Arrester with external isolator
AssigneeCooper Industries, Inc.
InventorsEdward F. Veverka, Gary L. Goedde, Stanley S. Kershaw
Life of this patent
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Abstract
An arrester for an under oil transformer is connected between a primary bushing lead and an insulator/isolator penetrating the wall of a housing which encloses the oil, arrester, and transformer parts. A ground wire outside the housing is removably connected to the isolator which functions as a circuit disconnector. The ground wire is removed to open circuit the arrester so that the transformer may be tested without having to disable any parts in the housing. Responsive to an arrester failure, the ground wire is blown away to give a visual indication of the failure. The blowing away of the ground wire eliminates the need for the arrester to fail in an open circuit condition.
Claims15
A high voltage protection device for an oil filled high voltage apparatus having a sealed housing containing at least an incoming primary wire connected to the high voltage apparatus, said protection device comprising an arrester insulator/isolator penetrating said sealed housing and sealed to said housing at a location of said penetration, an arrester inside said housing and coupled from said arrester insulator/isolator to a point between said primary wire and said high voltage apparatus, and a removable ground wire and said high voltage apparatus, and a removable ground wire outside said housing and extending from said arrester insulator/isolator to a ground point.
A method of testing a transformer in an oil filled housing, comprising the steps of:
- (a) providing an external arrester insulator/isolator penetrating said housing for making an electrical connection through the housing while preventing a leaking of oil from said housing;
- (b) electrically coupling an arrester inside said housing between an interior end of said arrester isolator and a predetermined potential point within said housing;
- (c) removably and electrically coupling an exterior end of said arrester isolator to a ground potential point;
- (d) removing said ground coupling from said exterior end of said arrester isolator;
- (e) testing said transformer by measuring electrical characteristics on transformer connections emerging from said housing;
- and
- (f) reconnecting said ground coupling to said exterior end of said arrester isolator after said testing is completed
An arrester isolator device comprising an insulator bushing for penetrating through a transformer housing, a sealing gasket engaged by said bushing on one side of said wall for making a sealed joint between said bushing and said wall, a compression means on the bushing and on the other side of said wall for holding said gasket in place and sealing said joint, a stud extending through said insulator for coupling electrical connections from the inside to the outside of said housing, means on an exterior end of said stud for removably attaching an arrester isolator thereto whereby said arrester isolator may be removed and replaced without either opening said housing or breaking said seal, means outside said housing for breaking electrical circuits completed through said insulator and arrester isolator, and means for activating said means outside said housing to break said electrical circuit.
A transformer comprising a housing containing a core and coil assembly, a primary bushing for bringing power into said housing, and bushing being electrically coupled to said coil. arrester isolator means extending through said housing, arrester means inside said housing coupled between said arrester isolator means and said electrical coupling between said primary bushing and said coil, and a ground wire outside said housing removably coupled between said arrester isolator and a ground potential point.
Dependencies are inferred from the claim text.