US2336316A - High voltage electric circuit breaker - Google Patents

Description

Dec. 7,1943.

H; THOMMEN HIGH VOLTAGE ELECTRIC CIRCUIT BREAKER Filed May 28, 1941 c L n. w G W MN 2 m WM W m 6 2 F. U j e h .o 4 C M U A 9 w m 5 .m c v. w. a 0 m d p .a T p 6 r I J 1/ I, r I ,.Z 0 3 3 1 4 Patented Dec. 7, 1943 HIGH VOLTAGE ELECTRIC CIRCUIT BREAKER Hans Thommen, Baden, Switzerland, assignor to Aktiengesellschaft Brown, Boveri & Cie, Baden,

Switzerland Application May 28, 1941, Serial No. 395,690 In Switzerland June 8, 1940 Claims.

In order to improve the rupturing conditions in circuit breakers having two or more interruption points per pole or phase the voltage distribution over all points of interruption is made as uniform as possible by arranging a reactor or condenser parallel to each point of interruption or by bridging over the points of interruption by means of ohmic resistances. With the usual type of switch chamber for enclosing the points of interruption, the forces which occur when the circuit is interrupted produce unfavourable stresses in the insulating parts at the joints between these latter and the metal parts. Furthermore this form of construction occupies a lot of space and is unsuitable for assembling in columns.

According to the present invention these disadvantages are overcome by using press devices having tension elements for the assembly of the switch chamber, this latter consisting of a hollow insulator part and end parts preferably of metal.

This arrangement enables not only a favourable mechanical assembly of the switch chamber to be obtained but also has the advantage that particularly with circuit breakers having multiple interruption, parts of the press devices can be employed for controlling the voltage.

constructional examples of the invention are illustrated diagrammatically in the accompanying drawing in which Fig. 1 shows a longitudinal section through the switch chamber of a multiple break gas blast circuit breaker embodying the principles of the invention; and

Figs. 2, 3 and 4 are fragmentary views in partial section of modified embodiments of the invention.

The switch chamber of the multiple break gas blast circuit breaker as shown in Fig. 1 consists of a number of switch elements each of which contains a point of interruption. Each element consists of a hollow cylindrical insulator part a1, a2, a3, etc, and the metallic end parts 171, be, b3, etc., which close the insulators. These metallic end parts are provided with inlet openings c for the supply of compressed gas to the various points of interruption and with outlet ducts d to enable the gas to escape from the arcing contacts. The insulator and metallic parts of the chambers are held together by means of press devices consisting of tension elements e1, er and the connecting compression element 1. Pressure is exerted by means of a press bolt g so that the tension. elements e1, e2 are subjected to a tensile stress.

This manner of assembling the switch chamber can be applied equally well when there are several switch elements each with a point of interruption and arranged one above the other to form a column, or when there is only a single switch element. The switch elements can have several points of interruption if necessary. The number of tension elements used for the press device is quite optional. It is also possible to use a single, preferably tubular, tension element which surrounds the switch chamber or is located inside this latter. When the circuit breaker is of the multiple break type it is an advantage to construct the tension elements so that they can serve at the same time to produce a uniform voltage distribution over the various points of interruption. For this purpose the tension elements can contain resistances as shown in Fig. 1, or capacities h, as shown in Fig. 2, which are connected together in series and bridge-over the points of interruption.

The tension elements e1, 62 can be insulator tubes containing means for producing a uniform voltage distribution, these tubes being provided with petticoats of a suitable form as shown at n, Fig. 3. The insulator tubes can be built with conductive layers, similar to those employed in condenser bushings, so that the tubes themselves act as condensers. The capacity can then be subdivided into several stages connected in series and arranged in parallel with the switch elements. Condenser elements can also be arranged inside the insulator tubes or on the outside of same in layers. A further possibility is to provide the insulator tension elements with an external layer of semi-conductive material 0, Fig. 3, or to construct the tension elements themselves of such a material as shown at 10, Fig. 4. In such a case it is expedient to provide the tension elements with a protective tube q preferably of ceramic material, which has petticoats 1 arranged on it. It is also possible to arrange pieces of semi-conductive material in layers inside the insulator tubes. If resistances are used for controlling the voltage distribution, it is possible to use for this purpose resistances whose eifective ohmic value varies with the impressed voltage, these resistances having a characteristic whereby the current value increases more than proportionally with the voltage, as is for instance the case with carborundum resistances. The capacities or resistances for bridging over the arcing points can be of unequal size and arranged in such a manner that their control effeet is approximately equally favourable when 1. A multiple break gas blast circuit breaker of the type including a plurality of axially alined and superposed arc extinguishing chambers,

2,336,316 j l 1 V extending along and spaced from said chambers,

and means connecting the outer ends of said tension members and including an element adjustable to compress said assembly of hollow insulators and metal plates.

3. A multiple break gas blast circuit breaker as recited in claim 1, wherein said retaining means comprises a plurality of tension members extending along and spaced from said chambers, and means connecting the outer ends of said .,t,ension members and including an element adjustable to compress said assembly of hollow insulators and metal plates; said tension members each chamber comprising a hollow cylindrical insulator and metal plates extending across the ends thereof to form the top and bottom walls of the chamber, a pair of cooperating contacts within each chamber and separable upon the introduction of a pressure gas into the chamber, one contact of each pair being of nozzle form and opening into an exhaust blast passage extending transversely through the adjacent metal plate wall of the chamber to atmosphere, the metal plate walls having axial openings for the passage of pressure gas from chamber to chamber, means retaining said chambers in assembled relation, and impedance means establishing a predetermined voltage gradient along the several pairs of contacts upon the opening of the circuit breaker, characterized by the fact that said retaining means includes a tension member and means cooperating therewith for compressing said assembly of cylindrical insulators and metal plates, and that said impedance means is carried by said tension member.

2. A multiple break gas blast circuit breaker as recited in claim 1, wherein said retaining means comprises a plurality of tension members being tubular, and said impedance means being located within said tension members.

4. A multiple break gas blast circuit breaker as recited in, claim 1, wherein said retaining means comprises a plurality of tension members extending along and spaced from said chambers, and means connecting the outer ends of said tension members and including an element adjustable to compress said assembly of hollow insulators and metal plates; said tension members being tubes of insulating material and provided with petticoats.

5. A multiple break gas blast circuit breaker as recited in claim 1, wherein said retaining means comprises a plurality of tension members extending along and spaced from said chambers, and means connecting the outer ends of said tension members and including an element adjustable to compress said assembly of hollow insulators and metal plates; said tension members being of semi-conductive material and constituting said impedance means, in combination with protective insulating tubes enclosing the respective tubular tension members.

HANS THOMMEN.

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