ES2630405T3 - Gas insulated medium voltage disconnect switch - Google Patents

Abstract

Gas-insulated medium voltage disconnect switch (1): - a gas-tight housing (2) with an insulating gas; - for each phase, a mobile contact, a fixed contact and a grounding contact positioned within said housing; - an operating mechanism (3) for moving said mobile contact between open, closed and grounded positions; said gas-tight housing (2) comprises a first upper half-cover (21) and a second lower half-cover (22) coupled in a gas-tight manner, one of said first and second half-covers (21, 22) is made of metal material , the others made of polymeric material, characterized in that said semi-cover made of metal material is grounded, said disconnecting switch (1) comprises, for each phase, a first bearing bushing (41) associated with said first semi-covered upper (21) and a second bearing bushing (42) associated with said second semi-covered (22), said first bearing bushing supports said fixed contact and said second bushing bushing supports said mobile contact.

Description

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Gas insulated medium voltage disconnect switch

[0001] The present invention relates to a gas-insulated medium voltage disconnecting switch, in particular, a three-phase, multi-purpose three-position disconnecting switch with integrated grounding switch suitable for medium voltage.

The disconnect switches of the invention are typically used in medium voltage switch within secondary distribution substations for supply lines, power transformers and networks.

[0002] Gas insulated medium voltage disconnect switches are known in the art. These usually consist of a gas-tight housing that defines an internal space filled with an insulating gas and houses, for each phase, one or more mobile contacts and one or more corresponding fixed contacts.

In a typical application, a disconnecting switch comprises for each phase, a mobile contact, a fixed contact and a grounding contact, the mobile contact can be moved between open, closed and grounded positions.

[0003] Depending on the intended application, disconnecting switches need to satisfy a number of requirements that frequently the same disconnecting switches cannot meet.

For example, it is generally desirable to have a disconnecting switch that is as compact as possible to occupy the minimum possible space in the installed unit.

In some cases, it is necessary to have a segregation connected to metallic ground between the upper and lower compartment of the unit and this is generally achieved using a disconnecting switch provided with a stainless steel housing.

On the other hand, in such a case, the need to maintain a minimum electrical distance from the busbar does not allow the disconnecting switch to be placed too close to the busbars themselves, with a consequent waste of internal space in the unit.

[0004] Therefore, it is necessary to have a number of switch disconnectors made according to the intended application, in terms of size and performance, with a consequent increase in design and manufacturing costs.

This lack of standardization has another drawback in manufacturing costs, as well as in maintenance costs, since it is necessary to have a number of different components and spare parts according to the different types of disconnecting switch.

[0005] Therefore, it is an object of the present invention to provide a disconnecting switch that is highly standardized (in terms of characteristics, size and performance), in the sense that this can satisfy a number of different requirements, so that its use is possible in a number of different applications that a single team cannot cover today.

[0006] More in particular, it is an object of the present invention to provide a disconnecting switch that allows to minimize the space occupied within the unit installed therein and which at the same time can satisfy the requirements of the relevant standards, for example, segregation grounded metal between the compartments of the unit.

[0007] As another object, the present invention is intended to provide a disconnecting switch with the maximum possible number of standardized components, so as to reduce manufacturing and maintenance costs.

[0008] EP 0 485 306 A1 discloses a housing of two plastic covers for a gas-insulated medium voltage disconnecting switch.

[0009] FR 2 259 459 discloses a gas-insulated medium voltage disconnecting switch, according to the preamble of claim 1.

[0010] Thus, the present invention relates to a gas insulated medium voltage disconnecting switch, as defined in claim 1.

[0011] In this way, it is possible to overcome some of the disadvantages and disadvantages of isolated gas isolating switches known in the art. Thanks to the fact that one of the half shell is made of polymeric material, it is possible to have a reasonable compact size of the shell in general, particularly if the bearings are integrated with said half shell made of polymeric material, as described below.

Furthermore, since the polymeric material is insulating, it is possible to reduce the electrical distance from, for example, the busbars, so that the volume occupied in a panel is reduced.

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[0012] At the other end, since a half-casing is made of metal material and grounded, because a segregacon connected to metallic ground between the top and bottom of the unit where the switch is installed disconnector, for example, is achieved between the busbar compartment and the feeder compartment of a switch under metal enclosure.

In addition, segregation connected to metallic earth, provided by the half-shell made of metal material, considerably reduces the possibility of a short circuit between the phases and between the upper and lower contacts of the same phase, due to leakage currents.

Also, the metallic material guarantees a safe performance in case of internal failure.

[0013] A medium voltage switch, which includes a disconnecting switch according to the general definition provided above is also part of the present invention.

[0014] Other features and advantages of the invention will emerge from the description of preferred but not exclusive embodiments of the disconnecting switch according to the invention, non-limiting examples of which are provided in the accompanying drawings, where:

Figure 1 is a perspective view of a possible embodiment of a disconnecting switch, according to the invention;

Figure 2 is a perspective view of the housing of the switch disconnector of Figure 1, showing the first half-cover separated from the second half-cover;

Figure 3 is a detailed view of the first upper half cover of the disconnecting switch, according to Figure 2;

Figure 4 is a detailed view of the second lower half cover of the disconnecting switch, according to Figure 2;

Figure 5 is a view of the second lower half cover of the disconnecting switch of Figure 4, with the lower bearing removed from the same half cover;

Figure 6 is a partial front view of a medium voltage switch in which a disconnecting switch has been installed, according to the invention.

[0015] In relation to the aforementioned figures, the gas insulated medium voltage disconnecting switch, according to the invention, designated with reference number 1, comprises a gas-tight housing 2 containing an insulating gas.

Insulation gases, such as SF6, are well known and generally used in the art and will not be described herein.

The disconnecting switch also comprises, for each phase, a mobile contact, a fixed contact and a grounding contact (not shown in the attached figures) that are positioned within said housing.

In the embodiments of the attached figures, a three-phase disconnecting switch is shown, with a corresponding number of mobile contacts, fixed contacts and grounding contacts.

[0016] An operative mechanism 3 (shown only in Figure 6) is generally used for the movement of said mobile contact between open, closed and grounded positions, according to well known procedures.

The housing can also include a pressure gauge, an exhaust valve or, in general, a pressure relief system for any gas overpressure, as well as one or more inspection windows for visual control of the contact position.

[0017] As clearly shown in the figures, the gas-tight housing 2 comprises a first upper half-cover 21 and a second lower half-cover 22, which are installed in one another in a gas-tight manner.

In the secconator switch of the invention, one of two half-covers 21, 22 is made of metal material, while the rest are made of polymeric material.

[0018] The upper half cover 21 and the lower half cover 22 advantageously comprise a flanged portion, respectively 210 and 220, for the mutual interface between them.

Said parts with flanges 210 and 220 may comprise one or more housings for sealing means, such as gaskets, and may have coupling and fixing means for maintaining the two semi-covers 21 and 22 connected in a hermetic manner. algae.

As an example, threaded means can be used for fixing the semi-covers 21,22.

[0019] Preferably, for each phase, the dryer switch comprises a first bearing bushing 41 associated with said first upper half-cover 21 and a second bearing bushing 42 associated with said second lower half-cover 22.

[0020] According to a preferred embodiment, the first upper half cover 21 is made of polymeric material and the second lower half cover 22 is made of metal material.

In this way, due to the grounded metal segregation provided by the semi-covered

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bottom made of metal, it is possible to access the bottom compartment even if the busbars are low voltage.

[0021] As for the material, the polymeric material used for one of the two semi-shells may be an epoxy resin; obviously other types of polymeric materials can be used, according to the needs.

The metallic material used for the other of the two semi-covers can be steel, for example, stainless steel or pre-galvanized steel.

[0022] With reference to Figures 2 and 3, in a particularly preferred embodiment of the drying switch 1 according to the invention, the semi-cover made of polymeric material comprises, for each phase, a bearing bushing made of one piece, that is to say , the semi-covered 21 and the three bearings 41 have been made in a single piece.

As shown in the aforementioned figures, in this way it is possible to have a very compact structure of the semi-cover 21, so that the requirements of electrical distance with respect to the busbar are maintained at the same time.

[0023] On the contrary, as shown in Figures 4 and 5, the drying switch 1 of the invention comprises, for each phase, a bearing bushing 42 assembled with said semi-cover 22 made of metal material, that is, three bearing bushings 42 for the three-phase dryer switch of the attached figures.

In such a case, holes are provided in the lower part of the lower half-cover, which allow free passage of the contact terminals, and the bearing bushing is assembled to the half-covered 22 to maintain gas-tight conditions.

Advantageously, the bearing bushing may comprise, integrated in its structure, a voltage indicator.

[0024] According to a preferred embodiment, the first bearings 41 hold the fixed contact (not shown) positioned within the housing 2, while the second bearings 42 hold the mobile contact (not shown) also positioned within the housing 2.

For example, the mobile contact can be a blade supported by a pivot by the terminal 420 of the bearing bushing 42, said blade can move between a nearby position, where it is coupled with the corresponding fixed contact, a grounding position where it couples with a corresponding earthing contact and an opening position, where it is not coupled to said fixed or earthing contacts.

[0025] A drive shaft (not shown) is normally propordonated and connects three mobile contacts to the operating mechanism 3 which, as shown in Figure 6, is externally located to the housing 2.

[0026] Preferably, said semi-cover 22 made of metal material is grounded.

In such a case, the grounding contact (not shown) is connected to said half-cover 22 made of metal material.

[0027] With reference to Figure 6, the present invention, according to a second aspect, also refers to a medium voltage switch 10, said switch comprises a disconnecting switch 1, as defined above.

[0028] Preferably, the medium voltage switch 10 according to the invention comprises a housing 101 defining an internal space.

The disconnect switch 1 is generally positioned within said housing 101 to divide said internal space into a first upper compartment 110 and a second lower compartment 120.

The operating mechanism 3, to move the mobile contacts of the disconnecting switch between open, closed and grounded positions, is normally positioned outside the housing 101 and is connected to said mobile contact through a transmission shaft.

The upper compartment 110 may be for example the busbar compartment, while the lower compartment 120 may be the feeder or cable compartment.

[0029] Since one of the two half-covers, for example, the lower half-cover 22, is made of metal material, the disconnecting switch 1 provides a grounded metal segregation between said first upper compartment 110 and said lower second compartment 120.

At the same time, as shown in Figure 6, the extremely compact structure of the first semi-cover 21 made of insulated polymeric material, for example, epoxy resin, allows to reduce the electrical distance with respect to the busbar, so as to minimize the Volume occupied within the same housing.

[0030] The disconnect switch thus conceived can undergo numerous modifications and be of different variants, all within the scope of the invention, as defined in the claims.

In addition, all component parts described herein can be replaced by other technically equivalent elements.

In practice, the components and dimensions of the device materials can be of any nature, according to the need and the state of the art.

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Claims (9)

5 10 fifteen twenty 25 30 35 40 Four. Five 1. Gas insulated medium voltage disconnect switch (1): - a gas tight housing (2) with an insulating gas; - for each phase, a mobile contact, a fixed contact and a grounding contact positioned within said housing; - an operative mechanism (3) for moving said mobile contact between open, closed and grounded positions; said gas-tight housing (2) comprises a first upper half-cover (21) and a second lower half-cover (22) coupled in a gas-tight manner, one of said first and second half-covers (21,22) is made of metal material , the others made of polymeric material, characterized in that said semi-cover made of metal material is grounded, said disconnecting switch (1) comprises, for each phase, a first bearing bushing (41) associated with said first semi-covered upper (21) and a second bearing bushing (42) associated with said second semi-covered (22), said first bearing bushing supports said fixed contact and said second bushing bushing supports said mobile contact. 2. Switch disconnector (1), according to claim 1, characterized in that said first upper half-cover (21) is made of polymeric material and said second lower half-cover (22) is made of metal material. 3. Switch disconnector (1), according to one or more of the preceding claims, characterized in that said polymeric material is an epoxy resin and said metallic material is steel. 4. Switch disconnector (1), according to one or more of the preceding claims, characterized in that said semi-cover made of polymeric material comprises, for each phase, a bearing bushing made of one piece. 5. Switch disconnector (1), according to one or more of the preceding claims, characterized in that it comprises, for each phase, a bearing bushing assembled with said semi-cover made of metal material. 6. Switch disconnector (1), according to claim 1, characterized in that said grounding contact is connected to said half-cover made of metal material. 7. Medium voltage switch (10), characterized in that it comprises a disconnecting switch (1), according to any of claims 1-6. 8. Medium voltage switch (10), according to claim 7, characterized in that it comprises a housing (101) defining an internal space, said disconnecting switch (1) is positioned within said housing (101) and divide said internal space into a first upper compartment (110) and a second lower compartment (120). 9. Medium voltage switch (10) according to claim 10, characterized in that said disconnecting switch (1) provides a grounded metal segregation between said first upper compartment (110) and said lower second compartment (120) .