in the inner sides of the box circumference when the box was filled with air. To understand the reduction in vibration noise behaviors of AMSDTs installed with MPPs under normal operation, an AMSDT model was used as the test object, and a single MPP, double MPPs, and different backed cavities filled with the air experimentally and compared when rated voltages were applied to the AMSDT model. Tests were also carried out on the AMSDT model with different temperature air cavity and MPPs made with different materials. An attempt was made to find the largest amplitude and its corresponding frequency on the box surface using vibration sensors, which were arranged on the surface of the box. A data-acquisition platform was set up for signal measurement. The results validate the proposition that the MPP absorber effectively reduces the audible noise of the AMSDT, that the performance is improved by partitioning the backed cavity into differently sized sections, and that the performance is affected when the cavities are filled with air and overexcitation currents or voltages are applied to the AMSDT model. The test results are helpful for optimizing the design and reducing the noise of AMSDTs.