Electrical bushing suitable for attachment between two electrical apparatus enclosures

Claim 2

A bushing assembly for electrically connecting a high-voltage electrical lead contained within a first enclosure to a highvoltage electrical lead contained within a second enclosure, said first and second enclosures having fluid dielectric therein, said bushing assembly comprising first and second casing portions, a center member having a first flange attached to said first enclosure and a second flange attached to said second enclosure, said first and second casing portions being disposed in rigid relationship with said center member, resilient means for forcing said first and second casing portions toward said center member, said first casing portion being located within said first enclosure, said second casing portion being located within said second enclosure, said bushing assembly having means providing two interfaces between the dielectric contained within said first enclosure and the dielectric contained within said second enclosure.

Claim 3

The bushing assembly of claim 1 wherein the first and second casing portions have substantially smooth outer surfaces, the dielectric contained within said first enclosure comprises sulfur hexafluoride gas, and the dielectric contained within said second enclosure comprises mineral oil.

Claim 4

A bushing assembly for electrically connecting a high-voltage electrical lead contained within a first enclosure to a high-voltage electrical lead contained within a second enclosure, said first enclosure containing a first fluid dielectric at a first pressure value, said second enclosure containing a second fluid dielectric at a second pressure value, said first pressure value being greater than said second pressure value, said bushing assembly comprising a center member having first and second ends, said center member having a substantially cylindrical shape with a first flange located at said first end and a second flange located between said first and second ends of said center member, said first flange being sealingly attachable to said first enclosure, said second flange being sealingly attachable to said second enclosure, a substantially cylindrical lead tube having first and second ends, said lead tube being positioned coaxially with said center member, first terminal means attached to said first end of said lead tube, a first casing having a substantially tapered tubular shape, said first casing being coaxially disposed around said lead tube and located between said first terminal means and said first end of said center member, second terminal means attached to said second end of said lead tube, a second casing having a substantially tapered tubular shape, said second casing being coaxially disposed around said lead tube and located between said second terminal means and said second end of said center member, said first terminal means including resilient means for producing compressive forces between said terminal means, said casings, and said center member.

Claim 5

A bushing assembly for electrically connecting a high-voltage electrical lead contained within a first enclosure to a high-voltage electrical lead contained within a second enclosure, said first enclosure containing a first fluid dielectric at a first pressure value, said second enclosure containing a second fluid dielectric at a second pressure value, said first pressure value being greater than said second pressure value, said bushing assembly comprising a center member having first and second ends, said center member having a substantially cylindrical shape with a first flange located at said first end and a second flange located between said first and second ends of said center member, said first flange being sealingly attachable to said first enclosure, said second flange being sealingly attachable to said second enclosure, a substantially cylindrical lead tube having first and second ends, said lead tube being positioned coaxially with said center member, first terminal means attached to said first end of said lead tube, a first casing having a substantially tapered tubular shape, said first casing being coaxially disposed around said lead tube and located between said first terminal means and said first end of said center member, second terminal means attached to said second end of said lead tube, a second casing having a substantially tapered tubular shape, said second casing being coaxially disposed around said lead tube and located between said second terminal means and said second end of said center member, said first terminal means including resilient means for producing compressive forces between said terminal means, said casings, and said center member.

Claim 6

A bushing assembly for electrically connecting a high-voltage electrical lead contained within a bus duct to a high-voltage electrical lead contained within a power transfoRmer, said bus duct containing sulfur hexafluoride gas, said power transformer containing oil, the pressure of said sulfur hexafluoride gas being greater than the pressure of said oil, said bushing assembly comprising a metallic center member having first and second ends, said center member having a substantially cylindrical shape with a first flange located at said first end and a second flange located between said first and second ends of said center member, said first flange being adapted to sealingly attach to said bus duct, said second flange being adapted to sealingly attach to said power transformer, a substantially cylindrical lead tube having first and second ends, said lead tube being positioned coaxially with said center member, a stress graded insulation structure coaxially disposed around said lead tube, said insulation structure including a plurality of cylindrical condenser elements, tap means connected to one of said condenser elements, first terminal means attached to said first end of said lead tube, a first casing having a substantially tapered tubular shape with a substantially smooth outer surface, said first casing being constructed of an epoxy material and being coaxially disposed around said lead tube and located between said first terminal means and said first end of said center member, second terminal means attached to said second end of said lead tube, a second casing having a substantially tapered tubular shape with a substantially smooth outer surface, said second casing being constructed of an epoxy material and being coaxially disposed around said lead tube and located between said second terminal means and said second end of said center member, current transformer means disposed on said bushing between said second flange and said second end of said center member, said first terminal means including resilient means for producing compressive forces between said terminal means, said casings, and said center member for providing a sealed space within said bushing assembly, said sealed space containing oil.

Claim 7

A bushing assembly for electrically connecting a high-voltage electrical lead contained within a bus duct to a high-voltage electrical lead contained within a power transfoRmer, said bus duct containing sulfur hexafluoride gas, said power transformer containing oil, the pressure of said sulfur hexafluoride gas being greater than the pressure of said oil, said bushing assembly comprising a metallic center member having first and second ends, said center member having a substantially cylindrical shape with a first flange located at said first end and a second flange located between said first and second ends of said center member, said first flange being adapted to sealingly attach to said bus duct, said second flange being adapted to sealingly attach to said power transformer, a substantially cylindrical lead tube having first and second ends, said lead tube being positioned coaxially with said center member, a stress graded insulation structure coaxially disposed around said lead tube, said insulation structure including a plurality of cylindrical condenser elements, tap means connected to one of said condenser elements, first terminal means attached to said first end of said lead tube, a first casing having a substantially tapered tubular shape with a substantially smooth outer surface, said first casing being constructed of an epoxy material and being coaxially disposed around said lead tube and located between said first terminal means and said first end of said center member, second terminal means attached to said second end of said lead tube, a second casing having a substantially tapered tubular shape with a substantially smooth outer surface, said second casing being constructed of an epoxy material and being coaxially disposed around said lead tube and located between said second terminal means and said second end of said center member, current transformer means disposed on said bushing between said second flange and said second end of said center member, said first terminal means including resilient means for producing compressive forces between said terminal means, said casings, and said center member for providing a sealed space within said bushing assembly, said sealed space containing oil.