EP4273900A1

EP4273900A1 - Electrical switching device

Info

Publication number: EP4273900A1
Application number: EP22171749.9A
Authority: EP
Inventors: Zichi ZHANG; Stefan Valdemarsson
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2022-05-05
Filing date: 2022-05-05
Publication date: 2023-11-08

Abstract

An electrical switching device (29) comprises a main contact arrangement comprising a fixed contact (32) and a movable contact (30) moveable along a movement path between a closed position in which it is in contact with the fixed contact (32) and a fully open position in which it is separated from the fixed contact (32), an arc splitting structure comprising a stack of splitter plates and at least one arc rotating coil, where one of the splitter plates at the bottom of the stack is a first outermost splitter plate and another of the splitter plates at the top of the stack is a second outermost splitter plate, an arc quenching circuit (44), an arc runner (34) and a charge connection plate (36), wherein the first outermost splitter plate is mechanically and electrically connected to the fixed contact (32), the arc runner (34) has a first end (34a) electrically and mechanically connected to the second outermost splitter plate (14) and a second end (34b) located adjacent the fixed contact (32) along the movement path and the charge connection plate (36) is located after the arc runner along the movement path and is electrically connected to the arc quenching circuit (44).

Description

TECHNICAL FIELD

The present disclosure generally relates to an electrical switching device for extinguishing an electric arc. In particular it relates to an electrical switching device of a rotating arc type.

BACKGROUND

When interrupting a current in DC systems at zero crossings created by injection currents, a recovery voltage will occur across the post arc. A conventional approach to solve this problem is to introduce an arc chamber with several splitter plates where the arc, running from the main contacts into the arc chamber, will be divided into several short arcs in order to achieve an effective cooling and thereby withstand the fast rising recovery voltage.
At conventional splitter plates the arcs are only allowed to move for short distances. They thereby become stationary and may therefore cause melting damages on the surface of each splitter plate. This melting has several negative consequences. For example, metal vapour in the post arc column will weaken the ability to withstand the recovery voltage. Moreover, the old foot point of the arc is still molten when recovery voltage is applied. The short post arc column will thereby not be cooled effectively. Additionally, melted craters and droplets from the surface of the splitter plates can cause short circuits between plates. Hence at higher currents, typically larger than 5-10kA, the gaps between plates have to be increased, leading to worsened recovery voltage withstand.
One solution to the above problem is to use a so-called rotating arc chamber. One rotating arc chamber is disclosed in WO 2020/127401 , where a stack of splitter plates with loop structure are coaxially stacked between two drive coils.
However, there is room for improvement of switching devices in the use of rotating arc chambers

SUMMARY

In view of the above, an object of the present disclosure is to provide an electrical switching device which solves, or at least mitigates, the problems of the prior art.
There is hence provided and electrical switching device comprising:

a main contact arrangement comprising a fixed contact and a movable contact, the moveable contact being moveable between a closed position in which it is in contact with the fixed contact and a fully open position in which it is separated from the fixed contact,
an arc splitting structure comprising a stack of splitter plates and at least one arc rotating coil, where each splitter plate has a loop structure and the splitter plates are coaxially stacked in the stack with respect to their loop structure around a central axis, wherein one of the splitter plates at the bottom of the stack is a first outermost splitter plate and another of the splitter plates at the top of the stack is a second outermost splitter plate,
an arc quenching circuit,
an arc runner, and
a charge connection plate,

The moveable contact may, in the fully open position, be separated from the fixed contact by a first pre-determined distance and may in the fully open position be separated from the charge connection plate by a second pre-determined distance, where the second distance may be shorter than the first distance.
The charge connection plate may be located after the second end of the arc runner along the movement path from the closed to the fully open position. The second end of the arc runner may be placed along the movement path so that the moveable contact makes contact with it when moving from the closed to the open position. The charge connection plate may be placed along the movement path so that the moveable contact makes contact with it when moving from the closed to the open position.
Furthermore, the fixed contact may have a contact end for connection to a corresponding contact end of the moveable contact in the closed position and the movement path may be a movement path of the contact end of the moveable contact.
The arc runner may be configured to direct a first part of a main arc from the main contact arrangement to the stack of splitter plates to thereby split the first part of the main arc into a plurality of subarcs between the splitter plates and the at least one arc rotating coil may be configured to create a blowing magnetic field in the stack of splitter plates causing the subarcs to move circumferentially along the loop structures of the splitter plates.
The arc quenching circuit may be connected between the fixed contact and the charge connection plate. The arc quenching circuit may additionally comprise a capacitor connected between the fixed contact and the charge connection plate. The capacitor may be uncharged when the moveable contact is in the closed position.
The arc splitting structure, arc runner and charge connection plate may be part of a discharge loop for the capacitor, where the discharge loop has an inductance that together with a capacitance of the capacitor forms a resonance frequency of the arc quenching circuit. Alternatively, the capacitor may be connected in series with an inductor for obtaining resonance.
The arc quenching circuit may additionally comprise a surge arrester connected between the fixed contact and the charge connecting plate.
In the arc splitting structure, there may be an arc rotating coil at the top of the stack electrically connected to the second outermost splitter plate and the arc runner. There may additionally be an arc rotating coil at the bottom of the stack electrically connected to the first outermost splitter plate and the fixed contact.
Furthermore, the splitter plates may be organized in arc chambers, where there maybe n arc chambers and (n+1) arc rotating coils in the stack, where n may be equal to or higher than two. There may additionally be an intermediate arc rotating coil between the splitter plates of each arc chamber.
A splitter plate at the bottom of an arc chamber may be electrically connected to the splitter plate at the top of a neighbouring arc chamber. The arc rotating coils may be connected in the arc splitting structure in such a way that current directions around the central axis in two neighbouring arc rotating coils are opposite to each other.
The electrical switching device may be a contactor or a circuit breaker.
The invention has a number of advantages. Melting of arc plates is avoided. The design has the additional advantage of utilizing the arc to connect the arc extinguishing circuit. This can be used to generate an injection current that provides current zero-crossing in sub-arcs in the stack. The device may because of this be made compact. If the distance between the charge connection plate and the moveable contact in the open position is sufficient, it is additionally possible that the moveable contact acts as a disconnector.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, etc., unless explicitly stated otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

The specific embodiments of the inventive concept will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 schematically shows a first stack of splitter plates and arc rotating coils used for forming a first arc splitting structure centred around an axis;
Fig. 2 shows a cross-sectional-view of a second stack of splitter plates forming a second arc splitting structure also centred around an axis;
Fig. 3 schematically shows an electrical switching device comprising a main contact arrangement, an arc runner, a charge connection plate, an arc quenching circuit and arc rotating chambers for the arc plates of the second arc splitting structure; and
Fig. 4 - 8 schematically shows the switching device during different stages in an opening and arc quenching operation of the electrical switching device.

DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplifying embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description.
Aspects of the present disclosure are concerned with a stack of splitter plates and arc rotating coils used to form an arc splitting structure. In such a stack there may be at least two splitter plates and at least one arc rotating coil. Fig. 1 shows an example of a first stack 10a that comprises three splitter plates 12, 14 and 16 and two arc rotating coils 18 and 20 forming a first arc splitting structure 10a for use in an electrical switching device.
Each splitter plate 12, 14 and 16 has a loop structure and is centred around a longitudinal axis AX. The splitter plates 12, 14 and 16 may hence have through-openings formed by the loop structure. Alternatively, the splitter plates are solid, i.e. without through-openings. In this case an inner distancing element and an outer distancing element arranged concentrically with the inner distancing element may be provided between each pair of adjacent splitter plates, forming the loop structure.
The splitter plates 12, 14, 16 are placed in the stack such that one splitter plate is a first outermost splitter plate 12 and another splitter plate is a second outermost splitter plate 14. The first outermost splitter plate 12 is the outermost splitter plate on one side of the stack 10a. The second splitter plate 14 is the outermost splitter plate on another opposite side of the stack 10a. The first outermost splitter plate 12 may additionally be placed at the bottom of the stack 10a, while the second outermost splitter plate 14 may be placed at the top of the stack 10a. Between the first and second outermost splitter plates there may be one or more intermediate splitter plates. In this case there is one intermediate splitter plate 16.
The splitter plates 12, 14, 16 are stacked such that the loop structures are arranged coaxially along the axis AX. The splitter plates 12, 14, 16 may additionally be stacked with an axial gap between each other.
The splitter plates 12, 14, 16 may be made of a non-ferrous, non-magnetic material such as copper or brass.
There is also a first outermost arc rotating coil 18 at the bottom of the stack 10a and a second outermost arc rotating coil 20 at the top of the stack 10a, where the first outermost arc rotating coil 18 is located below and electrically or galvanically connected to the first outermost splitter plate 12 (not shown) and the second outermost arc rotating coil 20 is placed at the top of the stack 10a above and electrically or galvanically connected to the second outermost splitter plate 14. The first outermost arc rotating coil 18 is connected to the first outermost splitter plate 12 in such a way that a current running through it around the central axis AX is opposite to the direction of the current through the first outermost splitter plate 12. The second outermost arc rotating coil 20 is in an analogous way connected to the second outermost splitter plate 14 in such a way that a current running through it around the central axis AX is opposite to the direction of the current through the second outermost splitter plate 14. How this may be done is described in more detail in WO 2020/127401 , which is herein incorporated by reference.
Through this realization there is one arc rotating coil at the top and bottom of the stack. At least the splitter plates 12, 14, 16 of the stack 10a may be placed in an arc chamber. It is also possible that the arc rotating coils 18 and 20 are placed in the arc chamber. However, it is also possible that they are placed outside of it.
Fig. 2 shows a cross-sectional view of a second stack 10b of splitter plates and arc rotating coils forming a second arc splitting structure.
In the second stack there may generally be n groups of splitter plates and n+i arc rotating coils, where n is an integer that is equal to or higher than two. n is with advantage three or four. In the example in fig. 2 n is equal to three. Each group of splitter plates may additionally be enclosed in an arc chamber.
In the example of fig. 2, there is a first outermost arc rotating coil 18 and a first outermost splitter plate 12 at the bottom of the stack 10b as well as a second outermost splitter plate 14 and a second outermost arc rotating coil 20 at the top of the stack 10b, where the first outermost arc rotating coil 18 is placed below the first outermost splitter plate 12 and the second arc rotating coil 20 is placed above the second outermost splitter plate 14. Thereby the first outermost arc rotating coil 18 is placed at the bottom of the stack 10b and the second outermost arc rotating coil 20 is placed at the top of the stack 10b. Moreover, the first outermost splitter plate 12 is a splitter plate in a first group 25 of splitter plates in the stack 10b and the second outermost splitter plate is a splitter plate in a last group 27 of splitter plates in the stack 10b. There is also a second group 26 of splitter plates in the stack above the first group 25 of splitter plates and below the last group 27 of splitter plates. Each group of splitter plates is additionally separated from a neighbouring group of splitter plates by an intermediate arc rotating coil 28.
Furthermore, a splitter plate at the bottom of such a group is electrically connected to a splitter plate at the top of a neighbouring group located below it. Both these splitter plates are additionally connected to the intermediate arc rotating coil placed between the two groups.
This means that for the example of fig. 2, a splitter plate 22 at the bottom of the last group 27 is connected to a splitter plate 24 at the top of the second group 26 via an intermediate arc rotating coil 28, while a splitter plate 22 at the bottom of the second group 26 is connected to a splitter plate 24 at the top of the first group 25 via an intermediate arc rotating coil 28. Additionally, the first outermost splitter plate 12 is separated from the splitter plate 24 at the top of the first group 25 by an intermediate splitter plate 16, the splitter plate 22 at the bottom of the second group 26 is separated from the splitter plate 24 at the top of the second group 26 by an intermediate splitter plate 16 and the splitter plate 22 at the bottom of the last group 27 is separated from the second outermost splitter plate 14 by an intermediate splitter plate 16. It should here be realized that it is possible with more as well as fewer splitter plates in each group.
Each group of splitter plates is furthermore supposed to be enclosed in an arc chamber. There is thus a first, second and last arc chamber for the first, second and last groups of splitter plates 25, 26, 27.
It can thereby be seen that a splitter plate at the bottom of an arc chamber is electrically connected to the splitter plate at the top of a neighbouring arc chamber (located below it in the stack) and where these two splitter plates are electrically connected to each other via an intermediate arc rotating coil.
An intermediate arc rotating coil 28 that separates two groups of splitter plates may be placed outside of or inside one of the arc chambers provided for the groups. The first outermost arc rotating coil 18 can likewise be placed outside of or inside the arc chamber for the first group 25 of splitter plates and the second outermost arc rotating coil 20 can be placed outside of or inside the arc chamber for the last group 27 of splitter plates.
Furthermore, also the current through neighbouring arc rotating coils run in opposite directions. The current through the intermediate arc rotating coil 28 placed between the first and the second groups 25, 26 of splitter plates thus runs in an opposite direction to the current through the first outermost arc rotating coil 18. The current through the intermediate arc rotating coil 28 placed between the second and the last groups 26, 27 of splitter plates thus runs in an opposite direction to the current through the intermediate arc rotating coil 28 placed between the first and the second groups 25, 26 of splitter plates. The current through the second outermost arc rotating coil 20 runs in an opposite direction to the current through the intermediate arc rotating coil 28 placed between the second and the last groups 26, 27 of splitter plates. Thereby the direction of magnetic flux density of two adjacent coils and the directions of magnetic field coincide in an arc chamber.
This has the effect of magnetic fields of arc rotating coils enhancing each other and thereby the rotation of an arc in an arc chamber is improved in an arc chamber compared with the use of only one arc rotating coil for the arc chamber.
Fig. 3 schematically shows an electrical switching device 29 that comprises the second arc splitting structure. The switching device 29 may be a medium voltage direct current (MVDC) switching device for operation in an MV range of for instance 2-20 kV. The switching device 29 comprises an arc runner 34 having a first and a second end 34a and 34b, a charge connection plate 36, an arc quenching circuit 44 comprising a surge arrester 46 in parallel with a capacitor 48 and having a first and a second end, a contact arrangement comprising a fixed contact 32 with a first contact end 32a and a moveable contact 30 with a second contact end 30a as well as a stack of arc chambers comprising n arc chambers 38, 40 and 42, one for each group of splitter plates). There is thus a first arc chamber 38 for the first group of splitter plates, a second arc chamber 40 for the second group of splitter plates and a last arc chamber 42 for the last group of splitter plates, where the first arc chamber 38 is electrically connected to the second arc chamber 40 and the second arc chamber 40 is electrically connected to the last arc chamber 42, where these connections are made through electrically interconnecting a splitter plate at the bottom of a group with a splitter plate at the top of a neighbouring group lower down in the stack.
Furthermore, the first outermost splitter plate of the stack is electrically connected to the fixed contact 32 as well as to the first outermost arc rotating coil, while the second outermost splitter plate is connected to a first end 34a of the arc runner 34 as well as to the second outermost arc rotating coil. The arc runner 34 may thereby be in direct mechanical contact with the second outermost splitter plate. The arc runner 34 may also be integral with the second outermost splitter plate.
The moveable contact 30 of the main contact arrangement is moveable between a closed position in which the contact end 30a of it is in mechanical and electrical contact with the contact end 32a of the fixed contact 32 and a fully open position in which the contact end 30a of the movable contact 30 is separated from the contact end 32a of the fixed contact (at a pre-determined distance or location).
The first end of the arc quenching circuit 44 is connected to the first outermost splitter plate of the first arc chamber 38 as well as to the fixed contact 32. The first end 34a of the arc runner 34 is connected to the second outermost splitter plate of the last arc chamber 42. The arc runner 34 then runs beside the stack of splitter plates and the second end 34b is placed adjacent the contact end 32a of the fixed contact 32. The second end 34 may more particularly be placed at a location that the contact end 30 of the moveable contact 30 passes when moving from the closed to the fully open position. The second end 34b of the arc runner 34 is thus located along a path between the closed and a fully open position of the contact end 30a of the moveable contact 30. The second end 34b of the arc runner 34 may additionally be placed along the movement path so that the contact end 30a of the moveable contact 30 makes contact with or is close to the second end 34b of the arc runner 34 when moving from the closed to the open position. The charge connection plate 36 is also placed along the path between the closed and fully open position of the contact end 30a of the moveable contact30. It is more particularly placed after the second end 34b of the arc runner 34 in the path. It is thus placed closer to the fully open position than is the second end 34b of the arc runner 34. The charge connection plate 36 is additionally electrically connected to the second end of the arc quenching circuit 44. It is possible that the contact end 30a of the moveable contact 30 makes electrical contact with the charge connection plate 36 as it passes it. The charge connection plate 36 may thereby be placed along the movement path so that the contact end 30a of the moveable contact 30 makes contact with it when moving from the closed to the open position. There may additionally be a gap between the charge connection plate 36 and the moveable contact 30 in the fully open position, which may be a gap long enough to ensure the avoidance of arc reignition. The moveable contact 30 may in the fully open position be separated from the contact end 32a of the fixed contact 32 by a first pre-determined distance and be separated from the charge connection plate 36 by a second pre-determined distance, where the second distance may correspond to the above-mentioned gap and may be shorter than the first distance.
The arc runner 34 is configured to direct a first part of a main arc initially generated between the moveable contact 30 and the fixed contact 32 when the movable contact 30 is moved from the closed to the fully open position, as subarcs to the stack of splitter plates in the arc chambers 38, 40, 42. The charge connection plate 36 is in turn configured to provide an arc extinguishing current from the arc quenching circuit 44 to the arc chambers 38, 40, 42 via the arc runner 34 providing a current zero-crossing for the subarcs in the arc chambers 38, 40, 42 as well as to allow the surge arrester 46 to quench a second part of the main arc.
The operation of the electrical switching device will now be described with reference being made to fig. 4-8, which shows the movement of the movable contact 30 from the closed to the fully open position as well as the occurrence, splitting and quenching of arcs during the movement.
The capacitor 48 is initially uncharged. It does not have any voltage, which means that the potential at the second end of the arc quenching circuit 44 is the same as the potential at the first end. Also, the surge arrester 46 has a voltage level at which it is set to conduct. This voltage level is typically chosen to be somewhat higher than the voltage of the voltage source of the main circuit which is to be interrupted by the load switch.
When the movable contact 30 is started to be moved from the closed to the fully open position, a main arc is created between the fixed and the moveable contact 32, 30. As the contacting end 30a of the moveable contact 30 passes by and perhaps also makes mechanical contact with the second end 34b of the arc runner 34, the main arc commutates to the arc runner 34, as can be seen in fig. 4.
As the moveable contact 30 is continued to be moved past the arc runner 34, the main arc is split, as can be seen in fig. 5, into a first part between the arc runner 34 and the fixed contact 32 and a second part between the arc runner 34 and the moveable contact 30 where the second part may be between the second end 34b of the arc runner 34 and the contact end 30a of the moveable contact 30. The first part may additionally be extended and run towards the arc chambers 38, 40 and 42.
As the movable contact 30 continues to move towards the fully open position it passes by the charge connection plate 36, where the contact end 30a of the moveable contact 30 may additionally connect with the charge connection plate 36 during this passage. As can be seen in fig. 6, the first part of the main arc has now moved into the stack and is split into subarcs in the arc chambers 38, 40, 42, which subarcs are rotated by the arc rotating coils through the arc rotating coils creating a blowing magnetic field in the stack of splitter plates causing the subarcs to move circumferentially along the loop structures of the splitter plates. The second part of the main arc has in turn moved so that it now connects the contact end 30a of the moveable contact 30 with the charge connection plate 36, which in turn causes the voltage of the arc chambers 38, 40, 42 to be applied across the capacitor 48. Thereby the capacitor 48 is charged. A charge current may thereby run in a loop from the first end of the arc quenching circuit 44 via the first, second and third arc chambers 38, 40, 42, the arc runner 34 and the charge connection plate 36 to the second end of the arc quenching circuit 44. This current is additionally a resonance current, the frequency of which is determined by the capacitance of the capacitor 48 and the inductance of the loop. The capacitor 48 thus starts to generate and inject an injection current into the arc chambers 38, 40, 42, which injection current runs from a first end of the capacitor 48 to the arc chambers 38, 40, 42 and then back to a second end of the capacitor 48 via the arc runner 34 and charge connection plate 36. Thereby a current zero-crossing is injected into the loop which quenches the subarcs and the arc between the arc runner 34 and the charge connection plate 36. The injected current thus creates a current zero-crossing in the arcs that rotate in the arc chambers 38, 40, 42, and thereby the current through the arc chambers is interrupted, as can be seen in fig. 7.
In this stage, when the arcs in the arc chambers 38, 40 42 are extinguished, the main dc-current continues to flow through the moveable contact 30 through the residual arc between the contact end 30a of the moveable contact 30 and charge connection plate 36 and through the capacitor 48, thereby charging the capacitor 48 up to the voltage level of the surge arrester.
When the voltage of the capacitor 48 reaches the voltage level of the surge arrester 46, the main current will continue to flow in the surge arrester 46 instead of the capacitor 48. This will continue for some milliseconds, depending on the time constant of the main circuit, until the energy stored in the main circuit is emptied into the surge arrester 46 and the main dc-current finally is interrupted. At the same time the residual arc between the contact end 30a of the moveable contact 40 and the charge 36 will extinguish.
Moreover, the second part of the arc current passes from the moveable contact 30 to the surge arrester 46 via the charge connection plate 36 and is thereby quenched by the surge arrester 46 so that the current is eventually completely interrupted. The moveable contact 30 then continues to the fully open position, as is shown in fig. 8.
It can thereby be seen that an MVDC load switch is provided using a number of serial rotating arc chambers, such as 3 - 4 stacked arc chambers each comprising a corresponding group of splitter plates, together with an arc quenching circuit comprising one or more non pre-charged capacitors and one or more surge arresters.
This design provides multiple rotating arc chambers that can have a higher voltage rating, for instance up to around 15kV, than a switch with a single, rotating arc chamber, where voltage rating of a design with a single arc chamber is typically around 4 or 5kV.
Through electrically connecting the splitter plates of the arc chambers it is also possible to obtain a stable rotation of all arcs between splitter plates.
The design has the additional advantage of utilizing the arc to connect the capacitor of the arc extinguishing circuit and generate injection current that provides current zero-crossing in the sub-arcs of the arc chambers. According to the design an uncharged capacitor may be used and therefore the capacitor may be made small, which allows the device to be compact. If the distance between the charge connection plate and the moveable contact in the open position is sufficient, it is additionally possible that the moveable contact also acts as a disconnector.
The rotation of the subarcs has the advantage of protecting the splitter plates from melting and thereby providing an excellent recovery voltage withstand capability.
In the switching device described above, three arc chambers with the second stack with the second arc splitting structure was used. It should be realized that this structure can be varied according to the previously described principles using n groups of splitter plates and n+1 arc rotating coils, where n is higher than or equal to two. It is also possible that the first arc splitting structure is used instead with one or two arc splitting coils.
The splitter plates may generally have any structure, preferably with rounded corners. The splitter plates may hence for example be circular or polygonal with rounded corners.
The inventive concept has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.

Claims

An electrical switching device (29) comprising:
a main contact arrangement comprising a fixed contact (32) and a movable contact (30), the moveable contact (30) being moveable between a closed position in which it is in contact with the fixed contact (32) and a fully open position in which it is separated from the fixed contact (32),

an arc splitting structure (10A, 10B) comprising a stack of splitter plates (12, 14, 16; 12, 14, 16, 22, 24) and at least one arc rotating coil (18, 20; 18, 20, 28), where each splitter plate has a loop structure and the splitter plates are coaxially stacked in the stack with respect to their loop structure around a central axis (AX), wherein one of the splitter plates at the bottom of the stack is a first outermost splitter plate (12) and another of the splitter plates at the top of the stack is a second outermost splitter plate (14),

an arc quenching circuit (44),

an arc runner (34), and

a charge connection plate (36),
wherein the first outermost splitter plate (12) is mechanically and electrically connected to the fixed contact (32), the arc runner (34) has a first end (34a) being electrically and mechanically connected to the second outermost splitter plate (14) and a second end (34b) located adjacent the fixed contact (32) along a movement path of the moveable contact (30) from the closed to the fully open position and the charge connection plate (36) is located after the arc runner along said movement path and is electrically connected to the arc quenching circuit (44).
The electrical switching device (29) as claimed in claim 1, wherein the fixed contact (32) has a contact end (32a) for connection to a corresponding contact end (30a) of the moveable contact (30) in the closed position and the movement path is a movement path of the contact end (30a) of the moveable contact (30).
The electrical switching device (29) as claimed in claim 1 or 2, wherein the arc runner (34) is configured to direct a first part of a main arc from the main contact arrangement to the stack of splitter plates (10a, 10b) to thereby split the first part of the main arc into a plurality of subarcs between the splitter plates (12, 14, 16; 12, 14, 16, 22, 24) and the at least one arc rotating coil (18, 20; 18, 20, 28) being configured to create a blowing magnetic field in the stack of splitter plates (12, 14, 16; 12, 14, 16, 22, 24), causing the subarcs to move circumferentially along the loop structures of the splitter plates.
The electrical switching device (29) as claimed in any previous claim, wherein the arc quenching circuit (44) is connected between the fixed contact (32) and the charge connection plate (36).
The electrical switching device (29) as claimed in claim 4, wherein the arc quenching circuit (44) comprises a capacitor (48) connected between the fixed contact (32) and the charge connection plate (36).
The electrical switching device (29) as claimed in claim 5, wherein the capacitor (48) is uncharged when the moveable contact (30) is in the closed position.
The electrical switching device (29) as claimed in claim 5 or 6, wherein the arc splitting structure, arc runner (34) and charge connection plate (36) are part of a discharge loop for the capacitor (48), said discharge loop having an inductance that together with a capacitance of the capacitor (48) forms a resonance frequency of the arc quenching circuit (44).
The electrical switching device (29) as claimed in any of claims 4-7, wherein the arc quenching circuit (44) comprises a surge arrester (46) connected between the fixed contact (32) and the charge connecting plate (36).
The electrical switching device (29) as claimed in any previous claim, wherein there is an arc rotating coil (20) at the top of the stack (10a; 10b) electrically connected to the second outermost splitter plate (14) and the arc runner (34).
The electrical switching device (29) as claimed in any previous claim, wherein there is an arc rotating coil (18) at the bottom of the stack (10a; 10b) electrically connected to the first outermost splitter plate (12) and the fixed contact (32).
The electrical switching device (29) as claimed in claim 10 when depending on claim 9, wherein the splitter plates (12, 14, 16, 22, 24) are organized in arc chambers (38, 40, 42), where there are n arc chambers (38, 40, 42) and (n+i) arc rotating coils (18, 20, 28) in the stack, where n ≥ 2 and there is an intermediate arc rotating coil (28) between the splitter plates of each arc chamber (38, 40, 42).
The electrical switching device (29) as claimed in claim 11, wherein a splitter plate (22) at the bottom of an arc chamber (40, 42) is electrically connected to the splitter plate (24) at the top of a neighbouring arc chamber (38, 40) (located below it in the stack).
The electrical switching device (294) as claimed in claim 12, wherein the arc rotating coils are connected in the arc splitting structure in such a way that current directions around the central axis (AX) in two neighbouring arc rotating coils are opposite to each other.
The electrical switching device (29) as claimed in any previous claim, wherein the charge connection plate (36) is located after the second end (34b) of the arc runner (34) along the movement path of the moveable contact (30) from the closed to the fully open position.
The electrical switching device (29) as claimed in any previous claim, wherein the charge connection plate (36) is placed along the movement path so that the moveable contact (30) makes contact with it when moving from the closed to the open position.