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Substation / Transformer

 

 

Substation / Transformer

Aeroacoustic Remediation

 


The extensive use of transformers in an electrical generation and distribution system, has created noise problems by their necessary location.  From a noise view-point the ideal electrical substation would be sited far away from populated areas. This unfortunately is not always possible because of the scarcity of suitable land and other economic design considerations. Also the problem is likely to increase rather than decrease because of the modern tendency to build much larger transformer units to overcome some of the economic problems. It follows, therefore, one of the many aspects a designer must consider is the problem of noise. 

A method often employed on substation sites is to build a screen wall around the transformer, the usefulness of the wall being mainly dependent upon its height and mass, only small attenuations can be obtained from such a relatively expensive treatment, and this is particularly true when comparing noise levels some distance away from the screen wall.  Much more effective than the screen wall is total enclosure in which the noise energy can be contained. Enclosures introduce problems in maintaining adequate electrical clearances for high system voltages. 

When designing a noise enclosure there are five essential points to observe, (1) that the material of the enclosure is suitable for noise reduction; (2) that the transformer is not acoustically coupled to the enclosure; (3) that the space between the transformer tank and the enclosure does not coincide with half the wavelength of the highest frequency involved; (4) that all openings in the enclosure are sealed or fitted with attenuators; and (5) that all transformer connections are made as flexible as possible.  The main concern with the total enclosure method is to ensure that adequate cooling air is provided at the transformer radiators and tank surface.  For larger transformers more cooling air is needed, and this can sometimes be obtained by drawing cooling air into and out of the enclosure by means of fans.  A method of overcoming the large aperture problem, as well as the fan noise, is to use tuned silencers. 

A menu of transformer aeroacoustic remediation protocols, acoustic performance predictions and budgetary cost estimates are depicted on the following page.

 

 

SUBSTATION / TRANSFORMER
ACOUSTIC ENCLOSURES

20 dBA (18 to 22):

*COMPLETE ENCLOSURE - FOUR (4) WALLS & ROOF
*SEPARATE FOUNDATION
*TRANSFORMER ON VIBRATION ISOLATORS
*24" MINIMUM SPACING TO INNER SURFACE
*$32 / SQ. FT. - UTILITY QUALITY
*$24 / SQ. FT. - INDUSTRIAL QUALITY

 

15 dBA (13 TO 17):

*COMPLETE ENCLOSURE BUT LIGHTER CONSTRUCTION
*SAME FOUNDATION
*REDUCED VIBRATION ISOLATION REQUIREMENTS
*24" MINIMUM SPACING TO INNER SURFACE
*$28 / SQ. FT. - UTILITY QUALITY
*$20 / SQ. FT. - INDUSTRIAL QUALITY

 

10 dBA (8 TO 13):

*WALLS ONLY BUT SEALED TO TANK TOP
*SAME PANEL CONSTRUCTION AS 15 dBA ENCLOSURE
*ALTERNATELY, TOTAL ENCLOSURE BUT LIGHTER
*8" TO 24" SPACING TO INNER SURFACE
*$20 TO $24 / SQ. FT. BUT SMALLER PERIMETER
THAN 15 dBA ENCLOSURE

 

6 dBA (5 TO 8):

*PANELS SUPPORTED FROM TANK ON ISOLATORS
*8" MINIMUM SPACING TO INNER SURFACE
*$20 / SQ. FT. BUT SMALLER PERIMETER THAN
10 dBA ENCLOSURE

 

3 dBA (0 TO 3): *CLOSE FITTING PANELS BETWEEN RIBS ON
TRANSFORMER TANK
*$15 / SQ. FT. OF PANEL BUT ABOUT SAME
PERIMETER DIMENSIONS OF TRANSFORMER

THE ABOVE ACOUSTICAL PERFORMACE IS SUBJECT TO SITE INSPECTION BY AN AEC ENGINEER PRIOR TO QUOTATION. CONTACT AEC FOR CURRENT PRICING AND DELIVERY LEADTIME.

 

THE ABOVE QUOTED PRICE ESTIMATES ARE BASED ON 1986 US DOLLARS

 

Download the PDF Datasheet Below by Clicking on Link
 

 

Copyright 2010 Aeroacoustic Engineering Consultants, LLC
Last modified: March 03, 2011