Combination ground and test switch apparatus for pressurized-gas-insulated high voltage systems

Claim 2

For use in a metal-enclosed pressurized-gas-insulated highvoltage switchgear system, a double-purpose grounding and test switch assembly capable of grounding a high-voltage internal conductor and of permitting a non-grounded electrical connection to the internal conductor for test purposes, said assembly comprising: a grounded conductive housing completely surrounding said internal conductor and having an opening provided therein; a switch housing mechanically and electrically connected to said grounded conductive housing and having an opening at a first end thereof whereby the pressurized interior of the grounded conductive housing communicates with the interior of said switch housing to maintain an equalized gas pressure therebetween; a reciprocating conductive switch blade; guide means mounted within said switch housing for guiding said conductive switch blade to move along a substantially linear path and through the grounded conductive housing opening; the internal conductor including a jaw blade structure; drive means mounted within said switch housing for moving said conductive switch blade from a first position whereby its free end is disengaged from the jaw contact structure to a second position whereby the free end of said conductive switch blade electrically engages the jaw structure; a terminal mounted to the free end of said switch housing remote from the grounded conductive housing and electrically insulated therefrom; flexible conductive cable means positioned within said switch housing and electrically connected between said terminal and the end of said conductive switch blade remote from the jaw structure for permitting free reciprocating movement of said conductive switch blade while maintaining the integrity of a conductive electric path between said terminal and said conductive switch blade; said guide means including means for electrically insulating said conductive switch blade from the grounded conductive housing and said switch housing; said drive means including an actuating shaft having one end thereof extending outwardly from said switch housing to provide for movement of said conductive switch blade from and to a position exterior of said switch housing; said terminal being selectively connected to ground potential or to test equipment.

Claim 3

The device of claim 1 further comprising a conductive strap selectively connectible between said terminal and said switch housing for maintaining said conductive switch blade at the voltage level of said grounded conductive housing.

Claim 4

The device of claim 1 wherein said drive means further comprises a crank arm formed of an insulating material coupled to said operating shaft for pivoting said crank arm about said operating shaft when said shaft is rotated; a clevis assembly coupled to the end of said conductive switch blade remote from the internal conductor; means for coupling the free end of said crank arm to said clevis assembly.

Claim 5

The apparatus of claim 3 wherein said drive means is further comprised of means for providing an airtight seal in the region where said operating shaft protrudes from said switch housing to prevent the escape of the pressurized gas contained therein.

Claim 6

For use in a metal-enclosed pressurized gas-insulated high-voltage switchgear system, a double-purpose ground and test switch assembly capable of grounding a high-voltage internal conductor and of permitting a non-grounded electrical connection to the internal conductor for test purposes in which a grounded conductive housing surrounds the internal conductor and has an opening provided therein; a switch housing mechanically and electrically connected to said grounded conductive housing and having an opening communicating with the opening of the grounded conductive housing whereby the pressurized interior of the grounded conductive housing communicates with the pressurized interior of said switch housing to maintain an equalized gas pressure therebetween; a conductive switch blade; drive means for moving said conductive switch blade from a first position whereby its free end is electrically disengaged from the internal conductor to a second position whereby the free end of said conductive switch blade electrically engages the internal conductor; an electrical terminal mounted on said switch housing and electrically insulated from said switch housing; conductive means positioned within said switch housing and electrically connected between said electrical terminal and said conductive switch blade and permitting free movement of said conductive switch blade while maintaining the integrity of a conductive electric path between said electrical terminal and said conductive switch blade; said conductive switch blade being electrically insulated from said grounded conductive housing and said switch housing; a conductive strap selectively connectible between said electrical terminal and ground potential for maintaining said conductive switch blade at the voltage level of said grounded conductive housing when said conductive strap is electrically connected to both said electrical terminal and ground potential; said conductive strap designed to be removable to disconnect the electrical connection between said electrical terminal and ground potential to thereby permit a non-grounded electrical connection to be made from test equipment to the internal conductor through said electrical terminal and said conductive switch blade without the need to depressurize the switchgear system and without the need to remove either said switch housing or the grounded conductive housing.

Claim 7

For use in a metal-enclosed pressurized gas-insulated high-voltage switchgear system, a double-purpose ground and test switch assembly capable of grounding a high-voltage internal conductor and of permitting a non-grounded electrical connection to the internal conductor for test purposes in which a grounded conductive housing surrounds the internal conductor and has an opening provided therein; a switch housing mechanically and electrically connected to said grounded conductive housing and having an opening communicating with the opening of the grounded conductive housing whereby the pressurized interior of the grounded conductive housing communicates with the pressurized interior of said switch housing to maintain an equalized gas pressure therebetween; a conductive switch blade; drive means for moving said conductive switch blade from a first position whereby its free end is electrically disengaged from the internal conductor to a second position whereby the free end of said conductive switch blade electrically engages the internal conductor; an electrical terminal mounted on said switch housing and electrically insulated from said switch housing; conductive means positioned within said switch housing and electrically connected between said electrical terminal and said conductive switch blade and permitting free movement of said conductive switch blade while maintaining the integrity of a conductive electric path between said electrical terminal and said conductive switch blade; said conductive switch blade being electrically insulated from said grounded conductive housing and said switch housing; a conductive strap selectively connectible between said electrical terminal and ground potential for maintaining said conductive switch blade at the voltage level of said grounded conductive housing when said conductive strap is electrically connected to both said electrical terminal and ground potential; said conductive strap designed to be removable to disconnect the electrical connection between said electrical terminal and ground potential to thereby permit a non-grounded electrical connection to be made from test equipment to the internal conductor through said electrical terminal and said conductive switch blade without the need to depressurize the switchgear system and without the need to remove either said switch housing or the grounded conductive housing.

Claim 8

The device of claim 5 wherein said switch housing and the grounded conductive housing are mechanically and electrically secured to each other so that they are both maintained at the same ground potential.

Claim 9

The device of claim 6 wherein said drive means moves a portion of said conductive switch blade through the opening of said switch housing and the opening of the grounded conductive housing to mechanically and electrically engage the internal conductor.