What is Bushings in Transformer?

Transformer Bushings

                                                      

Transformer bushing at 11 kV side should be so designed to accommodate two no. 800 sq.mm. aluminium (1C) cable (utility to customize based on actual requirement and rating of transformer) with secondary inter phase clearance. All bushings shall conform to the requirements of the latest revisions of IEC publication 137.  The bushings shall be located so as to provide minimum electrical clearances between phase and ground as per relevant IS/IEC standards.

All bushings shall be porcelain type and shall be furnished complete with terminal connectors of adequate capacity. The porcelain used in bushings shall be homogeneous, nonporous, uniformly glazed to brown color and free blisters, burns and other defects.

Stresses due to expansion and contraction in any part of the bushing shall not lead to deterioration.

Bushings rated 66 kV and above shall be of the oil-filled condenser type with a central tube and draw-in-conductor which shall be connected to the connector housed in the helmet of the bushings.


Liquid/oil-filled bushings shall be equipped with liquid level indicators and means for sampling and draining the liquid. The angle of inclination to vertical shall not exceed 30 deg. Oil in oil-filled bushings shall meet the requirements of the transformer oil standards specified.

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