EP2132757A1

EP2132757A1 - Gas-insulated switchgear device

Info

Publication number: EP2132757A1
Application number: EP08717906A
Authority: EP
Inventors: Vittorio Gargioni; Pierernesto Gatti; Roberto Cameroni
Original assignee: ABB Technology AG
Current assignee: ABB Schweiz AG
Priority date: 2007-03-30
Filing date: 2008-03-17
Publication date: 2009-12-16
Anticipated expiration: 2028-03-17
Also published as: WO2008119655A1; EP2132757B1; CN101641755A; CN101641755B

Abstract

A gas-insulated switchgear device which comprises a supporting structure having a base adapted for placement on a supporting surface and one or more poles. Each pole comprises a first casing housing at least a first terminal for input/output connection, a disconnector unit comprising at least a first fixed contact operatively coupled to the first terminal and a corresponding first movable contact, and a circuit breaker unit electrically connected to the disconnector unit and having a couple of interruption contacts which can be actuated along a longitudinal reference axis during operation of said circuit breaker. Each pole is mounted on the supporting structure with the longitudinal reference axis transversal with respect to the supporting surface.

Description

GAS-INSULATED SWITCHGEAR DEVICE

The present invention relates to a gas-insulated switchgear device for high- or medium- voltage applications, i.e. for applications with nominal operating voltages above 1000V, having improved functions and characteristics. Further, the present invention relates also to an electric power station or substation comprising such a gas-insulated switchgear device. It is well known in the art that along the path of a power grid there are provided several electric substations for transmitting and distributing electricity from a power generating source to loads and users connected to the feeding grid; these substations may be configured according to different layouts depending on the applications, and are realized by using a series of electric components, such as disconnectors, circuit breakers, instrument transformers, control systems.

According to more traditional solutions, electric substations are realized by using several components which are structurally independent and suitably connected to each other and to the power line when assembling in order to obtain the required layout and to perform each a respective dedicated function; these traditional solutions have presented some drawbacks in practical use, mainly due to the large number of components required, even for providing a minimal configuration, and to their structural and functional separation. Indeed, these aspects result in heavy maintenance requirements for each and any of the components used, and to a considerable increase of the overall dimensions of the substation, with a consequent negative impact on installation and maintenance costs, as well as on environmental impact. To overcome the above mentioned drawbacks, in recent years a new generation of compact gas-insulated switchgear devices has been designed which integrate in a unique apparatus and are able to perform several electrical functions which, in the prior substations, were obtained by using multiple structurally separate elements. In particular, these new devices comprise an external casing on which there are mounted two or three bushings each containing a corresponding electric terminal for input/output connections with a power line and/or other elements of the substation; inside the casing there are normally provided one or more disconnection units and one or more interruption units, which are electrically connected to each other and to the electric terminals, in such a way that electrical disconnection and/or circuit breaker maneuvers are performed in a coordinated way.

Some examples of such gas-insulated switchgear devices are disclosed in US patent no. 5,796,060, European granted patents EPl 121739, EP1218995.

This type of switchgear devices has significantly contributed to reduce the number of components needed, thus allowing to realize more compact substations with less environmental visual impact, and to reduce installation and maintenance costs.

Although these new devices have provided substantial benefits and improvements, there is still the need and room for further optimization. In particular, customarily requirements demand for improved solutions as regard to space/land occupation, easiness of mounting/ dismantling of the whole devices or part thereof. In addition, requirements for solutions offering the highest level possible of safety for operators have luckily become more and more demanding.

Thus, it is desirable to provide a solution which meets these requirements and allows further improvements of the actual prior art devices and applications. This solution is provided by a gas-insulated switchgear device of the present invention as defined in the appended claims. Further, the present invention also provides an electric station or substation comprising such a gas-insulated switchgear device and more particularly a wind power generation station having a wind tower which houses such a gas-insulated switchgear device. Further characteristics and advantages of the present invention will become better apparent from the description of preferred but not exclusive embodiments of a gas-insulated switchgear device according to the invention, illustrated only by way of non- limitative examples in the accompanying drawings, wherein: figure 1 is a side view illustrating an embodiment of a pole of the gas-insulated switchgear device according to the invention; figure 2 is a partial cross-section view of the switchgear device of figure 1; figure 3 illustrates in greater details part of the portion circled of figure 2; figure 4 is a view schematically illustrating another embodiment of a pole of the gas- insulated switchgear device according to the invention; figure 5 is a perspective view showing the gas-insulated switchgear device according to the invention seen from the front in a three-pole configuration; figure 6 is a perspective view showing the gas-insulated switchgear device of figure 5 seen from the back; figure 7 is a perspective view schematically illustrating part of the base of a supporting structure used in the switchgear device according to the invention coupled with a hinge device; figure 8 shows the device of figure 5 with one of the poles being dismantled; figure 9 is a perspective view illustrating a possible embodiment of a supporting structure of the switchgear device according to the invention; figure 10 is a lateral view of part of an electric power station showing the switchgear device according to the present invention coupled with a power transformer; figure 11 is a top view the station illustrated in figure 10; figure 12 schematically shows a portion of a wind tower with a switchgear device according to the invention positioned inside the tower itself; figure 13 shows a container housing a power transformer and switchgear device according to the invention which are mutually coupled; figure 14 schematically shows an alternative embodiment of a pole of the switchgear device according to the present invention.

With reference to the above cited figures, the high- or medium-voltage gas-insulated switchgear device according to the invention comprises a supporting structure globally indicated by the reference number 300 and one or more poles, e.g. three poles as shown in the appended figures. Clearly, the number of poles can be modified according to the application.

As illustrated in figure 9, the supporting structure 300 comprises a plurality of members, for example U- or C or L shaped metallic elements, which are assembled to each other, e.g. by soldering, or screwing, or both. The profiled assembled elements define a frame having a base 301 adapted for placement on a supporting surface 302, such as a pavement, a concrete pad, another metallic base, land or any other suitable placement surface. In addition, the assembled members define at least one surface for mechanical connection with the one or more poles in the way that will be further described hereinafter. In particular, as shown in the embodiment of figure 9, the assembled profiled members of the supporting structure 300, in addition to the base 301, define also a lateral wall or side 303 and a main or front side or wall 304. The base 301 comprises for example two parallel profiled members 310 which are connected at one side by a profiled cross member 306. The lateral side 303 is formed for example by two vertical uprights 305 and 307 which are connected to each other by some profiled cross members 306, e.g. four, and are connected each at a corresponding end of the two members 310. The upright 307 is part of the front wall 304 which further comprises a third upright 308. The uprights 307 and 308 are connected to each other by one of the members 310 and by some profiled members 311, 312, 313 which are spaced apart from each other and from said one member 310. One or more of the profiled members 311, 312, 313, for example at least the member 311 has a substantially flat surface provided with holes 314.

As illustrated for example in figures 1-2, each pole comprises a first fixed casing 1 which can be realized in one single piece or more pieces connected together and is partially or totally filled with an electric insulating gas, e.g. SFβ, and extends along a longitudinal axis . The casing 1 houses at least a first terminal or bar 5 for electrical input/output connections of the switchgear device with a power line and/or other electrical equipments, such as transformers, loads, et cetera. Preferably, as shown in figure 1, the switchgear device according to the invention comprises a second terminal 6 for input/output connection. Further, when for example the switchgear device is devised to realize a layout of the so- called double bus-bars type, it comprises a third terminal 70 for input/output connection, as schematically shown in figure 4. The connections between each terminal and the associated component, e.g. the power line or any other electric equipment, such as a power transformer, can be realized by means of bushings which are connected to the pod- shaped portion 2 of the casing 1 and house the connecting conductors, or cables 201 or both. For example, in the embodiments of figures 1, 2 and 4, for each terminal 5, 6 and 70 there is provided a corresponding bushing, 3, 4 and 7, respectively. In the embodiment shown in figures 10 and 11 one of the input/output connections is realized by using a cable 201, and another connection is realized using a bushing 3. As schematically represented in the embodiment application of figure 12, all connections are realized by using cables 201.

Inside the casing 1 there is a disconnector unit having at least a first fixed contact 8 electrically coupled to the first terminal 5, and a corresponding first movable contact 9 which can be actuated, during operation of said disconnector unit, so as to electrically connect/disconnect with/from the first fixed contact 8; in the embodiments illustrated, the disconnector unit preferably comprises also a second fixed contact 14 electrically coupled to the second terminal 6 and a corresponding second movable contact 15. According to the embodiment illustrated in figure 4, the disconnector unit comprises a third fixed contact 71 which is operatively connected to the corresponding third terminal 70; accordingly, the disconnector unit comprises a third movable contact 72 which can be electrically connected/disconnected with/from the third fixed contact 71. Alternatively, the disconnector unit can have the second movable contact 15 which can be suitably arranged so that it can be electrically connected/disconnected either with/from the second fixed contact 14 and also with/from the third fixed contact 71. As shown in figures 1 and 2, the disconnector unit preferably comprises one or more additional fixed earth contacts, e.g. a first 40, a second 41 and a third earth contact 42 mounted on the inner surface of the first casing 1 which is at ground potential; during operations each earth contact 40, 41, 42 can be connected to a corresponding moving contact 9 or 15 or 72 so as to realize ground or earth connections. Some of or all the earth contacts 40, 41, 42 can be placed inside the main part of the casing 1, e.g. along the longitudinal body as shown for example in figures 1 and 2, or can be positioned external to this main part e.g. inside another component which is coupled to the main body of and is part of the casing 1. This another component can be for example a metallic spherical enclosure which is connected to the main body of the casing 1, for instance where a corresponding terminal is placed, e.g. where one bushing is suitable to be mounted. Inside the casing 1 there is also provided a circuit breaker unit which is electrically connected to the disconnector unit and comprises at least a couple of interruption contacts, i.e. a first main contact 10 and a second main contact 11 which, during operation of the circuit breaker unit, can be actuated along a longitudinal reference axis 200, which in practice may preferably coincide or be parallel with the longitudinal axis of the casing 1, between a circuit breaker closed position where they are electrically coupled and a circuit breaker open position, illustrated in figure 2, where they are electrically separated. The circuit breaker unit comprises also arcing contacts 12 and 13 whose structure and functions are well known in the art and therefore not described here in details.

Advantageously, as shown in figures 5-6, each pole is mounted on the supporting structure 300 with its longitudinal reference axis 200 transversal, more preferably vertical i.e. perpendicular, relative to the supporting surface 302. As illustrated in figure 9, the supporting structure 300 features at said base 301 a bearing device which comprises a couple of elements 315, e.g. L-shaped, which extend upwardly from the members 310 of the base, and are connected to each other by a flat plate 316 which extends transversally relative to the reference axis 200. Clearly, the elements 315 can be differently profiled, and the plate 316 can be realized in two or more pieces. In particular, the flat plate 316 is close to and transversal, preferably substantially perpendicular, relative to the flat surface of the profiled member 311. For each pole there is provided a corresponding bearing device. In practice, as illustrated in figure 5, when a pole is coupled to the supporting structure 300, its casing 1 has an end portion which rests on the flat plate 316 of the corresponding bearing device. In addition, the first casing 1 is removably connected to the profiled member 311, e.g. by screwing into the respective holes 314. The first casing 1 comprises an outward protrusion 110 which is connected to a corresponding flat surface of a second profiled member, i.e. the member 312 of the front wall. Also in this case the protrusion 110 can be screwed into the corresponding holes 314.

According to a particularly preferred embodiment, the first casing 1 comprises at least a first porthole 120 for visually checking the position of the first movable contact 9; preferably, the first casing 1 also comprises a second porthole 121 which is spaced apart from the first porthole 120 for visually checking the position of the second movable contact 15. When a pole comprises a third terminal 70 and the disconnector unit comprises the third fixed contact 71 operative Iy coupled to the third terminal and a corresponding third movable contact 72, the first casing 1 may be provided with a third porthole, similar to the portholes 120, 121, for visually checking the position of the third movable contact 72. In particular, each of the earth contacts 40, 41 and 42 for earth connection with the corresponding movable contact 9, 15, 72 is positioned internally on the first casing 1 in such a way that it is visible from outside the first casing 1 through the corresponding porthole 120, 121. In addition, each porthole 120, 121 and the corresponding terminals 5, 6, 70 are positioned on the casing 1 substantially opposite to each other with respect to the reference axis 200, i.e. they are positioned relative to each other so that when the pole is mounted on the supporting structure 300, they face towards opposite directions with respect to the front side 304. In practice, when all poles are mounted on the supporting structure 300, they are positioned substantially vertically and side by side with their respective longitudinal axes 200 lying on a common vertical plane; all portholes 120, 121, are positioned on one half plane, while the terminals for input/output connections are placed on the opposite half plane relative to said common plane.

Alternatively, it is possible to provide only two portholes. In this case, the second porthole 121 will allow visual inspection of the second and third movable contacts 15, 72 as well as of the second and third earth contacts 41 and 42. Also in this case, the second porthole 121 is positioned opposite to the second and third terminals 6, 70 relative to the reference longitudinal axis 200.

As shown in figure 5, the switchgear device according to the invention, further comprises: actuating means for operating the disconnection unit and the circuit breaker unit when executing electrical manoeuvres, e.g. opening/closing of the circuit breaker unit and/or connection/disconnection of the input/output connections; and a second casing unit, globally indicated in figure 1 by the reference number 100, which is operative Iy coupled with said actuating means, which houses the contacts of the circuit breaker unit and on the outer surface of which at least the first movable contact 9 is mounted. The second casing 100 is filled with insulating gas, e.g. SFβ; alternatively, it is possible to fill with a first insulating gas having high dielectric properties, e.g. SFβ, only the second casing 100 which can be hermetically sealed, and to fill the remaining internal volume of the first casing 1 with air or other suitable insulating gases, such as nitrogen (N2), nobles gases, or mixtures. Preferably, the second casing 100 is formed by several pieces solidly connected to each other and forming a unique rotating body; in particular, as illustrated in figures 1-2, its structure advantageously comprises the interruption chamber 101 of the circuit breaker unit which in turn can be formed by one or more pieces solidly connected to each other, an electric shield 102 which is preferably mounted close to a first end of the interruption chamber 101, and a hollow rotating supporting member 103. The second casing 100 is operatively connected to the opposite ends of the first casing 1 by means of rotating shaft means shaft 105 and said member 103 which are connected to the casing 1 by using suitable systems, e.g. bearings, flanges etc. The second casing 100 is preferably pivotally mounted inside the first casing 1 and is operatively coupled to the actuation means so as, when the disconnection unit is operated by the actuating means, it rotates dragging into rotation at least the first movable contact 9, substantially solidly with it; preferably, also the second movable contact 15 and when present also the third movable contact 72 are mounted on the second casing 100, and rigidly rotate with it so that they can be electrically connected/disconnected with/from the corresponding fixed contact(s) 14 (71) during operation of the disconnector unit.

The actuating means are configured and operatively coupled to the couple of main interruption contacts 10-11 and also to the second casing 100 which in practice acts as and constitutes an actuating means as well- in such a way that, when the second casing 100 rotates during operation of the disconnection unit, the main interruption contacts 10-11 remain electrically coupled in the circuit breaker closed position and substantially still relative to each other, i.e. they do not have movement relative to each other (apart from unavoidable mechanical inertia). In a first embodiment, the couple of interruption contacts 10 and 11 are operatively coupled to the actuating means so as to rotate, during rotation of the second casing 100, about the reference longitudinal axis 200, substantially simultaneously to each other (apart from initial unavoidable mechanical inertia), i.e. with the same angular speed, while being electrically coupled in the circuit breaker closed position, and to translate one relative to the other along the longitudinal axis 200 with the casing 100 kept still, during closing/opening operation of the circuit breaker unit. More preferably, the couple of main interruption contacts 10 and 11 are operatively coupled to the actuating means so as to rotate, during rotation of the second casing 100, substantially simultaneously to each other and together with the second casing 100 (apart from initial mechanical inertia). According to this embodiment, the first main contact 10 is solidly connected to the second casing 100 and the actuation means comprise: rotating shaft means, comprising the rotating shaft 105, which are connected to the second casing 100 and are operatively coupled with driving means, e.g. a motor positioned outside the first casing 1, schematically indicated in figure 1 by the reference number 106; and rod-shaped means which comprise a first rod portion 16, for example made of electrically conducting material, which is connected to and supports the main contact 11, and a second rod portion 17, for example made of electrically insulating material, which protrudes outside the first casing 1 and is operatively connected to driving means 107, e.g. another motor. In particular as shown in figure 5, the motors 106 and 107 are connected to the supporting structure 300 at the end portions of the lateral side 303. The first rod 16 portion and the main contact 11 may be realized in a unique piece made of electrically conducting material.

The two portions 16 and 17 are substantially aligned along the longitudinal axis 200 and are operatively connected to each other and to the second casing 100 by suitable coupling means; as illustrated in figures 2-3 said coupling means comprise a first bush 18 which is positioned around facing ends of the first and second rod portions 16-17, and is connected to a first end of the second casing 100. In particular, the bush element 18 is connected to the internal side of the electric shield 102 by interposing sealing means 19, e.g. a ring made of teflon. The coupling means comprise also a first shaped element 20 which is inserted in the first rod portion 16 at an end thereof, and is provided with a first through hole 21 and a second through hole 22 which are arranged transversally with respect to the longitudinal axis 200; preferably, the shaped element 20 has also a contoured head 35 adapted to obstruct an opening 36 provided on the first rod portion 16. The coupling means further comprise: a first pin 23 which passes inside the first through hole 21 and a corresponding hole of the rod portion 16, and is fitted in a receiving seat provided on the first bush 18; a second pin 24 which passes within the second through hole 22 and is fitted inside a receiving seat provided on the first rod portion 16. The pins 23 and 24 allow realizing rigid couplings among the bush element 18, the first rod portion 16, and the shaped element 20. In addition, there are: a first hollow tube 25 which is positioned, along the longitudinal axis 200, inside the second rod portion 17 and at an end thereof; a second hollow tube 26 which is also positioned inside the second rod portion 17 around the first tube 25, and is provided with a through channel 27 extending transversally with respect to the axis 200; a coupling pin 28 which is inserted inside said through channel 27 and is fitted in a seat arranged on the second rod portion 17; the coupling pin 28 has a through opening, directed along the axis 200, receiving the first hollow tube 25. Finally, there is provided a fixing a element, e.g. a screw 29 which passes through the first tube 25, and has a first end portion 30 which is fixed, e.g. screwed onto the first shaped element 20, and a head portion 31 which, by the fixing, is brought to push the first tube 25 in abutment against the first shaped element 20. The operative coupling between the various components is realized so as, when fixing is completed, there is a suitable small clearance between: the second tube 26 and the first tube 25; the facing surfaces of the second tube 26 and the first shaped element 20-the first rod portion 16; the head portion 31 and the second tube 26.

Advantageously, in the device according to the invention there is a unique motor 106 which is connected to and contemporaneously drives all the disconnection units of the various poles used. In particular, as illustrated in figures 5, 6and 8, the motor 106 is operatively connected to the shaft 105 of each pole disconnection unit by means of a modular rod 130, constituted for example by pieces of a tubular element assembled to each other. Likewise, in the device according to the invention, there is a unique motor 107 which is connected to and contemporaneously drives all breaker units of the various poles used. In particular, as illustrated in figures 5, 6 and 8, the motor 107 is operatively connected to the rod 17 of each pole by means of a modular rod 140, constituted for example by pieces of a tubular element assembled to each other.

This solution is particularly advantageous when it is necessary to dismantle one or more of the poles. In particular, in the device according to the invention, the supporting structure 300 can be provided with a hinge device 320 illustrated in figure 7. The hinge device comprises for example a U-shaped element 321 which is fixed to a profiled member 310 of the base 301 and a rod 322 which passes through the lateral side of the U-shaped element 321 and enters into corresponding holes provided in the two members 315 of a bearing device. When a pole must be dismantled, the corresponding portions of the rods 130 and 140 are disconnected from the others and a pulley (schematically indicated in figure 8 by the reference number 501)can be coupled to the supporting structure in order to hold the pole. The screws connecting the elements 315 of the corresponding bearing device are unscrewed from the member 320; in this way, once the screws connecting the casing 1 to the profiled members 311 and 312 are also unscrewed, the pole can be rotated thanks to the hinge device and can be extracted from the supporting frame 300. Alternatively, it also possible to use a profiled track connected to the U-shaped element 321 so as to make the pole sliding along it.

In practice, in normal working conditions, the circuit breaker unit is in a closed position with the contacts 10-11 electrically coupled; each of the movable contacts of the disconnector unit is connected to the corresponding fixed contact, so as all input/output connections are closed. When it is necessary to execute an electrical maneuver, for example opening the circuit breaker unit due to a fault, the driving means 107 drive the second rod portion 17; the second rod portion 17 translates along the axis 200, (arrow 50 in figure 2) and, thanks to the couplings above described, it drags in joint translation with it: the screw 29, the tubes 25-26, the coupling pin 28, the two pins 23-24, the shaped element 20, the bush 18 (which slides on the inner surface of the sealing means 19) the first rod 16, and the second main contact 11 connected to the rod portion 16 which moves away from the first main contact 10; with respect to the second casing 100-first main contact 10-shaft means 105 which instead remain substantially still. At the end of the movement, as illustrated in figure 3, the shaped head 35 is advantageously positioned so as to obstruct the opening 36 thus preventing flowing of the hot gases produced following the opening operation towards the insulating second rod portion 17, and convey such gases in a suitable quenching zone inside the casing 100. Closing of the circuit breaker occurs in an analogous way with the same components jointly translating in the opposite direction (arrow 60 in figure 2). When performing operation of the disconnector unit, the drive means 106 drive the shaft means, and in particular the shaft 105 which rotates, around the axis 200, jointly with: the casing 100, the couple of contacts 10-11 (which remain electrically coupled), the sealing means 19, the bush 18, the shaped element 20, the pins 23-24, the first rod portion 16, the screw 30 and the first tube 25; while the second tube 26, the coupling pin 28 and the second rod portion 17 are maintained substantially still. In its rotation, the second casing 100 drags into rotation the movable contact(s) 9(15,72) of the disconnector unit mounted thereon. In an alternative embodiment, the couple of interruption contacts 10 and 11 are operatively coupled to the actuating means so as, during rotation of the second casing 100, they are kept still, i.e. motionless, and electrically coupled in the circuit breaker closed position, while they translate relatively to each other along the axis 200 during opening/closing operations of said circuit breaker unit while the second casing 100 is kept substantially still. According to this embodiment, the first main contact 10 (as well as the arcing contact 12) is mounted on a suitable supporting member, schematically indicated in figure 2 by the number 108, which is operatively coupled to the casing 100, e.g. at the zone where the rotating shaft 105 is connected with the casing 100; in turn, the second main contact 11 is connected to rod- shaped means, constituted for example a single rod-shaped body, or comprising two separate rod portions rigidly coupled to each other, e.g. the two rod portions 16-17 of the previous embodiment. In this embodiment, the coupling means are configured so as to mechanically connect the second casing 100 on one side with the main contact 10 and the shaft means, and on the other side with the rod-shaped means by realizing a turning kinematic pair during rotation of the second casing 100, and by realizing a sliding kinematic pair during operation of the circuit breaker unit. In particular, said coupling means may comprise at least a thrust bearing; preferably there are provided two thrust bearings, schematically indicated in figure 1 by boxes in dotted lines 80-90, which are positioned for example one inside the electric shield 102 and the other at the opposite end of the first casing 100 at the region where the supporting member 108 is coupled to the casing 100. According to this alternative embodiment, as previously described, when executing opening/closing of the circuit breaker, the driving means 107 drive the rod shaped means which translate along the axis 200 and inside the bearing 90 together with the second main contact 11 which moves away from the first contact 10; the first contact 10 and the casing 100 remain still (sliding cinematic pair with respect to the casing 100). When operating the disconnector unit, the drive means 106 drive the shaft 105 which rotates together with the casing 100 around the axis 200, while, thanks to the thrust bearings 80-90, the contacts 10- 11, the supporting member 108 operatively connected to the casing 100 through the bearing 80, and the rod shaped means remain still with the contacts 10-11 electrically coupled in the circuit breaker closed position (turning cinematic pair of the casing 100 with respect to the ensemble contacts 10-11 -rod shaped means-shaft means). Clearly, possible alternative embodiments may be used as regard to the configuration and of disconnection unit and/or of the circuit breaker unit, and/or their mutual coupling, and also as regard to the positioning and actuation of their contacts. For example, as schematically shown in figure 14, the second casing 100 can be realized in separate pieces not rigidly rotating all together. For instance, there may be provided one piece 101a including the interruption chamber 101 on which the first movable contact 9 of the disconnector unit is mounted and rotates rigidly with it; and a second piece 101b which can rotate independently from the first piece 101 on which the second movable contact 15 and the third movable contact 72, when used, can be mounted.

The gas-insulated switchgear device according to the present invention is particularly suitable for realizing several different types of electric power stations or substations. Hence, the present invention also relates to an electric power station or substation which is suitable to be connected to a power line characterized in that it comprises a gas-insulated switchgear device as previously described and claimed. In particular, figures 10 and 11 show an electric substation comprising a switchgear device according to the invention wherein each pole has a first terminal electrically connected to a power transformer 400 by using a corresponding bushing 3 and a second terminal connected to a power line or to another electrical equipment by using a cable 201. Alternatively, also the first terminal can be connected to the power transformer 400 (or any other electrical equipment) by using a cable 201, as for example schematically represented in figure 13. In particular, as illustrated in figure 13, the gas-insulated switchgear device, and if desired also the transformer 400, can be positioned inside a container 401; this embodiment is particularly useful when the station or substation is placed in an aggressive environment, e.g. in a desert.

Another advantageous aspect resides in the fact that, as shown in figures 10 and 11 the gas- insulated switchgear device is positioned at a distance from and with the terminals of each poles facing the transformer 400; a first protecting net or fence 402 and a second protecting net or fence 403 are positioned at the respective sides of and run from the gas-insulated switchgear device up to the transformer 400. The two fences 402 and 403 laterally delimit an area inside which the electrical connections between the terminal of each pole and the power transformer 400 and the terminal of each pole and a power line or another electrical equipment are positioned and protected. In this way an operator can safely approach the switchgear device from the side where the portholes 102, 121 are provided and visually inspect the position of the disconnector movable contacts of each poles. In this way the operator can personally and directly check, independently from any other possible electric signals, if the contacts are correctly connected to earth, without risking, since the live connections are placed on the opposite side and surrounded by the fences 402, 403. Finally, thanks to its compact structure developing along a vertical plane thus saving land occupation, the gas insulated switchgear device according to the invention is particularly suitable for use in wind power generation station where wind towers are used. Hence, the present invention also relates to a wing power generation station comprising at least one wind tower 500 and characterized in that it comprises a gas-insulated switchgear device as previously described and claimed which is positioned inside the tower 500 as for example schematically illustrated in figure 12.

The switchgear device thus conceived is susceptible of modifications and variations, all of which are within the scope of the inventive concept, all the details may further be replaced with other technically equivalent elements provided they are suitable to perform the required function. For example, the supporting structure can be formed by differently- shaped profiled elements, or others elements such as tubes, or pieces obtained by casting, et cetera; the motors 106 and 107, and where necessary also the relative connection means with the poles, can be placed in other positions, for example vertical, horizontal or parallel relative to the plane on which the axes of the poles lie; the bearing device and/or the hinge device can be differently shaped, et cetera. In practice, the materials, so long as they are compatible with the specific use, as well as the individual components, may be any according to the requirements and the state of the art. In practice, it has been found that the gas-insulated switchgear device according to the invention fully provides the desired aim giving a number of significant advantages and improvements with respect to the prior art devices. Indeed,

Claims

1. A gas-insulated switchgear device characterized in that it comprises: a supporting structure having a base adapted for placement on a supporting surface; one or more poles, each pole of said one or more poles comprising a first casing housing at least a first terminal for input/output connection, a disconnector unit comprising at least a first fixed contact operatively coupled to said first terminal and a corresponding first movable contact which can be electrically connected/disconnected with/from said first fixed contact during operation of the disconnector unit, and a circuit breaker unit electrically connected to said disconnector unit and having at least a couple of interruption contacts which can be actuated along a longitudinal reference axis during operation of said circuit breaker unit between a circuit breaker closed position where they are electrically coupled and a circuit breaker open position where they are electrically separated, wherein each of said one or more poles is mounted on said supporting structure with said longitudinal reference axis transversal with respect to the supporting surface.

2. The switchgear device according to claim 1, characterized in that it each of said one or more poles is mounted on said supporting structure with said longitudinal reference axis substantially vertical with respect to the supporting surface.

3. The switchgear device according to claim 1, characterized in that it said first casing comprises at least a first porthole for visually checking the position of said first movable contact.

4. The switchgear device according to claim 3, characterized in that each pole comprises a first earth contact for earth connection with said first movable contact, said first earth contact being positioned inside said first casing such that it is visible from outside the first casing through said first porthole.

5. The switchgear device according to claim 3, characterized in that said at least first porthole and said first terminal are positioned substantially opposite to each other with respect to said reference axis.

6. The switchgear device according to one or more of preceding claims, characterized in that each pole comprises a second terminal and said disconnector unit comprises a second fixed contact operatively coupled to said second terminal and a corresponding second movable contact which can be electrically connected/disconnected with said second fixed contact, said first casing comprising a second porthole spaced apart from said first porthole for visually checking the position of said second movable contact.

7. The switchgear device according to claim 6, characterized in that each pole comprises a second earth contact for earth connection with said second movable contact, said second earth contact being positioned inside said first casing such that it is visible from outside the first casing through said second porthole.

8. The switchgear device according to claim 6, characterized in that said second porthole and said second terminal are positioned substantially opposite to each other with respect to said reference axis.

9. The switchgear device according to one or more of the previous claims characterized in that each pole comprises a third terminal and in that said disconnector unit comprises a third fixed contact operatively coupled to said third terminal and a corresponding third movable contact which can be electrically connected/disconnected with said third fixed contact, said first casing comprising a third porthole for visually checking the position of said third movable contact.

10. The switchgear device according to claim 9 characterized in that each pole comprises a third earth contact for earth connection with said third movable contact, said third earth contact being positioned inside said first casing such that it is visible from outside the first casing through said third porthole.

11. The switchgear device according to one or more of preceding claims, characterized in that said supporting structure comprises a plurality of members assembled to each other defining at least one surface for connection with said first casing.

12. The switchgear device according to one or more of preceding claims, characterized in that said supporting structure comprises at said base a bearing device having a substantially flat surface which extends transversally relative to said reference axis on which an end portion of said first casing rests, and a first member having a substantially flat surface close and extending perpendicular relative to said flat surface of the bearing device where said first casing is removably connected to.

13. The switchgear device according to claim 12, characterized in that said supporting structure comprises a second member which is spaced apart from said first profiled member and has a corresponding flat surface extending transversally with respect to said flat surface of the bearing device, and in that said first casing comprises an outward protrusion connected to said corresponding flat surface of the second profiled member.

14. The switchgear device according to claim 12, characterized in that said supporting structure comprises a hinge device which is fixed to said base and is operatively coupled to said bearing device so as to allow rotating said bearing device relative to the base.

15. The switchgear device according to one or more of the preceding claims characterized in that it comprises actuating means for operating the disconnector unit and the circuit breaker unit, and in that each pole comprises a second casing operatively coupled with said actuating means, which houses said interruption contacts and on the outer surface of which at least said first movable contact is mounted, said second casing being pivotally mounted inside said first casing so as to rotate said first movable contact during operation of said disconnector unit, said couple of interruption contacts being operatively coupled to said actuating means so as to be kept electrically coupled in said circuit breaker closed position and substantially still relative to each other during rotation of said second casing.

16. The switchgear device according to claim 15, characterized in that said couple of interruption contacts are operatively coupled to said actuating means so as to rotate, during rotation of the second casing, about said longitudinal reference axis substantially simultaneously to each other while being electrically coupled in said circuit breaker closed position, and to translate one relative to the other along said longitudinal reference axis during operation of said circuit breaker unit.

17. The switchgear device according to claim 15 characterized in that said couple of interruption contacts are operatively coupled to said actuating means so that, during rotation of the second casing, they are kept still with respect to the second casing itself and electrically coupled in said circuit breaker closed position, and to translate one relative to the other along said longitudinal reference axis during operation of said circuit breaker unit.

18. An electric power station suitable to be connected to a power line, characterized in that it comprises a power transformer and a gas-insulated switchgear device according to one or more of the preceding claims which is electrically connected to said power transformer and to said power line or to another electrical equipment.

19. The electric station according to claim 18 characterized in that each pole of said gas- insulated switchgear device has a first terminal connected to said transformer by means of a first bushing and a second terminal which is connected to said power line on to another electric equipment by means of a cable.

20. The electric station according to claim 18 characterized in that each pole of said gas- insulated switchgear device has a first terminal connected to said transformer by means of a first cable and a second terminal which is connected to said power line or to another electric equipment by means of a second cable.

21. The electric station according to claim 18 characterized in that said gas-insulated switchgear device is positioned at a distance from and with at least the first terminal of each pole facing the transformer, and in that a first protecting net and a second protecting net are positioned at the respective sides of and run from the gas-insulated switchgear device up to said transformer so as to laterally delimit an area inside which the electrical connections between each pole and the power transformer and each pole and said power line or said another electrical equipment are positioned.

22. The electric station according to claim 18 characterized in that said gas-insulated switchgear device is positioned inside a container.

23. A wind power generation station comprising at least one wind tower characterized in that it comprises a gas-insulated switchgear device according to one or more of the claims 1-17 which is positioned inside said tower.