Compartments for medium voltage air or gas insulated switchgear

Abstract

The present invention relates to a compartment for medium voltage air or gas insulated switchgear. The compartment comprises a plurality of walls. At least one of the plurality of walls is an outer wall. The outer wall comprises a first metal plate. The outer wall comprises a plurality of heat conducting elements. A first surface of the first metal plate is an outer surface configured to be in thermal contact with surrounding air. A second surface of the first metal plate is an inner surface configured to be in thermal contact with air or gas in the compartment. A plurality of heat conducting elements extend from the second surface of the first metal plate into the compartment.

Description

Technical Field

[0001] The invention relates to a compartment for a medium voltage air or gas insulated switchgear and to a medium voltage air or gas insulated switchgear comprising such a compartment. Background Art

[0002] One of the key performance criteria for air or gas insulated switchgear is the ability to conduct the rated busbar and / or t-off currents without overheating any component of the switchgear beyond the temperature rise limits given by the standards and / or the design of such components.

[0003] In switchgear, ohmic and other power losses in the current path release heat. This heat raises the temperature of the current path and other structures of the switchgear. This temperature rise is limited by standards and / or component limits.

[0004] High temperatures can also cause degradation of structural materials such as insulation.

[0005] These issues need to be addressed. Summary of the invention

[0006] It would therefore be advantageous to have an improved technique for providing cooling to compartments of medium voltage air or gas insulated switchgear.

[0007] The objects of the invention are solved by the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims.It should be noted that the compartment is described for medium voltage air or gas insulated switchgear, but is also useful in case of other compartments housing heat generating components.

[0008] In one aspect, there is provided a compartment for a medium voltage air or gas insulated switchgear, the compartment comprising:

[0009] -Multiple walls.

[0010] At least one of the plurality of walls is an outer wall. The outer wall comprises a first metal plate. The outer wall comprises a plurality of heat-conducting elements. The first surface of the first metal plate is an outer surface configured to be in thermal contact with surrounding air. The second surface of the first metal plate is an inner surface configured to be in thermal contact with air or gas in the compartment. The plurality of heat-conducting elements extend from the second surface of the first metal plate into the compartment.

[0011] In an example, a plurality of thermally conductive elements are in thermal contact with the first metal plate.

[0012] In an example, a plurality of thermally conductive elements extend from the first surface of the first metal plate and are configured to be in thermal contact with surrounding air.

[0013] In an example, the outer wall includes a second metal plate. The second metal plate is spaced apart from the first metal plate. A first surface of the second metal plate faces a second surface of the first metal plate. A plurality of heat conducting elements extend from the first surface of the second metal plate.

[0014] In an example, a plurality of thermally conductive elements are in thermal contact with the second metal plate.

[0015] In an example, the second surface of the second metal plate is located on a side of the second metal plate opposite to the first surface of the second metal plate.A plurality of thermally conductive elements extend from the second surface of the second metal plate.

[0016] In an example, the plurality of thermally conductive elements are separated into two or more parts of the outer wall.

[0017] In examples, two or more parts of the outer wall are separated vertically, horizontally or diagonally.

[0018] In an example, each of the two or more components is configured to align with one or more elements of each of two or more phases of the switchgear.

[0019] In an example, a plurality of thermally conductive elements are maintained separated between the first metal plate and the second metal plate.

[0020] In an example, the first metal plate and the plurality of thermally conductive elements are formed from a single metal piece.

[0021] In an example, the outer wall is formed from a single metal piece.

[0022] In an example, a plurality of thermally conductive elements extend through a corresponding plurality of holes in the first metal plate.

[0023] In an example, a plurality of thermally conductive elements extend through a corresponding plurality of holes in the second metal plate.

[0024] In a second aspect, there is provided a medium voltage air or gas insulated switchgear, the medium voltage air or gas insulated switchgear comprising:

[0025] - a compartment according to the first aspect; and

[0026] - Two or more phases.

[0027] One or more components of each of the two or more phases are housed in the compartments.

[0028] The above aspects and examples will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Exemplary embodiments will be described below with reference to the following drawings:

[0030] Figure 1A schematic diagram showing an example of a compartment for a medium voltage air or gas insulated switchgear;

[0031] Figure 2 A schematic diagram showing two views of the outer wall of a compartment for medium voltage air or gas insulated switchgear;

[0032] Figure 3 A schematic diagram showing the outer wall of a compartment for medium voltage air or gas insulated switchgear;

[0033] Figure 4 A schematic diagram showing three outer walls of a compartment for medium voltage air or gas insulated switchgear;

[0034] Figure 5 A schematic diagram showing two outer walls of a compartment for medium voltage air or gas insulated switchgear;

[0035] Figure 6 A schematic diagram showing two outer walls of a compartment for a medium voltage air or gas insulated switchgear; and

[0036] Figure 7 A schematic diagram showing the outer wall of a compartment for a medium voltage air or gas insulated switchgear is shown. DETAILED DESCRIPTION

[0037] Figures 1 to 7 A compartment for medium voltage air or gas insulated switchgear is disclosed. According to an example, the compartment includes a plurality of walls. At least one of the plurality of walls is an outer wall. The outer wall includes a first metal plate. The outer wall includes a plurality of heat conducting elements. A first surface of the first metal plate is an outer surface configured to be in thermal contact with surrounding air. A second surface of the first metal plate is an inner surface configured to be in thermal contact with air or gas within the compartment. A plurality of heat conducting elements extend from the second surface of the first metal plate into the compartment.

[0038] According to an example, a plurality of heat conducting elements are in thermal contact with the first metal plate.

[0039] According to an example, a plurality of thermally conductive elements extend from the first surface of the first metal plate and are configured to be in thermal contact with surrounding air.

[0040] According to an example, the outer wall includes a second metal plate. The second metal plate is spaced apart from the first metal plate. A first surface of the second metal plate faces a second surface of the first metal plate. A plurality of heat conducting elements extend from the first surface of the second metal plate.

[0041] According to an example, a plurality of heat conducting elements are in thermal contact with the second metal plate.

[0042] According to an example, the second surface of the second metal plate is located on a side of the second metal plate opposite to the first surface of the second metal plate.A plurality of heat conducting elements extend from the second surface of the second metal plate.

[0043] According to an example, the plurality of heat conducting elements is separated into two or more parts of the outer wall.

[0044] According to an example, two or more parts of the outer wall are separated vertically, horizontally or diagonally.

[0045] According to an example, each of the two or more portions is configured to align with one or more elements of each of two or more phases of the switchgear.

[0046] According to an example, the plurality of thermally conductive elements remain separated between the first metal plate and the second metal plate.

[0047] According to an example, the first metal plate and the plurality of heat conducting elements are formed from a single metal piece.

[0048] According to an example, the outer wall is formed from a single metal piece.

[0049] According to an example, a plurality of thermally conductive elements extend through a corresponding plurality of holes in the first metal plate.

[0050] According to an example, a plurality of thermally conductive elements extend through a corresponding plurality of holes in the second metal plate.

[0051] As can be clearly seen from the above, the above compartment can be part of a medium voltage air or gas insulated switchgear. The switchgear can have two or more phases. For example, the switchgear can be a three-phase system. One or more components of each of the two or more phases are accommodated in the compartment.

[0052] In an example, one or more components of each of the two or more phases are aligned with different portions of the outer wall of the compartment having the separate thermally conductive element.

[0053] Continuing to refer to the accompanying drawings, Figure 1 As shown in, in the compartments for medium voltage air or gas insulated switchgear, cooling is important because a lot of heat is released during operation. The main heat sources are busbars and T-off joints, as well as one or more circuit breakers and circuit breaker contacts, as well as current transformers and cable terminals. The new compartment design described here enables improved heat dissipation, thereby increasing the available (nominal) continuous current rating, and the improved cooling enables an increase in the permissible load and / or possible savings in current path material.

[0054] like Figures 2 to 3As shown in , the new compartment design has new outer walls, such as the rear wall. This provides improved cooling of the instrument transformer and also enables improved cooling of the busbar and circuit breaker compartments. The new wall has two heat-conducting metal plates connected to heat-conducting elements. These elements transfer heat from inside the switchgear to the outside. The inner metal plates also improve the panel performance in the event of an internal arc fault by shielding the rear wall structure. The new wall is also structurally stronger than the existing wall, and the heat-conducting elements can extend through holes in the inner wall section or the outer wall section of the outer wall, but the double wall structure compensates for such holes in the outer wall.

[0055] like Figures 4 to 7 As shown in , the heat conductive metal plate can be configured in many variations. Figure 4 As shown in , it is possible to arrange the heat-conducting element in one component, or the heat-conducting element can be separated or divided into two or three components in order to align with the internal components of the switchgear. Thus, the heat-conducting element can be separated vertically, horizontally or diagonally. These arrangements are intended to improve airflow and heat exchange. Variants of the heat-conducting element can pass through the outer wall and be separated in order to maintain a distance between the inside of the heat-conducting metal plate and the outer plate of the outer wall. The heat-conducting element itself can be part of the heat-conducting metal plate (forming a one-piece solution).

[0056] In this way, the new wall design improves cooling of the switchgear by increasing energy flow through the outer wall (such as the rear wall) of the switchgear, thereby providing a temperature reduction relative to a new designed compartment without walls, while maintaining the mechanical strength of the outer wall structure.

[0057] In essence, the inventors realised that, for example in a switchgear compartment (such as a cable compartment), heat is exchanged with the surrounding environment in multiple ways, one of which is through a metal outer wall (such as a rear wall), which typically has a large area, and that this heat transfer can be improved by a new design of the outer wall.

[0058] With the new wall design, the energy flow through the outer wall (e.g. rear wall) is improved by using heat exchange surfaces of increased area, inside and outside the outer wall. A material with a better thermal conductivity than the steel material of the wall itself can be used to make the heat flow through the wall. However, if desired, the wall and the heat-conducting element can be formed from a single piece. The holes for the heat-conducting element do not affect the strength of the wall in any significant way in terms of its mechanical properties (e.g. for internal arc testing).

[0059] Thus, in summary, there are two heat exchanging metal plates connected by a heat conducting element. The metal plates may be a single piece and may be split horizontally, vertically or in some other manner. The metal plates and the heat conducting elements may be replaced by a single piece solution, where both the inner and outer metal plates as well as the heat conducting elements are replaced or formed from a single piece of material. The new design is based on a development of the design of the outer wall (e.g. rear wall) of the current switchgear compartment. Additional heat conducting elements are fixed to the outer wall, so that the elements in the switchgear take away heat from the hot air inside and conduct the heat to the external heat conducting element, which heats the outside air and thereby cools the interior of the compartment. The heat conducting elements are fixed so as to maintain an appropriate or desired distance between the two metal plates. These heat conducting elements may have various sizes and appearances.

[0060] Each outer wall of a compartment may be formed with a new wall design.

Claims

1. A compartment for a medium voltage gas insulated switchgear, the compartment include: - multiple walls; wherein at least one of the plurality of walls is an outer wall; Wherein, the outer wall comprises a first metal plate; wherein the outer wall comprises a second metal plate, wherein the second metal plate is spaced apart from the first metal plate, Wherein, the outer wall includes a plurality of heat-conducting elements; wherein the plurality of thermally conductive elements are in thermal contact with the first metal plate, and wherein the first metal plate and the plurality of thermally conductive elements are formed from a single piece of metal; wherein the plurality of thermally conductive elements are in thermal contact with the second metal plate, and wherein the plurality of thermally conductive elements extend through a corresponding plurality of holes in the second metal plate; wherein the first surface of the first metal plate is an outer surface configured to be in thermal contact with surrounding air; wherein the plurality of thermally conductive elements extend from the first surface of the first metal plate and are configured to be in thermal contact with the surrounding air; wherein the second surface of the first metal plate is an inner surface configured to be in thermal contact with the gas in the compartment; wherein the plurality of heat conductive elements extend from the second surface of the first metal plate into the compartment; wherein the first surface of the second metal plate faces the second surface of the first metal plate, and wherein the plurality of thermally conductive elements extend from the first surface of the second metal plate; The second surface of the second metal plate is located on a side of the second metal plate opposite to the first surface of the second metal plate, and the plurality of heat conducting elements extend from the second surface of the second metal plate.

2. The compartment according to claim 1, wherein the plurality of thermally conductive elements are separated into two or more parts of the outer wall.

3. The compartment according to claim 2, wherein the two or more parts of the outer wall are separated vertically, horizontally or diagonally.

4. A compartment according to any one of claims 2 to 3, wherein each of the two or more components is configured to align with one or more elements of each of two or more phases of the switchgear.

5. The compartment according to any one of claims 1 to 3, wherein the plurality of thermally conductive elements are kept separated between the first metal plate and the second metal plate.

6. A compartment according to any one of claims 1 to 3, wherein the outer wall is formed from a single piece of metal.

7. The compartment of any one of claims 1 to 3, wherein the plurality of thermally conductive elements extend through a corresponding plurality of holes in the first metal plate.

8. A medium voltage gas insulated switchgear, include: - A compartment according to any one of claims 1 to 7; as well as - two or more phases; as well as wherein one or more components of each of the two or more phases are accommodated in the compartment.

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