1.2 kV class porcelain bushing withstanding 45 kV standard lighting impulse voltage

摘要

A porcelain bushing for transformers withstanding impulse voltages rated at 45 kV and 1.2/50 &mgr;s without external flashover, having a creepage to arcing distance ratio of 1.05 to 1.24. The bushing includes a body constituted by a flange fitted with a gasket seat groove, a neck having a curvature radius ranging from 5 to 7 mm, and a mouth equipped with a two-level stepped gasket seat and a semicircular groove. A threaded shank for the attachment of the porcelain bushing to the mounting surface and a groove rail extending along the shank's thread is also provided. In a preferred embodiment, the body is coated with glassy enamel in order to protect the porcelain material against contamination by external agents as well as against the adoption of water.