GB2081020A

GB2081020A - Puffer type compressed gas circuit interrupter

Info

Publication number: GB2081020A
Application number: GB8120795A
Authority: GB
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1980-07-23
Filing date: 1981-07-06
Publication date: 1982-02-10
Also published as: JPS5731746U

Abstract

A puffer-type compressed gas circuit interrupter provided with a stationary venting contact structure 3 utilizing a venting screen 16 within the stationary contact structure and cooperating with a movable venting contact structure 4 mounted on a movable piston 9. A tubular cylindrical insulating housing 2 supports the stationary contact structure and the movable contact structure is disposed within said housing so that the movable piston 9 is movable with respect to the insulating housing to compress a gas within said housing. A movable insulating nozzle 6 mounted on the movable venting contact structure 4 directs gas into the arc. <IMAGE>

Description

SPECIFICATION Puffer type compressed gas circuit interrupter The present invention relates to puffer type compressed gas circuit interrupters using a single pressure utilized within the interrupting structure.

The relative motion between the operating cylinder assembly and the piston structure achieves a desirable compression of gas therebetween within a compression chamber which compressed gas is utilized during arc interruption by forcing said compressed gas through a nozzle structure to direct the high pressure gas flow intimately into engagement with the established arc drawn within the nozzle to affect the latter extension.

Circuit interrupters are known from the specification of U.S. Patent Nos. 2,429,311,and 3,786,215. Additional patent specification of interest with piston structures are U.S. Patent Nos.

4,139,753 abd 3,588,407.

According to the present invention, a gas circuit interrupter comprises a pair of separable contact means operable between opened and closed positions being disposed within an insulating housing, a piston structure disposed within said insulating housing movable with respect to each other to compress a gas within said insulating housing, operating means for moving the separable contact means between the opened and closed operating positions, flow means for directing a gas which is compressed between said insulating housing and piston structure into engagement with an arc drawn between said separable contacts to effect extinction of said arc during an opening operation and a venting screen disposed to vent hot gases and arcing products away from the separated contacts.

Conveniently, this puffer type compressed gas circuit interrupter has particular application in the 34.5 kV to 72.5 kV voltage rating having stationary vented contact structure utilizing a venting screen within said contact structure and cooperable with a movable venting contact structure mounted on a movable piston structure.

A tubular cylindrical insulating housing supports the relatively stationary hollow venting contact structure and the relatively movable cooperable venting contact structure is disposed within the tubular cylindrical insulating housing such that the movable piston structure is movable with respect to the tubular cylindrical insulating housing to compress a gas within said tubular cylindrical insulating housing. The efficiency of the new puffer type compressed gas circuit interrupter is improved by utilizing a hollow insulating movable nozzle connected to the movable cooperable venting contact structure with a diverging angle that directs the gas being compressed into engagement with the arc drawn between the cooperable relatively stationary and movable contact structures.A further advantage of the present invention is accomplished by adding antistress plug-in means for connecting the entrance bushings for the incoming and outgoing power lines.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a vertical sectional view taken through one embodiment, illustrating a double flow puffer type circuit interrupter with separable contacts being illustrated in the closed position; Fig. 2 is a view similar to that of Fig. 1, but illustrating the disposition of several parts in the fully opened position; Fig. 3 is a sectional view of the stationary contact structure; Fig. 4B is a sectional view of the stationary arcing contact structure; Fig. 4A is a sectional view taken generally along the lines lVB-lVB; and Fig. 5 is a sectional view of the movable contact structure.

Figs. 1-2 illustrate puffer-type compressed gas circuit interrupter 1 having an insulating housing 2, with a stationary contact assembly 3 and a contact assembly 4 contained within the housing 2. The housing 2 is comprised of a filament wound glass epoxy material. Two sets of transfer contacts 8 are provided to make a plug-in connection with the bushing conductors for the incoming and out-going power lines. This plug-in connection allows any movement between the interrupter and the bushings due to thermal expansion or operations to be compensated for in the transfer contacts 8 instead of imposing additional stress on the bushing assembly or the interrupter assembly.In the closed position current is transferred from the bushing conductor entering on one side of the housing 2 through transfer contacts 8 to a pair of finger contacts 5 that make a connection with the movable contact assembly 4, from the movable contact assembly 4 to the stationary contact assembly 3, and exits the interrupter assembly through a second set of transfer contacts 8 at the top of the housing 2.

Referring now to Figs. 3 and 4 the stationary contact assembly 3 is generally comprised of a stationary contact base 1 8 with fourteen equally spaced stationary contact fingers 10 mounted to the base by means of screws 30. A copper venting screen 1 6 is placed within the stationary contact fingers 10 between the base 1 8 and a stationary arcing contact 12. The arcing contact 12 is mounted to the stationary contact fingers 10 by means of mounting screws 31. The arcing contact 12 has a center opening 24 and (14) vent openings 25 in its base.During interruption, hot gases are exhausted upstream through the center opening 24 and venting openings 25 to the copper venting screen 1 6. These vent openings 24, 25, along with the venting screen 1 6 cooperate with vent openings 1 7 and 1 9 in the stationary contact base 1 8 for upstream exhaust.

Fig. 5 illustrates the movable contact assembly 4. The movable contact assembly 4 is generally comprised of a movable hollow tube structure 40 upon which is connected a piston structure 9. The piston structure 9 includes arcing contacts 11 that make contact with the stationary arcing contacts 12 and arc blast openings 13 that are blocked closed when the two arcing contacts 11 and 1 2 are making contact and open when these arcing contacts part during interruptions. Mounted upon the piston structure 9 is a Teflon orifice 6 having a diverging angle between 8--120 that directs the arc blasts from openings 13 into the arc established between the arcing contacts 11 and 12 during the opening operations.It has been discovered by experimentation that a diverging angle of 100 provides optimum performance under high current conditions. The lower portion of the movable contact assembly 4 includes vent openings 7 in the hollow tube structure 40 and openings 41, 42, and 43 for connecting an operating rod 22 by means of a pin 23.

During the opening operation the operating rod 22 is operable to move the movable contact assembly 4 in a downward direction. On opening, the piston structure 9 separates from the stationary contact fingers 10 and compresses the gas 20 within the region 15, initially thereafter contact is only maintained between the stationary arcing contact 12 and the movable arcing contact 11. Downward continuing motion of the operating rod 22 continues to force the piston structure 9 downwardly within the housing 2 compressing gas 20 in the region 1 5. Upon separation of the arcing contacts 11 and 12 arc blast openings 13 are unblocked and the gas 20 is forced through the arc blast openings 1 3 upwardly through the orifice 6 into the arc 14 established between the arcing contacts 11 and 12 as illustrated in Figure 2. Hot gases and arcing products are swept upstream away from the interrupting region through the center opening 24 and the vent openings 25 of the stationary arcing contact 12.

This upstream exhaust is important to establish long arc time, maximum current interrupting conditions where the maximum gas flow is required to reduce the plasma temperature for efficient interruption. On opening hot gases are also vented downstream through the center of the movable hollow tube structure 40 and out the vent openings 7. These gases are cooled by means of a copper venting screen 44 contained within a copper shielding 45. Thus this double-flow exhaust greatly improves the interrupting capability of the puffer-type interrupter described herein by maintaining a high dielectric strength in the interrupting region after opening.

Claims

1. A compressed gas circuit interrupter comprising a pair of separable contact means operable between opened and closed positions being disposed within an insulating housing, a piston structure disposed within said insulating housing movable with respect to each other to compress a gas within said insulating housing, operating means for moving the separable contact means between the opened and closed operating positions, flow means for directing a gas which is compressed between said insulating housing and piston structure into engagement with an arc drawn between said separable contacts to effect extinction of said arc during an opening operation and a venting screen disposed to vent hot gases and arcing products away from the separated contacts.

2. A circuit interrupter as claimed in claim 1, including anti-stress plug-in means for connecting bushings for incoming and outgoing power lines.

3. A circuit interrupter as claimed in claim 1 or 2 wherein said flow means comprises a hollow insulating nozzle having a.divergingangle of 80 to 120 and gas being compressed between said insulating housing and piston structure is disposed to be forced through said hollow insulating nozzle into engagement with an arc drawn between said separable contacts.

4. A circuit interrupter as claimed in claim 3 wherein said flow means comprises a hollow insulating nozzle having a diverging angle of 100 and gas being compressed between said insulating housing and piston structure is disposed to be forced through said hollow insulating nozzle into engagement with an arc drawn between said separable contacts.

5. A circuit interrupter as claimed in any one of claims 1 to 4 in which the stationary contact structure is of hollow form and comprises a stationary hollow contact support base, a stationary hollow arcing contact, a cluster of circumferentially disposed resilient contact fingers encircling said stationary hollow arcing contact, a venting screen disposed within said cluster of circumferentially disposed resilient contact fingers, the movable venting contact structure is of hollow form, comprising a movable tubular venting arcing contact, and a movable piston structure carrying said movable tubular venting arcing contact, a tubular cylindrical insulating housing supporting said stationary hollow venting contact structure and said movable hollow venting contact structure being disposed within said tubular cylindrical insulating housing, said movable piston structure and said tubular cylindrical insulating housing being movable with respect to each other to compress a gas within said tubular cylindrical insulating housing, antd a movable contact operating rod making an engagement with said movable hollow venting contact structure to effect operation of the stationary hollow venting contact structure and the movable hollow venting contact structure.

6. A circuit interrupter as claimed in claim 5 wherein said insulating housing comprises a venting screen.

7. A circuit interrupter as claimed in claim 6 wherein said movable hollow venting contact structure further includes the movable nozzle comprising an 80 to 120 diverging angle, and gas being compressed between the insulating housing and the movable piston structure is disposed to be forced out of the insulating housing through the movable nozzle and into engagement with an arc drawn within the movable nozzle and between said movable tubular venting arcing contact and said cluster of contact fingers during the opening operation.

8. A circuit interrupter as claimed in claim 7 wherein said movable venting contact includes the movable nozzle having a 100 divergence.

9. A circuit interrupter as claimed in any one of claims 1 to 8 wherein said insulating housing is comprised of a glass filament wound epoxy tube.

10. A compressed gas circuit interrupter constructed and adapted for use, substantially as hereinbefore described and illustrated with reference to the accompanying drawings.