Vacuum interrupter for a circuit breaker arrangement

Abstract

An exemplary vacuum interrupter for a circuit breaker arrangement including a cylindrically shaped insulating part, within which a pair of electrical contact parts are coaxially arranged and surrounded concentrically by the insulating part. The electrical contact parts can be configured to initiate a disconnection arc only between corresponding inner contact elements after starting a disconnection process, and corresponding outer contact elements can be configured to commutate the arc from the inner contact elements to the outer contact elements until the disconnection process is completed, wherein each inner electrical contact element is designed as a TMF-like contact element for generating mainly a transverse magnetic field, and each outer electrical contact element is designed as an AMF-like contact element for generating mainly an axial magnetic field.

Claims

1. A vacuum interrupter for a circuit breaker arrangement comprising: a cylindrically shaped insulating part, within which a pair of electrical contact parts are coaxially arranged and surrounded concentrically by the insulating part, wherein the electrical contact parts include means for initiating a disconnection arc only between corresponding inner electrical contact elements after starting a disconnection process, and corresponding outer electrical contact elements include means for commutating said arc from the inner electrical contact elements to the outer electrical contact elements until the disconnection process is completed, wherein each inner electrical contact element is designed for generating a transverse magnetic field, and each outer electrical contact element is designed for generating an axial magnetic field, wherein each outer electrical contact element includes an electrical coil for generating the axial magnetic field, and each inner electrical contact element has one of a disk, star or spiral shaped form for supporting or generating the transverse magnetic field, wherein for a double-contact system on both corresponding electrical contact parts the inner electrical contact element is immovably arranged in relation to the outer electrical contact element, and one of the electrical contact parts is movable in relation to the other electrical contact part for a switching function; wherein each inner electrical contact element is coaxially arranged within a corresponding outer electrical contact element, which has a pot-shaped or a tube-shaped geometrical form, and an insulation gap is established between each inner and each outer electrical contact elements, wherein each inner electrical contact element and each outer electrical contact element are integrated to form the electrical contact element, wherein each insulation gap is formed only between adjacent lateral edges of each inner and each outer electrical contact elements.

2. The vacuum interrupter according to claim 1, wherein the insulating part includes a cover plate on each front side in order to form a closed vacuum chamber for accommodation the pair of electrical contact parts.

3. The vacuum interrupter according to claim 1, wherein an additional barrel-shaped metal or ceramic shield is coaxially arranged between the insulating part and the pair of electrical contact parts.

4. A medium-voltage circuit breaker comprising: at least one vacuum interrupter including: a cylindrically shaped insulating part, within which a pair of electrical contact parts are coaxially arranged and surrounded concentrically by the insulating part, wherein the electrical contact parts include means for initiating a disconnection arc only between corresponding inner electrical contact elements after starting a disconnection process, and corresponding outer electrical contact elements include means for commutating said arc from the inner electrical contact elements to the outer electrical contact elements until the disconnection process is completed, wherein each inner electrical contact element is designed for generating a transverse magnetic field, and each outer electrical contact element is designed for generating an axial magnetic field, and wherein each outer electrical contact element includes an electrical coil for generating the axial magnetic field, and each inner electrical contact element has one of a disk, star or spiral shaped form for supporting or generating the transverse magnetic field, the at least one vacuum interrupter being configured for at least one pole part operated by an electromagnetic actuator as switch operation means, wherein for a double-contact system on both corresponding electrical contact parts the inner electrical contact element is immovably arranged in relation to the outer electrical contact element, and one of the electrical contact parts is movable in relation to the other electrical contact part for a switching function; wherein each inner electrical contact element is coaxially arranged within a corresponding outer electrical contact element, which has a pot-shaped or a tube-shaped geometrical form, and an insulation gap is established between each inner and each outer electrical contact elements, wherein each inner electrical contact element and each outer electrical contact element are integrated to form the electrical contact element, and wherein the insulation gap is formed only between adjacent lateral edges of each inner and each outer electrical contact elements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The foregoing and other aspects of the disclosure will become apparent following the detailed description of the disclosure when considered in conjunction with the enclosed drawings.

(2) FIG. 1 is a longitudinal section through a medium-voltage circuit breaker having a vacuum interrupter arrangement in accordance with an exemplary embodiment of the present disclosure;

(3) FIG. 2 is a schematic longitudinal section view of a first arrangement of corresponding electrical contact parts in accordance with an exemplary embodiment of the present disclosure;

(4) FIG. 3 is a schematic longitudinal section view to a second arrangement of corresponding electrical contact parts in accordance with an exemplary embodiment of the present disclosure;

(5) FIG. 4 is a schematic front view on the surface of a first electrical contact element arrangement in accordance with an exemplary embodiment of the present disclosure;

(6) FIG. 5 is a schematic front view on the surface of a second electrical contact element arrangement in accordance with an exemplary embodiment of the present disclosure;

(7) FIG. 6 is a longitudinal section view to a double contact system of vacuum interrupter in accordance with an exemplary embodiment of the present disclosure;

(8) FIG. 7 is a longitudinal section view to a single contact system of vacuum interrupter in accordance with an exemplary embodiment of the present disclosure; and

(9) FIG. 8 is a schematic front view on the surface of a third electrical contact element arrangement in accordance with an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

(10) Exemplary embodiments of the present disclosure provide a vacuum interrupter solution for a circuit breaker arrangement with an easy process to manufacture pair of electrical contact parts for a high switching performance.

(11) According to the present disclosure each inner electrical contact element is designed as a TMF (Transverse Magnetic Field) contact element for generating mainly a transverse magnetic field, and each outer electrical contact element is designed as an AMF (Axial Magnetic Field) contact element for generating mainly an axial magnetic field.

(12) The specific combination of these electrical contact elements ensures a high current interruption performance. Moreover, the electrical contact elements according to the present disclosure are relatively easy to manufacture. Furthermore, the special electrical contact element combination provides the electro-physical effect that the heat arising during the arcing phase is widespread on the contact surfaces. Moreover, the life time of a vacuum interrupter including (e.g., comprising) special electrical contact elements according to the present disclosure has a relatively longer life time than known vacuum interrupter since the initial arcing phase and the subsequent arcing phase are decoupled. Due to the lower voltage that can be specified for the arc to sustain on the AMF-like contact element, the arc will always at least partly commutate.

(13) In order to achieve a significant electro-physical effect as described above the outer AMF-contact element of each electrical contact part can include (e.g., comprise) an electrical coil for generating a strong axial magnetic field.

(14) In contrast the inner TMF-like contact element of each electrical contact part can have a disk, butt or pin, spiral- or star-shaped form for at least supporting the transverse magnetic field.

(15) According to an exemplary embodiment of the disclosure the inner electrical contact element of each electrical contact part is coaxially arranged within the corresponding outer electrical contact element, which has a pot-shaped or a tube-shaped geometrical form. Certainly also intermediate forms are possible for that special coaxial arrangement.

(16) Both different electrical contact elements can be attached to a common contact rod as a support element in various ways. According to a first exemplary embodiment, a single contact system is provided. On one electrical contact part, the inner electrical contact element is immovably arranged in relation to the outer electrical contact element and on the other electrical contact part only the inner electrical contact element is moveable arranged in relation to the outer electrical contact element and in relation to the corresponding electrical contact part. Thus, both corresponding outer AMF-like contact elements can be fixed closely adjacent one to another inside the insulating part forming a constant intermediate gap. According to an exemplary embodiment, the inner electrical contact element can be the outer electrical contact element can be separately attached to the distal end of a common contact rod. The contact rod is fixed to the housing of the vacuum interrupter.

(17) According to a second exemplary embodiment a double-contact system is realized in that on both corresponding electrical contact parts the inner electrical contact element is immovably arranged in relation to the outer electrical contact element. At least one of both electrical contact parts is moveable mounted in relation to the surrounding insulating part in order to form an electrical switch operated by manual or automatic switch operation means, as such an electro-magnetic actuator.

(18) In order to form a closed vacuum chamber for accommodating the pair of electrical contact parts, the insulating part can include a cover plate on each front side. Both cover plates also serve as a mechanical support for contact rods as mentioned above.

(19) Furthermore, an additional barrel-shaped metal or ceramic shield can be arranged coaxially between the insulating part and the inner pair of electrical contact parts. That shield avoids a formation of a metallic layer on the inside of the inner wall of the insulating part in connection with the special electrical contact pieces according to the present disclosure.

(20) FIG. 1 is a longitudinal section through a medium-voltage circuit breaker having a vacuum interrupter arrangement in accordance with an exemplary embodiment of the present disclosure. The medium voltage circuit breaker as shown in FIG. 1 principally consists of an insulating part 1 of a vacuum interrupter within which a pair of electrical contact parts 2a, 2b is coaxially arranged. An immovable (e.g., stationary) electrical contact part 2a corresponds with a moveable electrical contact part 2b. Both electrical contact parts 2a and 2b have corresponding outer electrical connectors 3a and 3b respectively and they form an electrical switch for electrical power interruption inside a vacuum chamber 4 of the insulating part 1.

(21) The moveable electrical contact 2b is moveable between the closed and the opened position via a jackshaft 5. The jackshaft 5 internally couples the mechanical energy of an electromagnetic actuator 6 to the moving electrical contact 2b inside the insulating part 1. In order to ensure an electrical connection between the moveable electrical contact part 2b which is moveable attached to the electro-magnetic actuator 6 a flexible connector 7 is provided between said moveable electrical contact part 2b and the outer electrical connector 3b.

(22) According to an exemplary embodiment disclosed herein, each electrical contact part 2a and 2b consists of two different kinds of contact elements. An inner electrical contact element 8a; 8b is designed as a TMF-like contact element and each corresponding outer electrical contact element 9a; 9b is designed as an AMF-like contact element.

(23) FIG. 2 is a schematic longitudinal section view of a first arrangement of corresponding electrical contact parts in accordance with an exemplary embodiment of the present disclosure. According to FIG. 2, a double-contact system is realized. On both corresponding electrical contact parts 2a and 2b the inner electrical contact element 8a and 8b respectively is immovably arranged in relation to the outer electrical contact element 9a and 9b respectively. Each inner electrical contact element 8a, 8b can be coaxially arranged within the corresponding outer electrical contact element 9a, 9b. The outer electrical contact element 9a, 9b has a pot-shaped geometrical form in order to accommodate the respective inner electrical contact elements 8a and 8b ensuring an insulation gap between the inner and the outer electrical contact elements 8a and 9a or 8b and 9b.

(24) FIG. 3 is a schematic longitudinal section view to a second arrangement of corresponding electrical contact parts in accordance with an exemplary embodiment of the present disclosure. According to FIG. 3, a single contact system is provided, wherein on one electrical contact part 2a the inner electrical contact element 8a is immovably arranged in relation to the corresponding outer electrical contact element 9a. In contrast, on the other electrical contact part 2b only the inner electrical contact element 8b is moveable arranged in relation to the outer electrical contact element 9b and in relation to the corresponding electrical contact part 2b. Both corresponding outer AMF-like contact elements 9a and 9b are fixed closely adjacent one to another inside thenot showninsulating part forming a constant intermediate gap 10 which is independent of the switching position of the vacuum interrupter.

(25) FIG. 4 is a schematic front view on the surface of a first electrical contact element arrangement in accordance with an exemplary embodiment of the present disclosure. As shown in FIG. 4, an electrical contact part 2 has an inner electrical contact element 8 with a spiral-shaped form in a TMF-like geometry for providing the transverse magnetic field. The corresponding outer electrical contact element 9 is ring-shaped in order to provide an axial magnetic field.

(26) FIG. 5 is a schematic front view on the surface of a second electrical contact element arrangement in accordance with an exemplary embodiment of the present disclosure. As shown in FIG. 5, an electrical contact part 2 has an inner TMF-like contact element 8 with a plane-shaped form, or disk-shaped form, which corresponds to an outer AMF-like electrical contact element 9 which is identical to the foregoing described embodiment. Alternatively, as shown in FIG. 8, the electrical contact part 2 may have an inner electrical contact element 8 with a star-shaped form. The corresponding outer electrical contact element 9 may be identical to the foregoing described embodiments.

(27) FIG. 6 is a longitudinal section view to a double contact system of vacuum interrupter in accordance with an exemplary embodiment of the present disclosure. As shown in FIG. 6 the cylindrically-shaped insulating part 1 of the vacuum interrupter comprises cover plates 11a and 11b which are arranged on both front sides of the insulating part 1 in order to form a closed vacuum chamber 4. Inside the vacuum chamber 4 a pair of electrical contact parts 2a and 2b is arranged. The first electrical contact part 2a is fixed in relation to the insulating part 1. The corresponding electrical contact part 2b is moveably arranged in relation to the insulating part 1 in order to form an electrical switch. For moving the electrical contact part 2b the corresponding contact rod 13 is operated by anot shownelectromagnetic actuator. Furthermore, a barrel-shaped metal shield 12 can be coaxially arranged inside the vacuum chamber 4.

(28) A double contact system is provided which consists of inner electrical contact elements 8a and 8b respectively which are immovably arranged in relation to corresponding outer electrical contact elements 9a and 9b, respectively. The outer electrical contact elements 9a and 9b have a pot-shaped geometrical form in order to accommodate the corresponding inner electrical contact elements 8a and 8b respectively in an insulated manner.

(29) FIG. 7 is a longitudinal section view to a single contact system of vacuum interrupter in accordance with an exemplary embodiment of the present disclosure. As shown in FIG. 7, a single contact system is illustrated, in which the upper electrical contact part 2a is immovably mounted in relation to the insulating part 1. In contrast, on the other electrical contact part 2b only the inner electrical contact element 8b is moveably arranged in relation to its corresponding outer electrical contact element 9b. Thus, for electrically switching, only the inner electrical contact element 8b moves axially. Between the corresponding outer electrical contact elements 9a and 9b a constant intermediate gap 10 is provided.

(30) When the inner electrical contact elements 8a, 8b are in closed position, the load current flows through them with low contact resistance. For current interruption, the initial arc is generated between the inner TMF-like contact elements 8a, 8b and develops shortly in transition modes as in standard spiral TMF-like contact elements depending on the current level. At low current the arc column expands in diffuse mode with increasing the gap distance and the instantaneous current as well. At high current, the generated transverse magnetic field by the spirals makes the constricted arc rotating shortly between the inner contacts elements 8a, 8b. The arc should reach the inter-electrode gap between inner and outer contacts after a short time of a few milliseconds, and then supposed to commutate entirely to the outer AMF-like contact elements 9a and 9b and remains in diffuse mode until the arc extinction. This idea is supported by the fact that the arc voltage drop through AMF-like contact elements 9a and 9b is distinctly smaller than through TMF-like contact elements 8a and 8b.

(31) Thus, it will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.

REFERENCE LIST

(32) 1 insulating part 2 electrical contact part 3 electrical connector 4 vacuum chamber 5 jackshaft 6 electromagnetic actuator 7 flexible connector 8 inner contact element 9 outer contact element 10 intermediate gap 11 cover plate 12 shield 13 contact rod