SWITCHGEAR

DESCRIPTION

Technical Field

The invention discloses combined disconnecting-earthing switching module, with three working positions, used in a gas-insulated switchgear (GIS) . Therefore, the invention's technical field may be regarded as an improvement in gas/air break switches for high tension without arc-extinguishing or arc-preventing means; specifically used for disconnecting or earthing the system and enclosed in, or structurally associated with, metal casing such as GIS.

Technical Problem

Accordingly, one object of the invention is to provide an improved combined disconnecting-earthing switching module for a gas-insulated switchgear that is widely applicable, compact and reliable in operation due to the minimum amount of elements used to achieve the technical effect.

The first technical problem solved with the present invention is the construction of compact, combined disconnecting-earthing switching module where movement direction of contact pin and earthing pin forms the right angle, while having only three elements within the said module. These elements are: already mentioned contact pin and earthing pin; and specially constructed transmission means that engage and lock said pins in desired working positions. Considering the fact that the desired technical effect is produced without levers or gears within the module, it should be emphasised that the disclosed construction is gravity independent mechanism where the module functionality is flawless despite the module's spatial orientation. Last feature allows the mentioned module to have a wide range of implementation capabilities within already mounted GIS devices considering the fact that the geometrical scaling of the disclosed module is straightforward.

Second technical problem solved with the present invention is that the disclosed solution offers standard three working positions mechanism. First position, when contact pin is inserted into GIS fixed contact formed on its bus-conductor while the earthing pin is locked within the module disclosed in the invention. Second position, when contact pin and earthing pin are booth locked to the module disclosed by the invention. Third position, when contact pin is locked to the module disclosed by the invention while earthing pin is inserted into GIS earthing fixed contact.

Previous State of the Art

The importance of the electric distribution system increases demands for development of used equipment. Those trends are evident in the field of gas-insulated switchgear (GIS) and in developments of its parts. This is also true for improvements in switching devices regarding the three working positions module; especially the demands for the said module to be minimised - which is one of the technical problems solved with the invention. Such module should provide contact, earthing and neutral position for the high-voltage conductor apart from the main switching device, i.e. chamber, equipped with the arc-extinguishing or arc-preventing means.

Previous state of art is considerably reach. The review of the prior art begins with the class of solutions where contact pins are permanently connected to the driving mechanism via levers, rods or similar engaging elements.

Document EP 0735637 A2 "Switchgear having a grounded metal casing filled with insulating gas", inventors: Fuechsle D. et al . , discloses mechanism where the contact pins are engaged via levers. The contact pins in the embodiment, as disclosed on Fig. 8, are placed in the way that pin' s movement directions form sharp angle close to the right angle. The essential difference between the cited art and disclosed invention are lever operated pins, despite the fact that the solution offers three position mechanism.

Document WO 99/62154 Al "Encapsulation module with a combined disconnecting-earthing switch for a gas-insulated switchgear", inventors Damb.ietz H. P. et al., discloses combined disconnecting- earthing switches which are integrated in a conducting path inside an encapsulation module in gas-insulated switchgear, as is the case with disclosed invention. The switching elements are in the form of a linearly displaceable sliding contact pins with a contact area on the encapsulation side. Cited prior art is again lever operated, however the compactness is achieved by the innovative distribution of the operating elements.

Document WO 2010/149482 Al "High-voltage assembly", inventors Schulze- Wischeler D. et al., discloses the switching module with a gear having two coupling rods that can be pivoted in a predetermined pivot plane and that displace an associated electric contact element during pivoting in order to produce three working positions, which is also the case with present invention. Said prior art is rod/lever operated, however the compactness is achieved by the distribution of the operating elements. This solution is improved variant of previously cited document and the angle between the contacts is greater than the right angle.

Document US 8,487,203 disconnecting switch with earthing switch", inventors Shin T. et al., discloses the switching module with the function identical to the disclosed invention; the moving contacts are positioned at the right angle to achieve compactness, where said contact are engaged via curved links attached to the moving part i.e. transmission means. However, the disclosed invention is even more compact then the cited art, with considerably less elements used to achieve the same functionality. Document EP 2178099 Al ,,High- or medium-voltage electrical switching apparatus with two switches comprising driving means shared with the mobile contacts of the switches", inventor Treier L., discloses the switching module with the function identical to the disclosed invention; the moving contacts are positioned at the right angle to achieve compactness. Moving contacts are powered in a complex manner via curved links attached to the moving part that consists of levers hinged to one of movable contacts, and the engaging pins are engaged by one of cam grooves, as obvious from the corresponding figures. However, the disclosed invention is even more compact then the cited prior art, with considerably less elements used to achieve the same functionality.

Document WO 2015/003864 Al "High-voltage electric switching arrangement in a metal casing",, inventors Bournat-Querat F. et al.., discloses the switching module with two operating shafts in one embodiment, which is far more complex than the disclosed invention but illustrates recent trends in switching modules development.

Document WO 2013/002472 Al ,,3-way switch for a gas-insulated apparatus"; inventor Lee Chul-Ho, discloses the switching module with the function identical to the disclosed invention, moving contact are arranged again at the right angle. The cited prior art is far less compacts then the disclosed invention due to the space needed for the operating mechanism formed with the sliders and levers.

Another important class of technical solutions are solutions where the connecting pins or moving contacts are engaged by the coupling or decoupling mechanism.

Document US 6,400,244 „Control apparatus for electrical switchgear", inventors Bergamo D. et al . , discloses linear switching module . A three-position control apparatus has a control shaft secured to a Maltese cross provided with two drive slots and rotated from a determined angular position to an angular position from among two other determined angular positions in order to produce desired technical effect. Those solutions are not applicable to the GIS due to lack of compactness.

Document CN 201084615 „A three-station mechanism auxiliary switch driving device", inventor Minghou Liao discloses a three position switch where rotating shaft engages and disengages the engaging parts via engaging pins and levers. The disclosed system is far more complex than the disclosed invention and has different purpose, i.e. not to be mounted as the part of the GIS.

The cited prior art solutions and even their mutual combinations cannot straightforwardly reproduce the disclosed invention that has advantages mentioned in the section technical problem.

Summary of the Invention

The present invention discloses a combined disconnecting-earthing switching module for a gas-insulated switchgear. This module has casing which enclose contact pin and earthing pin and transmission means for operating said pins. Contact pin is used to electrically connect or disconnect said module with a bus conductor over the contact path. Earthing pin is used to electrically connect or disconnect said module with an earthing fixed contact over the earthing path. Bus conductor and earthing fixed contact belong to the GIS where said module is fixed via electrically conductive support.

Contact pin and earthing pin are slidable within the casing in the way that each contact pin slider and each earthing pin slider slides within the contact pin guide and earthing pin guide respectively. Pin guides are formed on the casing and sliders are formed on the corresponding pins. Transmission means is cylindrically shaped object and situated within the module. It is capable to rotate around the axis that is perpendicular to the plane in which pins slides. The transmission means has an operation shaft insertion place for providing external operation power to the module, smooth outer surface that is partially equipped with a nose having engaging pin for engaging or disengaging the movable pins.

The angle between the contact pin movement direction and the earthing pin movement direction is the right angle in order to minimise the module space consumption. Engaging pin is capable of engaging or disengaging one of said pins at the time via contact pin engaging slot or earthing pin engaging slot respectively that are formed on the contact pin engaging part or earthing pin engaging part. Transmission means and its engaging pin is rotating within the angle range [-90°, +90°] measured from the intersection point of said pins movement directions. Cylindrical outer surface is capable to locks one or both non-engaged pins via corresponding pin recessions in disconnecting position within the said module.

The disclosed module is forming three different working positions: first position, when contact pin is fully inserted into fixed contact of the GIS bus conductor and earthing pin is locked within the module with cylindrical outer surface that enters earthing pin recession;

second position, when contact pin and earthing pin are booth locked to the module with cylindrical outer surface that partially enters earthing pin recession and contact pin recession simultaneously; and

third position, when contact pin is locked to the module with cylindrical outer surface that enters contact pin recession and earthing pin is fully inserted into GIS earthing fixed contact.

In the preferred embodiment the contact pin guide and earthing pin guide are formed as a longitudinal slots machined on the casing. Also, the contact pin and the earthing pin are cylindrically shaped, except the contact pin engaging part and earthing pin engaging part. Contact pin and the earthing pin have contact pin recession and earthing pin recession with its curvature close to the radius of cylindrically shaped transmission means. Brief Description of the Drawings

Fig. 1 represents the combined disconnecting-earthing switching module for a gas-insulated switchgear, disclosed hereby, in the isometric view.

Fig. 2 represents the cross section of combined disconnecting-earthing switching module for a gas-insulated switchgear formed in a way to depict all the elements used within.

Fig. 3 shows one of the possible module working position within the gas-insulated switchgear; where contact path is closed and earthing path is open.

Figs. 4A, 4B, 4C, 4D and 4E shows contact and earthing pin positions, in respect with the angle produced by the transmission means; Fig 4Ά depicts the situation where contact path is closed and earthing path is open; Fig 4B depicts the situation where contact pin is retracted from the fixed contact and earthing path is still open; Fig 4C depicts the situation where contact path and earthing path are open, so-called neutral position; Fig 4D depicts the situation where contact path is open and the earthing pin is engaged but not connected to the earthing fixed contact; and finally, Fig 4E depicts the situation where contact path is open and earthing path is fully closed.

Figs. 5A and 5B show the module working position that corresponds to the situation already depicted on Figs. 4A and 4E, once module being inserted and fixed within the gas-insulated switchgear compartment.

Detailed Description

The invention discloses combined disconnecting-earthing switching module, with three working positions, used in a gas-insulated switchgear. As already mentioned, there is constant need for improvements in switching devices regarding the three working positions module to be minimised in its dimensions, which is one of the mentioned technical problems solved with the invention. Such module should provide contacting, earhing and neutral position for the high-voltage conductor apart from the main switching device, i.e. main switching chamber, equipped with the arc-extinguishing or arc- preventing means .

The preferred embodiment will be described in more detail having in mind that the prior art, as we have demonstrated before, contains a lots of technical solution producing the same effect but dominantly using levers or rods which complicate the switching module design.

Fig. 1 represents the combined disconnecting-earthing switching module (10) for a gas-insulated switchgear in isometric view. The module (10) has a casing (11) that is formed from a metal or an alloy having excellent electrical conductivity properties, good mechanical properties; that is durable, lightweight, has good machinability and ability to be easily casted or mold into desired shapes. Such materials are already in use in the art, not only for the casing (11) but also for other elements. Other main components of the module (10) are: contact pin (30) , earhing pin (40) and transmission means (20) situated within the casing (11) . As in the case of the casing (11) , the similar requirements are used for the material selection for contact pin (30) and earhing pin (40) ; while the transmission means (20) can be manufactured even from the material having rather poor electrical conductivity properties.

Fig. 2 discloses the cross section of the module (10) ; casing (11) is formed as the stylised right angle triangle, with equally length catheti; where movement directions of the pins (30, 40) are parallel to said catheti. Casing (11) is equipped with one or more pin insertion places (12) that enable correct positioning of the said casing (11) relative to the conductive support (60) once conductive pins (62) are inserted. Screw fixation hole (13) enables fixation of the module (10) within the GIS, more particular to the lower part of conductive support (60) via appropriate screw. Intersection of the catheti and hypotenuse forms contact pin passage (14) and earthing pin passage (15) that enables said pins (30, 40) to be retracted into the module (10) and to be again pulled out of the module (10) sufficiently to bridge the contacting path (39) and earthing path (49) shown on Fig 3.

Contact pin (30) and earthing pin (40) are formed essentially as the solid cylinder, but other geometries are also possible. Contact pin (30) has, on one of its bases formed a contact pin groove (31) and on the opposite base a contact pin engaging part (33) . Said contact pin engaging part (33) has the geometry that is not cylindrical but rather cuboid shaped, with the machined contact pin engaging slot (34). The other earthin pin (40) is formed in the same way, having earthing pin engaging part (43) with the earthing pin engaging slot (44) on one side and with the earthing pin groove (41) formed on another earthing pin (40) base. In real operation the pins (30, 40) are identical, but other variants are also possible, so the skilled person in the art will certainly recognise them.

Contact pin (30) has one or more contact pin sliders (35) formed on its surface. Earthing pin (40) has one or more earthing pin sliders (45) formed on its surface. Contact pin sliders (35) are designed to be compatible with the contact pin guides (16) formed on the casing (11) and earthing pin sliders (45) are designed to be compatible with the earthing pin guides (17) also formed on the casing (11); see Fig. 1. Pin guides (16, 17) define the movement direction of corresponding pins (30, 40) . In the preferred embodiment pin guides (16, 17) are manufactured as the slots machined in the casing (11) .

Contact pin (30) has machined contact pin recession (32) on its longitudinal outer surface and the earthing pin (40) has machined earthing pin recession (42) on its longitudinal outer surface as depicted on the Fig. 2. Said pin recessions (32, 42) is used to lock the said pins (30, 40) via transmission means (20), more particularly by the outer surface (24) of said transmission means (20) , by the casing (11) . Transmission means (20) is formed as the rather short hollow cylindrical object which interior is dedicated to be operating shaft insertion place (23) . Operating shaft, that is not depicted, is used to give the operational power for using said module (10) once said shaft is inserted into the place (23) . Part of the transmission means (20), i.e. part of the outer surface (24) is deformed into the elongated nose (21) with engaging pin (22). The engaging pin (22) dimensions are designed to smoothly enter and engage contact pin engaging slot (34) or earthing pin engaging slot (44) of the corresponding pins (30, 40) .

The transmission means (20) and its engaging pin (22) are free to rotate, by using the outer force, within the angle range [-90°, +90°] measured from the intersection point of said pins (30, 40) movement directions that falls on the catheti intersection. Rotation of the transmission means (20) engages or disengages the pins (30, 40) , retract and pull out said pins (30, 40) from the casing (11) and lock the pins (30, 40) to the said casing (11) . Movement of transmission means (20) produce three working positions that we will discuss later.

Fig. 3 shows position of the module (10) within the compartment walls (50) of the said GIS. Module (10), i.e. its casing (11), is fixed to the conductive support (60) via one or more conductive screw (61) inserted from the casing (11) interior and one or more conductive pins (62) are disposed into pin insertion places (12) machined in the casing (11) . Conductive pins (62) secure the relative position of the module (10) to the conductive support (60).

Conductive pin (30) is designed to bridge the contact path (39) and to be inserted into fixed contact formed on bus conductor (70) once it's pulled out from the casing (11) by the action of the transmission means (20) . In the art it is common to observe said bus conductor (70) connected with the bus connector (71), as depicted on the Fig. 2. Similarly, earthing pin (40) is designed to bridge the earthing path (49) and to be inserted into earthing fixed contact (90) . Said earthing contact (90) is attached to the earhing fixed conducting holder (91) once said earthing pin (40) is pulled out from the casing (11) by the action of the transmission means (20) . The working procedure of the said module (10) is depicted via series of Figs. 4A-4E, that we will be inspected shortly in more details. The initial situation is depicted in the Fig. 4A that corresponds to the situation depicted on the Fig. 5A. Transmission means (20) is in the position close to the angle -90°; contacting pin (30) is fully inserted into the fixed contact (80) establishing therefore the electric contact between the bus conductor (70) via module (10) to the conductive support (60) . Outer surface (24) of the transmission means (20) is nested into the earthing pin recession (42) on the earthing pin (40) and locks the said pin (40) to the module (10).

Now, the transmission means (20) starts to rotate clockwise from the angle close to -90°. The engaging pin (22) situated within the contacting pin engaging slot (34) retracts the connecting pin (30) form the fixed contact (80) and is continuously acting to the contact pin engaging part (33) . Earthing pin (40) is still locked to the casing (11) as visible on the Fig. 4B.

The situation on the Fig. 4C shows the situation when transmission means (20) is in the position close to the angle 0°; engaging pin (22) is situated between the contacting pin engaging slot (34) and earthing pin engaging slot (44); earthing pin (40) and connecting pin (30) are both locked to the casing (11) via outer surface (24) of the transmission means (20) that partially engages contact pin recession (32) and the earthing pin recession (42) . This is the neutral position of the module (10) where the conductive support (60) is not connected to the bus connector (70) nor to the earting fixed contact (90) .

Further clockwise rotation of the transmission means (20) , Fig. 4D, locks entirely contacting pin (30) to the casing (11) via outer surface (24) that engages contact pin recession (32) . The engaging pin (22) is now pulling the earthing pin engaging part (43) and therefore the corresponding earthing pin (40) out of the casing (11) . Finally, when transmission means (20) is in the position close to the angle +90°; the earthing pin (40) is pulled out maximally. That situation is depicted on the Fig. 4E; the earthing pin (40) completely bridges the earthing path (49) and is inserted fully into earthing fixed contact (90) . That corresponds to the situation presented on the Fig. 5B; the electric contact is established between the conductive support (60) and the earthing fixed conducting hdlder (91) via said earthing fixed contact (90) .

When transmission means (20) rotates counter clockwise from the position depicted on Fig. 4E to that depicted on the Fig. 4A, the sequence of the module (10) states are repeated in the opposite manner. Also, it should be noted that the pin recession (32) and earthing pin recession (42) respectively have the curvature close to the radius of cylindrically shaped transmission means (20) .

Few words should be addressed to the pins (30, 40) ends and their contacts established with the fixed contact (80) and earthing fixed contact (90) respectively. It is known in that art that fixed contacts (80, 90) as well as the portion of the casing (11) close to the contact pin passage (14) and earthing pin passage (15) is equipped with the conducting springs that secures electrically and mechanically connections of the said pins (30, 40) to the casing (11) and to the corresponding fixed contacts (80, 90) . Moreover, fixed contact bulge (81) is the result of screw fixation of the fixed contact (80) to the bus conductor (70), as is common in the art. So, the contact pin groove (31) is designed to enclose said contact bulge (81) . Considering the fact that the preferred embodiments use equaly machined pins (30, 40) , the earthing pin groove (41) has no further technical meaning. Namely, the contact pin (40) passes entirely through the earthing fixed contact (90) . In the preferred embodiment, earthing fixed contact (90) is made as hollow cylinder connected to the earthing fixed contact holder and equipped with the conducting springs that secure electrical and mechanical connections with the erathing pin (40) . Other variants are also possible, for instance it is possible to form the earthing fixed contact (90) in the manner used for the fixed contact (80) and then the earthing pin groove (41) will have a technical sense. Considering the above said, it is obvious that the disclosed solution is very easy to implement on various places within the GIS where contact pins movement directions are positioned at the right angle for the compactness. In addition, the skilled person in the art will certainly recognise the potential of the disclosed module (10) mechanism and form necessary trivial modification or adjustments for some other usages within the GIS.

Industrial Applicability

Industrial applicability of the said invention is obvious. The present invention discloses an improved combined disconnecting-earthing switching module for a GIS that has three different working positions where the desired technical solution is obtained via direct acting of the transmission means to the contact pin and earthing pin respectively. The present invention is more compact and much simpler than the solutions found in the previous art, as we demonstrated hereby.

References

10 Module

11 Casing

12 Pin insertion place

13 Screw fixation hole

14 Contact pin passage

15 Earthing pin passage

16 Contact pin guide

17 Earthing pin guide

20 Transmission means

21 Nose

22 Engaging pin

23 Operating shaft insertion place

24 Outer surface

30 Contact pin

31 Contact pin groove Contact pin recession

Contact pin engaging part

Contact pin engaging slot

Contact pin slider

Contact path

Earthing pin

Earthing pin groove

Earthing pin recession

Earthing pin engaging part Earthing pin engaging slot Earthing pin slider

Earthing path

Compartment wall

Conductive support

Conductive screw

Conductive pin

Bus conductor

Bus connector

Fixed contact

Fixed contact bulge

Earthing fixed contact

Earthing fixed conducting holder