Patent Application
20230420202
The instant application claims priority to European Patent Application No. 22180589.8, filed Jun. 23, 2022, which is incorporated herein in its entirety by reference.
The present disclosure generally relates to a medium voltage or high voltage circuit breaker, and a medium voltage or high voltage switchgear.
Vacuum interrupters are widely known in the industry, in the applications of low-; medium-; high-voltage circuit breakers.
Movement of the moveable contact 4 is achieved through the push rod 7. The fixed contact 3 is both mechanically and electrically connected to the upper terminal 2. The moveable contact 4 is in electrical contact with lower contact 6. Mechanical fixation of the moveable contact 4 needs to allow for linear movement of this contact towards the fixed contact 3. The housing 1 is also used for improving the dielectric withstand of the whole interior assembly with respect to the surrounding electrical potentials. It is usually made of thermoplastic, duroplastic and/or thermoset material, which enables decreasing distances to the next phase(s) or grounded switchgear walls and provides for increasing creepage distances.
The success of these devices in medium voltage (MV) field has led to the desire the extension of their applications towards higher voltage levels as well. Vacuum interrupters designed for higher voltage levels are feasible, but they are expensive, and they are challenging to develop. When a VI is developed for high voltage applications, significant design effort is needed to improve heat dissipation from such a bulky unit. This, together with lower production volumes applicable, become critical factors when deciding whether such VIs can be utilized in new developments. Furthermore, high voltage applications require large distance from fixed to moveable contact in the open state, resulting in a long path the pushrod 7 needs to travel and subsequently in a big actuating mechanism 8 that has to drive the pushrod 7 in such a distance.
In a first aspect, there is provided a medium voltage or high voltage circuit breaker; comprising:
The first terminal is electrically connected to a fixed contact of the first vacuum interrupter. The second terminal is electrically connected to a fixed contact of the second vacuum interrupter. The interconnection part is configured to be in electrical connection with a movable contact 4 of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with a movable contact of the second vacuum interrupter. In the closed state the movable contacts have been moved to be in contact with the respective fixed contacts. The interconnection part is configured to provide a current path between the movable contacts. A first end of a first lever arm of the lever system is coupled to the movable contact of the first vacuum interrupter, and a second end of the first lever arm is coupled to the operating rod. A first end of a second lever arm of the lever system is coupled to the movable contact of the second vacuum interrupter, and a second end of the second lever arm is coupled to the operating rod. A part at the first end of the first lever arm is supported by the interconnection part and can slide linearly within a slot of the interconnection part or a part at the first end of the first lever arm is supported by the interconnection part and can move linearly with respect to a bearing of the interconnection part.
A part at the first end of the second lever arm is supported by the interconnection part and can slide linearly within a slot of the interconnection part or a part at the first end of the second lever arm is supported by the interconnection part and can move linearly with respect to a bearing of the interconnection part. In a transition from an open state to the closed state the actuator is configured to move the operating rod to move the second end of the first lever arm and the second end of the second lever arm such that the part at the first end of the first lever arm and the part at the first end of the second lever arm move simultaneously within their corresponding slots away from one another or with respect to their corresponding bearings away from one another.
It is to be noted that reference to an end of a lever arm does not require this to be right at the actual end but can be towards or near the actual end.
A new medium voltage or high voltage circuit breaker is now described. In the following a medium voltage or high voltage circuit breaker is described with two vacuum interrupters in series with an interconnection part connecting them. The current new development can be utilized with more than two vacuum interrupters in series, with interconnection parts connecting adjacent vacuum interrupters.
In an example, a medium voltage or high voltage circuit breaker comprises a first terminal 2 (also called an upper terminal), a second terminal 6 (also called a lower terminal), a first vacuum interrupter 5, and a second vacuum interrupter 5. The vacuum interrupters here can be identical but need not be identical. The circuit breaker also comprises an interconnection part 9, an actuator 8, an operating rod 11, and a lever system 12. The first terminal is electrically connected to a fixed contact 3 of the first vacuum interrupter, and the second terminal is electrically connected to a fixed contact 3 of the second vacuum interrupter. The interconnection part is configured to be in electrical connection with a movable contact 4 of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with a movable contact 4 of the second vacuum interrupter. The interconnection part is configured to provide a current path between the movable contacts.
Thus, upon activation the movable contacts of both vacuum interrupters are moved towards the respective fixed contacts until in a closed state the movable contacts are in contact with the fixed contacts. There is then a current path from the first terminal to the second terminal via the first vacuum interrupter, the interconnection part, and the second vacuum interrupter. A first end of a first lever arm of the lever system is coupled to the movable contact of the first vacuum interrupter, and a second end of the first lever arm is coupled to the operating rod. A first end of a second lever arm of the lever system is coupled to the movable contact of the second vacuum interrupter, and a second end of the second lever arm is coupled to the operating rod. A part at the first end of the first lever arm is supported by the interconnection part and can slide linearly within a slot of the interconnection part or can move with respect to a bearing integrated into the interconnection part.
A part at the first end of the second lever arm is supported by the interconnection part and can slide linearly within a slot of the interconnection part or can move with respect to a bearing integrated into the interconnection part. This is shown clearly in
Thus, the second vacuum interrupter is connected in series with the first vacuum interrupter, and in a closed state current can flow from the first terminal to the second terminal when movable contacts of both vacuum interrupters are brought into contact with fixed contacts of both vacuum interrupters.
In an example, the first vacuum interrupter is identical to the second vacuum interrupter.
According to an example, the part at the first end of the first lever arm and the part at the first end of the second lever arm move simultaneously within their corresponding slots or with respect to their corresponding bearings away from one another over the same distance.
According to an example, the interconnection part is configured to be in electrical connection with the movable contact of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with the movable contact of the second vacuum interrupter during at least part of the transition from the open state to the closed state.
According to an example, the interconnection part is configured to be in electrical connection with the movable contact of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with the movable contact of the second vacuum interrupter.
As shown in
According to an example, in a transition from the closed state to the open state the actuator is configured to move the operating rod to move the second end of the first lever arm and the second end of the second lever arm such that the part at the first end of the first lever arm and the part at the first end of the second lever arm move simultaneously within their corresponding slots or with respect to their corresponding bearings towards one another.
According to an example, the part at the first end of the first lever arm and the part at the first end of the second lever arm move simultaneously within their corresponding slots or with respect to their corresponding bearings towards one another over the same distance.
Thus, the ends of the lever arms can move within slots as shown in the figures, however the ends can move with respect to or in bearings or similar that are integrated into the interconnection part, which can lead to a reduction in friction with respect to movement in a slot.
According to an example, the interconnection part is configured to be in electrical connection with the movable contact of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with the movable contact of the second vacuum interrupter.
According to an example, the current path between the movable contacts is provided by at least one wall of the interconnection part.
According to an example, one or more of the at least one wall of the interconnection part comprises ribs on the inner side and/or on the outer side.
According to an example, the interconnection part is open on a first side.
According to an example, the interconnection part is open on a second side opposite to the first side.
According to an example, the interconnection part consists of several elements. Thus, the interconnection part can be formed from several parts or elements, mechanically and electrically connected.
According to an example, the circuit breaker further comprises a housing 1 surrounding the first vacuum interrupter, the second vacuum interrupter and at least partly also the interconnection part. This is shown in
According to an example, a mounting between the actuator and the housing comprises at least one support insulator or other insulated mechanical arrangement 10.
This need not specifically be a post insulator, but it can be, but the mounting serves for mechanical support of the VIs and at the same time ensures a correct distance of medium/high voltage parts from earthed structures.
According to an example, the vacuum interrupters connected in series are not of the same or equal design.
According to an example, the lever system and/or housing and/or interconnection parts are not symmetrically designed and/or connected to both vacuum interrupters used.
Such a circuit breaker can be utilized with a medium voltage or high voltage switchgear.
The new medium voltage or high voltage circuit breaker is now described in specific detail, where reference is made to
In comparison to a single vacuum interrupter structure shown in
Depending on a specific actuator 8 and/or pushrod 7 design, the housing may need to be supported by some electrically insulated supporting parts 10, to withstand the mechanical loads originating from the actuator 8 as well as to provide sufficient insulating distance between terminals and grounded parts of the actuator 8 or surrounding parts.
Connection of the operating rod 11 driven by an actuator is translated by the levers of a lever system 12 into the movement of pushrods 7, that are moving the movable contacts 4 of the vacuum interrupters 5. The lever system 12 has identical first and second lever arms that are each attached to the operating rod at one end and at the other end the respective lever arms are couple to the movable contacts 4 via respective push rods 7. It is to be noted that in this embodiment the two VIs are identical and the first and second lever arms are identical, however if the two VIs are not identical, then the first and second lever arms might also differ.
The two identical VIs 5 can both be designed for nearly half rated voltage compared to a single vacuum interrupter design, but with the same short circuit interruption current performance as a single vacuum interrupter deign. Therefore, the advantage of such a structure is, that series combination of two existing vacuum interrupters can be used for a double voltage level, without the necessity to utilize one higher voltage vacuum interrupter, what could require to design a new single vacuum interrupter for a particular rated voltage level.
Another advantage of the double vacuum interrupter structure is that the distance between the fixed and the movable contacts of the vacuum interrupters can be half in each vacuum interrupter, compared to a distance needed in the situation of a single vacuum interrupter concept. Therefore, considering the same actuator design used in both cases, the opening speed for the two vacuum interrupter designs will be much faster because of two gaps will open at the same time with same speed. Furthermore, each pushrod 7 needs to travel half the distance compared to a situation in a single VI concept.
The interconnecting part 9 interconnecting the two vacuum interrupters to be created out of two identical or similar blocks made from metal, that can carry the current flow through both vacuum interrupters arranged in series as well as provide mechanical support to the mechanism operating the push rod. At the same time, such construction enables better heat dissipation through its opening on two sides, see
Thus, the interconnection part 9 consists of two identical halves mated together. Its main functionality is to ensure proper electrical connection of the two vacuum interrupters connected in series as the whole current is flowing through both half parts. The side walls of the interconnection part 9 and its top and bottom structures provides a large surface area in the design of interconnection part 9, which enables very good heat dissipation and can be designed in addition as heat sink with ribs on the inner and/or outer side, or a suitable surface roughness, or pins, or holes for air flow or all of these. Furthermore, two half designs create an opening on the operating rod side as well as on the opposite side and therefore enables good air or gas flow through this connection, further improving the above-mentioned heat dissipation for example energy can be transferred away from the circuit breaker under current load.
As detailed above
As detailed above, the interconnection part 9 can be built from two blocks, which can also be termed half shells. It is to be noted that each separate half shell construction enables easy insertion of parts separately and thus ensures a smooth assembly process during production of the pole.
In order not to excessively limit the interconnection part 9 from heat exchange, small air gap 100 in-between the interconnection part 9 and housing 1 can be arranged, at least in some areas. Furthermore, ribs or pins can be added to provide the well-known effective heat sink properties. To complement
As shown in
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing a claimed invention, from a study of the drawings, the disclosure, and the dependent claims.
In another example, there can be a design of described circuit breaker, consisting of different VI designs connected in series, i.e., the two VIs used are not identical. This might be needed in order to achieve required dielectric and/or short-circuit current performance. They may also result in a need to have asymmetrical lever system and/or housing and/or interconnection part.
In an example, the part at the first end of the first lever arm and the part at the first end of the second lever arm move simultaneously within their corresponding slots or with respect to their corresponding bearings away from one another over the same distance.
In an example, the interconnection part is configured to be in electrical connection with the movable contact of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with the movable contact of the second vacuum interrupter during at least part of the transition from the open state to the closed state.
In an example, the interconnection part is configured to be in electrical connection with the movable contact of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with the movable contact of the second vacuum interrupter during the transition from the open state to the closed state.
In an example, in a transition from the closed state to the open state the actuator is configured to move the operating rod to move the second end of the first lever arm and the second end of the second lever arm such that the part at the first end of the first lever arm and the part at the first end of the second lever arm move simultaneously within their corresponding slots or with respect to their corresponding bearings towards one another.
In an example, the part at the first end of the first lever arm and the part at the first end of the second lever arm move simultaneously within their corresponding slots or with respect to their corresponding bearings towards one another over the same distance.
In an example, the interconnection part is configured to be in electrical connection with the movable contact of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with the movable contact of the second vacuum interrupter during at least part of the transition from the closed state to the open state.
In an example, the interconnection part is configured to be in electrical connection with the movable contact of the first vacuum interrupter and the interconnection part is configured to be in electrical connection with the movable contact of the second vacuum interrupter during the transition from the closed state to the open state.
In an example, the current path between the movable contacts is provided by at least one wall of the interconnection part.
In an example, one or more of the at least one wall of the interconnection part comprises ribs on the inner side and/or on the outer side.
In an example, the interconnection part is open on a first side.
In an example, the interconnection part is open on a second side opposite to the first side.
In an example, the interconnection part consists of several elements.
In an example, the circuit breaker further comprises a housing surrounding the first vacuum interrupter, the second vacuum interrupter and the interconnection part. The housing is spaced from the at least one wall of the interconnection part. This provides at least one gap.
In an example, a mounting between the actuator and the housing comprises at least one support insulator or other mechanical structure that ensures sufficient mechanical strength during switching operations of the breaker.
Therefore, a series connection of two VIs, each that can be designed for a lower voltage than a full voltage requirement of the overall circuit breaker, provides for an easier alternative to a single VI designed for higher voltage and provides for a more robust interruption due to a double gap arrangement provided by each VI.
In an example, the vacuum interrupters connected in series are not of the same or equal design.
In an example, the lever system and/or housing and/or interconnection parts are not symmetrically designed and/or connected to both vacuum interrupters used.
Thus, a design is provided with an interconnection part, which is a part interconnecting two vacuum interrupters (VIs) that are electrically connected in series. This interconnection part interconnecting the two VIs is designed not only for current carrying functionality, but at the same time provides for improved heat exchange and provides for mechanical fixation of the movable parts like current carrying flexible part or sliding current connection to the movable contacts and provides for support means for a lever system that is used to move the movable contacts. The housing is used to improve the dielectric withstand between two phases/poles as well as for the higher mechanical strength. Furthermore, the interconnecting part can be connected to or associated with a heat pipe device to lead the heat from that “hot spot” area to an area where the heat dissipation at the switchgear can be done. That will give the opportunity to increase further the rated current flow throughout the interconnecting part. The heat pipe can be placed even on both ends of the first and the second VI to lower the temperature on both pole ends.
In a second aspect, there is provided a medium voltage or high voltage switchgear comprising at least one circuit breaker according to the first aspect.
The above aspects and examples will become apparent from and be elucidated with reference to the embodiments described hereinafter.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22180589.8 | Jun 2022 | EP | regional |
