EP4738409A1

EP4738409A1 - Switchgear, method and use

Info

Publication number: EP4738409A1
Application number: EP24210162.4A
Authority: EP
Inventors: Markus Richter; Uwe Riechert; Hans-Dieter SCHLEMPER
Original assignee: Hitachi Energy Ltd
Current assignee: Hitachi Energy Ltd
Priority date: 2024-10-31
Filing date: 2024-10-31
Publication date: 2026-05-06

Abstract

The invention relates to a switchgear (1) for breaking an electrical connection, comprising
a first contact structure (10) with a first base (12) and a first contact member (14);
a second contact structure (20) with a second base (22) and a second contact member (24) and corresponding to the first contact structure (10);
a spring accumulator (30) configured for resiliently mounting the first (14) or the second (24) contact member on the respective first (12) or second (22) base;
a drive system (40) configured for at least partially moving the first (14) and the second (24) contact members relative to one another along a switching axis (2) in order to break the electrical connection to ground (GND); and
a locking means (50) configured for locking the first (14) and the second (24) contact members along the switching axis (2) in a releasable manner.

Description

Technical Field

The invention relates to a switchgear, the switchgear comprising contact members and a locking means configured for locking the contact members in a releasable manner. The invention further relates to a method and to a use.

Background Art

Switchgears remain an area of interest. Some existing switchgears have various shortcomings, drawbacks, and disadvantages relative to certain applications. For example, in some switchgears, improvements in their construction and/or electrical properties for a better reliability may be made. In addition, costs need to be optimized. Accordingly, there remains a need for further contributions in this area of technology.

Summary of invention

It is therefore an object of the invention to provide solutions with respect to switchgears that provide an enhanced maintenance, reduced cost, and increased lifetime. It is another object to widen the field of application of switchgears. Particularly it is an object to avoid or reduce disadvantages of known solutions.
The object of the invention is solved by the features of the independent claims. Preferred implementations are detailed in the dependent claims, the description, and the figures.
The object is particularly solved by a switchgear for breaking and optionally making an electrical connection, the switchgear comprising

a first contact structure with a first base and a first contact member;
a second contact structure with a second base and a second contact member and corresponding to the first contact structure;
a spring accumulator configured for resiliently mounting the first or the second contact member on the respective first or second base;
a drive system configured for at least partially moving the first contact member and the second contact member relative to one another along a switching axis in order to break and optionally make the electrical connection to ground; and
a locking means configured for locking the first and the second contact members along the switching axis in a releasable manner.

In other words, particularly, a contact system with a snapping mechanism is used to disconnect an electrical system substantially automatically and rapidly from a connection to ground. Thus, a crucial advance is seen in that a disconnector or disconnector contact system is used in order to break an electrical connection to ground.
The invention realizes that induced switching ratings can be cleared efficiently. The spring accumulator realizes that the time of presence of an arc may be minimized, particularly thereby wear of the switchgear may be reduced as well.
The effects and advantages named herein may be improved further by adoption of preferred features or a combination thereof.
The switchgear is preferably configured for medium and/or high voltage switching applications. The switchgear may be capable of switching currents of 100 A or 160 A or more particularly at high voltages of 72.5 kV, particularly up to 1200 kV. The term medium voltage may refer to a voltage from 1 kV to 72.5 kV, and the term high voltage to a voltage greater than 72.5 kV. The term high voltage means preferably a voltage above 12 kV or 36 kV or 72 kV or 1100 kV. A high voltage preferably relates to nominal voltages in the range from above 12 kV, 36 kV or 72 kV to 550 kV or 1100 kV, like 145 kV, 245 kV or 420 kV, or more. The term medium voltage means preferably a voltage above 1 kV or 12 kV or 36 kV. A medium voltage preferably relates to nominal voltages in the range from above 1 kV, 12 kV or 36 kV to 72 kV, like 5 kV, 10 kV, 25 kV or 70 kV.
The switchgear may have two contacts or more than two contacts, i.e. at least two contacts.
The switchgear is particularly configured for breaking an electrical connection. The switchgear is particularly configured for making the electrical connection. Typically, the electrical connection is at least between the two contact members, wherein one of the contact members can be connected to ground. As such, breaking the electrical connection typically relates to disconnecting one of the contacts from ground, which contact to be disconnected from ground may be further connected to an electrical system of which induced current ratings can be cleared by said disconnecting/breaking. Optionally the switchgear can withstand fast acting earthing switch making requirements.
The switchgear may be a gas-insulated high-voltage switchgear (GIS) and, in particular, an on-load earthing switch having a movable first contact structure and a stationary or movable second contact structure.
The first contact structure has a first base and a first contact member. The second contact structure has a second base and a second contact member. The second contact structure corresponds to the first contact structure. For example, the contact structures or members correspond in shape to one another in order to provide an efficient electrical connection by being in contact to one another in terms of area. The bases may be arranged at a fixed distance to one another and/or in a fixed arrangement, wherein the contact members may be arranged movable relative to one another. For example, one or both contact members may be movable in its respective base, particularly at least substantially along an axis and/or a straight line. A base may include a housing or a substantially rigid structure and may be at least partially hollow in order to accommodate a contact member. Bases and contact members may be made from (a) metal alloy(s) in order to conduct electricity.
The spring accumulator is configured for resiliently mounting the first contact member or the second contact member on the respective first base or second base.
The spring accumulator may not necessarily include a spring in a literal sense, but may include elastic means or parts. The spring accumulator may include an elastically deformable part, such as a spring. The spring accumulator typically is configured to resiliently store energy, e.g. in a fluid or in a mechanical mechanism. Particularly, the spring accumulator may be allocated to one of the two contact structures. For example, the spring accumulator may be integrated in one of the contact structures and interacting between the respective base and contact member. The spring accumulator may be configured to push back the contact member to a first position when it has been deflected. For example, the spring accumulator may resiliently store energy, e.g. elastic energy, when the respective contact member is moved or deflected. The spring accumulator may ensure that the respective contact member automatically moves back to its original position when deflected, e.g. in order to speed up a breaking procedure when contact members are separated from one another.
The drive system is configured for at least partially moving the first contact member and the second contact member relative to one another along the switching axis in order to break and optionally make the electrical connection to ground. For example, the drive system includes a spindle mechanism with a spindle and a spindle nut, the spindle nut carrying one of the contact members. It may be that the drive system can bring the contact members out of contact for breaking and optionally can bring them into contact with one another for making. The drive system can include a motor or the like configured to move the respective contact member, e.g. by means of the spindle mechanism.
Optionally, a making capability may be covered by another independent or integrated switchgear. Thus, an arrangement of at least two switchgears may be provided, one of the two switchgears being the one described herein and the other one of the two switchgears configured for making an/the electrical connection. Said two switchgears may be connected to one another, e.g. parallelly or serially.
The switchgear has the locking means, wherein the locking means is configured for locking the first contact member and the second contact member in a releasable manner, particularly along the switching axis and/or about the switching axis. For example, the locking means or locking device provides a form fit and/or force fit acting between the two contact members. The form fit or force fit may be undone by enough force, e.g. pulling the two contact members away from one another. For form fit or force fit may be provided by getting the two contact members in touch with one another. The locking means may substantially provide a latching principle or arrest principle or snapping principle. The locking means can provide that the electrical connection is safely held, e.g. against a force built up in the spring accumulator which force pulls one contact member away from the other contact member. The locking means may include at least one magnet.
The first contact member may be movably held in the first base. The first contact member may be coupled to the drive system. For example, the first contact member may be guided by means of a guide relative to the first base. The first contact member may be movable between a retracted position and an extended position. In the retracted position, the first contact member may be arranged at a first distance relative to the second base, while in the extended position the first contact member may be arranged at a second distance relative to the base, the first distance being larger than the second distance. The second distance may be substantially zero, e.g. in case of electrical contact. The drive system may be configured to move the first contact member between the retracted position and the extended position. The first contact member may be coupled to a spindle nut to be moved by means of a spindle of the drive system, e.g. along said guide.
The second contact member may be movably held in the second base. The second contact member may be resiliently mounted, especially via or by means of the spring accumulator, on, particularly in, the second base. For example, the second contact member may be guided by means of a guide relative to the second base. The second contact member may be movable between a retracted position or first position and an extended or second position. In the retracted position, the second contact member may be arranged at first another distance relative to the first base, while in the extended position the second contact member may be arranged at a second another distance relative to the first base, the first another distance being larger than the second another distance. The second another distance may typically not reach zero and/or the second contact member may not get into contact with the first base. Optionally, the drive system may be configured to move the second contact member between the retracted position and the extended position. The second contact member may be coupled to a spindle nut to be moved by means of a spindle of the drive system, e.g. along said guide.
The first contact member and the second contact member may be configured for mating with one another, e.g. to provide contact in terms of area. The first contact member may be configured for mating on an inside or outside of the first contact member with the second contact member on an inside or outside of the second contact member. The first contact member may comprise a tube shape and/or an axially elongated shape, e.g. with a substantially round cross section. The second contact member may comprise an axially elongated shape, e.g. with a substantially round cross section, and/or optionally a tube shape. The second contact member, particularly the axially elongated shape, may be configured for mating on the outside or inside of the second contact member, particularly the axially elongated shape, with the inside or outside of the tube shape. One contact member may thus surround the other contact member in order to establish and electrically conductive path at relatively low contact resistance.
The second base may comprise a receptacle, for example with an opening, e.g. a substantially round opening or with a protrusion, e.g. a substantially round protrusion. The receptacle may correspond to the first contact member. The second base, particularly the receptacle, may be configured for mating on an inside or outside of the second base, particularly on an inside or outside of the receptacle of the second base, with an outside or inside of the tube shape of the first contact member, particularly in order to conduct a switching current of at least 160 A, e.g. when the first contact member is in the extended position A/the switching current may be conducted through the first base, through the first contact member, and through the second base; optionally, not necessarily, the switching current may be conducted through the second contact member. It may be realized that the first contact member can directly contact the second base and/or the second contact member, particularly both, especially when in the extended position. The second contact member may be arranged to extend out of or through or around the receptacle of the second base, especially forming a gap for the first contact member.
The second contact structure may comprises a guide for guiding the second contact member, e.g. between a first position or retracted position and a second position or extended position along the switching axis. The guide may include a, particularly substantially cylindrical, rod on or along which the second contact member is guided. The rod may extend through or along the second contact member.
The spring accumulator may have a spiral spring or torsion spring. The spring accumulator may act along and/or about the switching axis and/or between the second contact member and the guide. For example, the spring accumulator may be arranged on the guide in order to interact with the second contact member. The spring accumulator may be arranged inside the second contact member. The spring accumulator may be configured to be charged upon moving the second contact member from the first position towards the second position of the second contact member. For example, the spiral spring may be configured to be compressed or extended upon moving the second contact member away from its first position and/or towards an/the extended position.
The locking means may include a metallic tulip and a metallic ring. The ring may be arranged on the first contact, e.g. on a front of the first contact member, particularly facing the second contact structure. The ring may be configured for interacting with the tulip, e.g. in order to realize an electrical connection, a form fit and/or a force with one another. The ring may be configured to surround the second contact member when the contact members are contacting one another. The tulip may be arranged on the second contact member, particularly on a circumference of the second contact member and/or on a front of the second contact member, the front especially facing the first contact member. For example, the tulip includes one or more spring elements to be compressed by the ring, e.g. in order to realize a releasable form fit and/or force fit acting along the switching axis. The spring elements may be distributed about the circumference of the second contact member and/or about the switching axis. The tulip may be attached to the second contact member, e.g. pressed or screwed thereon. The ring may be attached to the first contact member, e.g. pressed or screwed thereon.
The metallic ring and/or the metallic tulip may include tungsten and/or copper, particularly an alloy therewith. Alternatively or additionally, steel may be used, particularly for the metallic tulip.
The first contact member may be provided with an arcing element. The arcing element may include tungsten and/or copper, particularly an alloy therewith. The arcing element may be provided on the side of the first contact facing the second contact structure, particularly facing the second contact member or an arcing element thereof.
The second contact member may be provided with an/the arcing element. The arcing element may include tungsten and/or copper, particularly an alloy therewith. The arcing element may be provided on the side of the second contact facing the first contact structure, particularly facing the first contact member. The arcing element or the metallic ring or both may face an arc when the contact members are disconnected or connected. For example, an arc may extend temporarily between the metallic ring and the arcing element.
The choice of material depends on the requirements related to wear, cost, contact resistance, weight and the like. Preferably, tungsten/copper is used when materials directly face arcs.
The second contact member and the guide may each comprise a stop element. The stop elements may be configured for stopping against each other, particularly in the second position. Said stopping may be provided in order to prevent further movement of the second contact member and especially to enable that the locking means can be released when the second contact is pulled/pushed further with the stop elements stopping against each other.
A damping element may be provided. The damping element may interact with the second contact member and particularly with the stop elements, e.g. in order to reduce mechanical loads and enhance fatigue. The damping element may include an elastic material, e.g. including a polymer compound or rubber or the like. The damping element may alternatively or additionally include a damper, the damper for example being a gas-based damper or liquid-based damper or mechanical friction based damper. The damping element may be integrated in a stopping element or embody a stopping element.
The switchgear may comprise an enclosure, the enclosure particularly configured to be filled with insulating gas or quenching gas. The insulating gas may include at least one of SF6 gas, N2 gas and CO2 gas. The enclosure may surround the contact structures, the spring accumulator and the locking means. The enclosure may surround the drive system at least in part, for example a spindle thereof. The enclosure may include a passage for the drive system, for parts of the drive system to be located on an outside and parts of the drive system to be located on an inside of the enclosure. The passage may enable a mechanical interaction between said parts. The enclosure may be configured gas tight to encapsulate the gas substantially leak-free and to provide arc suppression by choice of respective gas. The enclosure may furthermore include electrical passages in order to electrically connect the contact structures to ground (an/the) electrical system(s).
The switchgear may comprise a device configured for disconnecting the switchgear from ground in order to conduct measurements on electrical properties of the switchgear. For example, the device may include an accessory that, when removed or manipulated, can undo a connection of the switchgear, particularly the second contact structure, to ground. The device, e.g. the removable accessory, may be configured for manual removal. The device may ensure that the switchgear can be tested electrically once in a while to ensure proper function.
The switchgear may include one or more of certain electrical ratings, e.g. grounding voltage, switching current, and recovery voltage. The switchgear may be configured for grounding a voltage of at least 245 kV. The switchgear may be rated with a/the switching current of at least 160 A. The switchgear may be rated with a recovery voltage of at least 10 kV. The switchgear may be rated with a number of operations of at least ten, particularly considering an operation with/under a respective electrical load, e.g. involving respective current and voltage applied to the contacts. Such values may be achieved by sizing conductive parts, e.g. the contact structures, large enough, by choice of low-resistance materials like aluminum or copper based materials and by proper electrical insulation. Additionally, choice and hardness or respective hardening of materials can provide wear resistance to realize enough number of operations.
At least one of the first base and the second base may comprise or substantially consist of a cast part, particularly a cast aluminum part. Compared to steel, aluminum or alloys therewith have a good electrical conductivity, resistance to corrosion and are relatively light. Compared to copper, aluminum or alloys therewith comprise lower costs and are relatively light. For example, the first base and/or the second base may be cast parts in order to provide substantially hollow parts at low production costs.
The object can additionally be solved by means of a method to operate a switchgear, e.g. the switchgear as described herein. The method may include connecting the second contact structure to ground. The method may also include connecting the first contact structure to an electrical system, e.g. so that a ground connection of the electrical system can be disconnected or interrupted. The steps of the method may be conducted in the named order or in any other order.
The method may include breaking an electrical connection between (the) contact structures. The method may include moving or displacing the first contact member along the switching axis away from the second base for the spring accumulator to get charged while the first contact member and the second contact member are locked along the switching axis in a releasable manner, wherein the locking means releases, particularly upon sufficient build-up of force or charge in the spring accumulator and/or upon stopping elements stopping against each other, so that the spring accumulator moves, particularly resiliently, the first contact member and the second contact member away from one another.
The method may include making an electrical connection between (the) contact structures. The method may include moving the first contact member along the switching axis towards the second base for the first contact structure and the second contact structure to form an electrical connection and thereby the first contact structure to be connected to ground and the first and the second contact members to be locked along the switching axis in a releasable manner.
Furthermore, a use of a switchgear or the switchgear as named herein is suggested, particularly to break an electrical connection of an electrical system to ground, optionally, afterwards or before breaking, to make the electrical connection to ground.
The enumeration 'first' or 'second' shall primarily be understood as a nomenclature. This nomenclature may be interchanged in that features actually attributed to - for example - the 'first contact structure' might be alternatively or additionally attributed to the 'second contact structure'. In other words, features depending on the nomenclature 'first' and 'second' might be swapped or renamed.
The term 'or' may be replaced by 'and/or' throughout the present disclosure. As such, where 'or' is used, it is not necessarily meant that merely alternatives are named.

Brief description of drawings

These and other aspects of the invention will be apparent from and elucidated with reference to the implementations described hereinafter.
In the drawings:
Fig. 1A-G shows a switchgear for breaking an electrical connection to ground.

Description of implementations

The description contains procedural or methodical aspects upon describing structural features of the invention; the structural features can be understood well in that way. It is emphasized to the reader that such structural features can be lifted from the described context without hesitation or the question of an intermediate generalization to form aspects of the invention. It is also emphasized to the reader that any the structural features described in the following can be understood as individual aspects of the invention to distinguish from known solutions, despite being possibly lifted from the context.
Fig. 1A-G illustrates a making and a breaking operation of a switchgear 1, the switchgear 1 configured as a gas-insulated high-voltage switchgear (GIS), particularly an earthing switch. The figures differ from each other in that the components or parts are arranged differently. However, the same switchgear 1 is shown in all figures and thus similar reference signs apply.
The switchgear 1 comprises a first contact structure 10, a second contact structure 20, a spring accumulator 30, a drive system 40, and a locking means 50.
The first contact structure 10 has a first base 12 and a first contact member 14 that is movably held in the first base 12 and coupled to the drive system 40. The first contact member 14 can be moved or driven by means of the drive system 40 along a switching axis 2.
The first base 12 has a receptacle 18 in the form of an opening, particularly a substantially round opening. Especially when being moved, the first contact member 14 can extend through the receptacle 18. The first contact member 14 can be electrically contacted to the first base 12 especially via the receptacle 18, e.g. a contact means or sliding contact mounted therein.
The second contact structure 20 corresponds to the first contact structure 10 and has a second base 22 and a second contact member 24. The second contact member 24 is movably held in the second base 22 and resiliently mounted via the spring accumulator 30 on the second base 22. The second contact member 24 can be moved along the switching axis 2.
The second contact structure 20 is configured to be connected or is connected to ground GND, e.g. directly or via an enclosure 3 of the switchgear 1.
In Fig. 1A, both contact members 14, 24 are shown in retracted positions, particularly being disconnected from one another.
The first contact member 14 comprises a tube shape and the second contact member 24 comprises an axially elongated shape for mating on an outside of the axially elongated shape with an inside of the tube shape.
The first contact structure 10 comprises a guide 16 for guiding the first contact member 14 between a retracted position, cf. Fig. 1A, and an extended position, cf. Figs. 1B-G.
The first contact member 14 is connected to a spindle nut to be moved by a spindle of the drive system 40 along the switching axis 2. The spindle can rotate about the switching axis 2 as indicated in Fig. 1A.
The second base 22 comprises a receptacle 28 with an opening for mating on an inside of the receptacle 28 with an outside of the tube shape of the first contact member 14 in order to conduct a switching current of at least 10 A, particularly at least 100 A or 160A.
The opening of the receptacle 28 is substantially round.
Especially when in the extended position, the first contact member 14 can extend into or through the opening of the receptacle 28. The first contact member 14 can be electrically contacted to the second base 22 especially via the receptacle 28, e.g. a contact means or sliding contact mounted therein, cf. Fig. 1C.
The second contact structure 20 comprises a guide 26 in the form of a cylindrical rod for guiding the second contact member 24 between a first position or retracted position, cf. Fig. 1A, and a second position or extended position, cf. Figs. 1D-G, along the switching axis 2.
The spring accumulator 30 is configured for resiliently mounting the second 24 contact member on the second base 22. The spring accumulator 30 has a spiral spring and acts along the switching axis 2 and between the second contact member 24 and the guide 26.
The drive system 40 is configured for at least partially moving the first contact member 14 and the second contact member 24 relative to one another along a switching axis 2 in order to make or break the electrical connection of the first contact structure 10 to ground GND.
The locking means 50 is configured for locking the first contact member 14 and the second contact member 24 along the switching axis 2 in a releasable manner.
The locking means 50 includes a metallic tulip 52 and a metallic ring 54. The ring 54 is arranged on a front of the first contact member 14 facing the second contact structure 20 and is configured for interacting with the tulip 52. The tulip 52 is arranged on a circumference of the second contact member 24.
The tulip 52 includes spring elements to be compressed by the ring 54 in order to realize a releasable form fit and/or force fit acting or effective along the switching axis 2, cf. Fig. 1C-F.
The ring 52 is made of a metal alloy with at least 10 wt% (i.e. ten weight percent) tungsten and/or at least 10 wt% copper.
The second contact member 24 is provided on the side facing the first contact structure 10 with an arcing element 29 that is made of a metal alloy with at least 10 wt% tungsten and/or at least 10 wt% copper. The first contact member 14 is provided with an arcing element as well.
The second contact member 24 and the guide 26 each comprise a stop element 25. The stop elements 25 can stop against each other in the second position of the second contact member 24 so that the second contact member 24 cannot move further towards the first contact structure 10. Additionally, the second contact structure 20 is equipped with a damping element interacting with the second contact member 24 and the stop elements 25 or one of the stop elements 25, particularly in the second position. For example, the stop elements 25 may each be formed integrated with a damping element.
The switchgear 1 comprises the enclosure 3 that is substantially gas tight and filled with insulating gas, particularly SF6 gas, N2 gas and/or CO2 gas. The enclosure 3 might be a metallic and/or cast part.
The enclosure 3 typically is connected to ground GND.
The switchgear 1 comprises, particularly on the side of the second contact structure 20, a device 60 configured for particularly manually disconnecting the switchgear 1 from ground GND in order to conduct measurements on electrical properties of the switchgear 1, e.g. by hand. Typically, the device 60 is configured to connect the switchgear 1 to ground GND all the time.
The first base 12 is attached to the enclosure 3, e.g. screwed thereon, particularly in an electrically insulating manner, e.g. using electrically insulating structural parts between first base 12 and enclosure 3.
An electrical system 100 may be connected to the first contact structure 10, e.g. to the first base 12 and/or first contact member 14.
The switchgear 1 can be used to break the electrical connection of an/the electrical system 100 to ground GND. Alternatively or additionally, the switchgear 1 can be used to make the electrical connection of the electrical system 100 to ground GND. Making capability may as well be provided by a switchgear not shown in detail.
The second base 22 is attached to the enclosure 3, e.g. screwed thereon, particularly in an electrically conducting manner, for example with the device 60 in between.
The second base 22 comprises a cast aluminum part forming the receptacle 28 and substantially surrounding the second contact member 24. The second base 22 is hollow or in the shape of a bulb.
The switchgear 1 is configured for grounding a voltage of at least 245 kV, is rated with the switching current of at least 160 A, is rated with a recovery voltage of at least 10 kV, and is rated with a number of operations of at least ten particularly with electrical load.
Shown and described is a switchgear 1 with which a method can be conducted.
The method to operate the switchgear 1 may comprise, for example as a first step, connecting the second contact structure 20 to ground GND.
The method to operate the switchgear 1 may comprise moving the first contact member 14 along the switching axis 2 towards the second base 22. This is shown in Figs. 1A-C, where the first contact member 14 is being moved out of the retracted position of Fig. 1A towards the extended position of Fig. 1C.
Upon reaching the extended position, the first contact structure 10 and second contact structure 20 form an electrical connection and thereby the first contact structure 10 is connected to ground GND and the first contact member 14 and the second contact member 24 are locked along the switching axis 2 in a releasable manner. This is shown in Fig. 1C, where the electrical connection is formed for the first time and the contact members 14, 24 are locked in a releasable manner with each other.
In Fig. 1C, an electrical current may flow through the first base 12, the first contact member 14, and through the second base 24. This is illustrated by three arrows in Fig. 1C. Optionally, but not necessarily, current may flow through the second contact member 24.
The method to operate the switchgear 1 may comprise moving the first contact member 14 along the switching axis 2 away from the second base 22. This is shown in Figs. 1D-G, where the first contact member 14 is being moved out of the extended position of Fig. 1C via the positions as shown in Figs. 1D-G back towards the retracted position as already shown in Fig. 1A.
During moving the first contact member 14 away from the second base 22, the spring accumulator 30 gets charged while the first 14 and the second 24 contact members are locked along the switching axis 2 in a releasable manner. This results in that the second contact member 24 is pulled out towards an extended position and against the force of the spring accumulator 30, while the electrical connection is still upheld, cf. Figs. 3D-F. It is noted that an electrical current now does not flow anymore from the first contact member 14 to the second base 22, but from the first contact member 14 to the second contact member 24 and thereby to ground GND.
When the stopping elements 25 stop against each other, cf. the arrow pointing on the stopping elements 25 in Fig. 1F, the locking means 50 releases so that the spring accumulator 30 resiliently moves the second contact member 24 away from the first contact member 14, e.g. for the second contact member 24 to reach its retracted or first position.
As shown in Fig. 1G, where the contact members 14, 24 have just been disconnected and unlocked from each other, an arc A may form between said contact members 14, 24. For example, the arc A may extend between the ring 52 and the arcing element 29 and/or between the ring 52 and the tulip 52.
Additionally, the drive system 40 can move back the first contact member 14 in its retracted position as shown in Fig. 1A.
Describing the function of the procedures of operation of the switchgear 1 in other words, the first contact member 14 can mate with the second base 22 and with the second contact 24 member substantially simultaneously when being moved into the extended position of the first contact member 14, thereby establishing direct electrical contacts with both second base 22 and second contact member 24 (cf. Figs. 1A-C). This particularly relates to a making capability.
Upon moving the first contact member 14 back from the extended position towards its retracted position, the second contact member 24 can be pulled out of the second base 22 due to being locked with the first contact member 14 (cf. Figs. 1C-F).
When the second contact member 24 is being pulled out, the spring accumulator 30 may be charged more and more (cf. Figs. 1C-F).
Upon retracting the first contact member 14, it can get out of its previously established direct electrical contact with the second base 22 (e.g. the direct electrical contact shown merely in Fig. 1C), e.g. the direct electrical contact provided via the receptacle 28. The first contact member 14 can keep its direct electrical contact with the second contact member 24 (cf. Fig. 1D-F).
Later, the direct electrical contact between first contact member 14 and second contact member 24 may be released, with the charged spring accumulator 30 rapidly retracting the second contact member 24, thereby disconnecting the ground connection of the first contact structure 10 via the second contact structure 20 (cf. Fig. 1G). The arc A may form, the duration of existence of the arc A to be minimized by having a rapid movement of the second contact member 24.

Reference signs list

1: Switchgear
2: Switching axis
3: Enclosure

10: First contact structure
12: First base
14: First contact member
16: Guide
18: Receptacle

20: Second contact structure
22: Second base
24: Second contact member
25: Stop element
26: Guide
28: Receptacle
29: Arcing element

30: Spring accumulator

40: Drive system

50: Locking means
52: Metallic tulip
54: Metallic ring

60: Device for disconnecting from ground

100: Electrical system

A: arc
GND: Ground

Claims

Switchgear (1) for breaking an electrical connection, comprising
a first contact structure (10) with a first base (12) and a first contact member (14);

a second contact structure (20) with a second base (22) and a second contact member (24) and corresponding to the first contact structure (10);

a spring accumulator (30) configured for resiliently mounting the first (14) or the second (24) contact member on the respective first (12) or second (22) base;

a drive system (40) configured for at least partially moving the first (14) and the second (24) contact members relative to one another along a switching axis (2) in order to break the electrical connection to ground (GND); and

a locking means (50) configured for locking the first (14) and the second (24) contact members along the switching axis (2) in a releasable manner.
Switchgear (1) according to the preceding claim, wherein
the first contact member (14) is movably held in the first base (12) and coupled to the drive system (40), and

the second contact member (24) is movably held in the second base (22) and resiliently mounted via the spring accumulator (30) on the second base (22).
Switchgear (1) according to one of the preceding claims, wherein
the first contact member (14) is configured for mating on an inside or outside of the first contact member (14) with the second contact member (24) on an outside inside of the second contact member (24), and particularly

the first contact member (14) comprises a tube shape and the second contact member (24) comprises an axially elongated shape for mating on the inside or outside thereof with the outside or inside of the tube shape.
Switchgear (1) according to the preceding claim, wherein
the second base (22) comprises a receptacle (28) for mating on an inside or outside thereof with the outside or inside the first contact member (14) in order to conduct a switching current of at least 160 A.
Switchgear (1) according to one of the preceding claims, wherein
the second contact structure (20) comprises a guide (26) for guiding the second contact member (24) between a first and a second position along the switching axis (2), and

the spring accumulator (30) has a spiral spring and acts along the switching axis (2) and between the second contact member (24) and the guide (26).
Switchgear (1) according to one of the preceding claims, wherein
the locking means (50) includes a metallic tulip (52) and a metallic ring (54), the ring (54) arranged on a front of the first contact member (14) facing the second contact structure (20) and configured for interacting with the tulip (52), the tulip (52) arranged on a circumference of the second contact member (24),

the tulip (52) including spring elements to be compressed by the ring (54) in order to realize a releasable form fit and/or force fit acting along the switching axis (2).
Switchgear (1) according to the preceding claim, wherein
the metallic ring (54) includes tungsten and copper, and

the second contact member (24) is provided on the side facing the first contact structure (10) with an arcing element (29) that includes tungsten and copper.
Switchgear (1) according to one of the preceding three claims, wherein
the second contact member (24) and the guide (26) each comprise a stop element (25), the stop elements (25) configured for stopping against each other in the second position in order to prevent further movement of the second contact member (24).
Switchgear (1) according to one of the preceding claims, comprising
a damping element interacting with the second contact member (24) and particularly with at least one of the stop elements (25).
Switchgear (1) according to one of the preceding claims, comprising
an enclosure (3) configured to be filed with insulating gas, the insulating gas including at least one of SF6 gas, N2 gas and CO2 gas.
Switchgear (1) according to one of the preceding claims, comprising
a device (60) configured for disconnecting the switchgear from ground (GND) in order to conduct measurements on electrical properties of the switchgear (1).
Switchgear (1) according to one of the preceding claims which
is configured for grounding a voltage of at least 245 kV,

is rated with a/the switching current of at least 160 A,

is rated with a recovery voltage of at least 10 kV, and

is rated with a number of operations of at least ten.
Switchgear (1) according to one of the preceding claims, wherein
the second base (22) comprises a cast aluminum part.
Method to operate a switchgear (1) according to one of the preceding claims, comprising
connecting the second contact structure (20) to ground (GND);

moving the first contact member (14) along the switching axis (2) away from the second base (22) for the spring accumulator (30) to get charged while the first (14) and the second (24) contact members are locked along the switching axis (2) in a releasable manner, wherein the locking means (50) releases so that the spring accumulator (30) resiliently moves the first (14) and the second (24) contact member away from one another; and/or

moving the first contact member (14) along the switching axis (2) towards the second base (22) for the first (10) and second (20) contact structures to form an electrical connection and thereby the first contact structure (10) to be connected to ground (GND) and the first (14) and the second (24) contact members to be locked along the switching axis (2) in a releasable manner.
Use of a switchgear (1) according to one of claims 1 to 13 to break an electrical connection of an electrical system (100) to ground (GND).