ABSTRACT
The sound level of a power transformer gets more attention at present since some substations are adjacent to residential areas. Contributions of magneto-motive force, and magnetostriction to no-load sound, are discussed accompanied with an example to show influence of the production qualities such as gap in core and yoke wave to the core sound. An empirical formula based on tested results is presented for the no-load sound estimation. The measures to weaken the sound source and to mitigate sound transmission are valued. Besides no-load sound, detail studies on load sound are conducted with the present trend of test results, as well as the mitigation method. After discussion of the sounds from fans, the calculation of total sound is presented with example. A study shows that low no-load sound doesn’t help to reduce the total sound. Finally, the definitions of sound pressure level, sound power level and sound intensity level and their relations, and the process of test data of sound pressure level to get sound power level are presented.
