Upgraded Vibration Isolation of Dry-Type Transformer Cores Within an Electrical Unit Substation

Prior experience with attempts to isolate the vibrations of dry-type transformer cores within an electrical unit substation required isolation of the full substation casing to achieve sufficient noise reduction to the occupied space below. A recent experience with four similar unit substations located in a penthouse above future corporate office space included conditions that made complete isolation of the casing exceedingly difficult and costly. In an effort to avoid the substantial complexity and cost of the more comprehensive casing isolation, upgraded isolation of the transformer cores was attempted. The isolation of the cores was thoroughly studied in order to optimize the isolation of the cores within one unit substation as a mockup. An alternate selection of isolation pads for the transformer core of a second unit substation was also installed and compared. Pre and post measurements of the two isolation approaches were performed and demonstrated that the optimized isolation provided markedly greater performance than the alternate. The results of these measurements and a discussion of the previous casing isolation are presented.