Disconnector contact system with controlled discharge

Abstract

Embodiments herein provide a gas insulated disconnector (300) for an electrical device (200), comprising a first contact (310) and a second contact (320) having a longitudinal central axis. At least one of the first contact (310) and the second contact (320) is movable in a direction of a longitudinal central axis of the first contact (310), where the first contact (310) is connected to the second contact (320) in a closed position and is disconnected from the second contact (320) in an open position. The second contact (320) includes a predetermined contact portion (325) having a roughness higher than that of an adjacent contact portion of the second contact (320), where the predetermined contact portion (325) is closer to the longitudinal center axis of the first contact (310) than the adjacent contact portion.

Description

Technical Field

[0001] This disclosure generally relates to a gas-insulated high-voltage device. More specifically, this disclosure relates to a contact system of a switching device having a controlled discharge root point. Background Technology

[0002] Switchgear is used to isolate electrical installations from power lines or to disconnect one part of a power line from another. Switchgear includes disconnecting switches (DS) (e.g., vertical break disconnecting switches) and / or grounding switches. A DS is a mechanical switch adapted to connect or disconnect electrical installations from power lines. In high-voltage environments, DS are typically used to create a visible disconnect point to ensure reliable isolation of electrical installations from power lines, allowing the installations to be safely operated or maintained without load. Figure 1 As shown, the DS100 has a contact system comprising two contacts: a movable contact 110 and a fixed contact 120, both housed in an enclosed chamber. Under normal conditions, the two contacts 110 and 120 remain connected (i.e., in the closed position). When the DS needs to disconnect a portion of the switching device, the two contacts 110 and 120 separate (i.e., in the open position) to interrupt the circuit.

[0003] Typically, when the disconnector 100 is in operation at the supply voltage, the moving contact 110 switches between a closed and open position during switching operations (e.g., bus charging current switching). Due to the action of the moving contact 110, sparks or capacitive discharges (i.e., pre-breakdown or re-breakdown discharges) may occur between the two contacts 110 and 120 during bus charging current switching. For example, during closing, a spark may occur before the moving contact 110 has reached / touched the stationary contact 120. During opening, a spark may occur before the moving contact 110 has reached the fully open position. Furthermore, current continues to flow between the two contacts 110 and 120 through the spark. The enclosed compartment containing the two contacts 110 and 120 can contain a fluid insulating medium (liquid or gas) that extinguishes / extinguishes the sparks formed between the two contacts 110 and 120.

[0004] Furthermore, under certain conditions, the resulting discharge / spark can cause a destructive discharge from the contact system of the disconnector to the housing (i.e., ground potential), leading to internal sparking and malfunction of the DS. For example, in Figure 1 The image depicts a discharge / spark (i.e., pre-breakdown or re-breakdown discharge) formed between contacts 110 and 120 in a partially closed contact system, wherein the movable contact 110 is fixed in a certain position under multiple voltage applications.

[0005] Utilizing the existing design of the contact system of the disconnector 100 as described above, discharge / sparking can typically begin at or near the leading edge (tip) of the moving contact 110, where the moving contact 110 can be located close to or even on the outer tube surface of the moving contact 110. Therefore, this discharge may have a higher probability of causing a destructive spark / discharge to the housing compared to a discharge / sparking that begins closer to the inner tube surface of the moving contact 110.

[0006] Furthermore, the spark / discharge generated between contacts 110 and 120 may come into contact with the enclosed chamber or any other component of the DS that may be at the housing / ground potential, thereby damaging components of the disconnecting switch 100 / DS. For example, Figure 2A , Figure 2B , Figure 2C and Figure 2D The diagrams depict how sparks propagate and make contact with any other components of the DS that may be at the enclosure / ground potential. These diagrams are adapted from the Cigré manual (CigréBrochure). Summary of the Invention

[0007] Using the existing design of DS disconnectors, sparks can begin at or near the leading edge of the moving contact, close to or even on the outer surface of the moving contact. This type of spark has a higher probability of contacting the DS enclosure or any other DS component at ground potential compared to sparks that may begin closer to the inner surface of the moving contact or the longitudinal central axis.

[0008] The likelihood of this undesirable off-center discharge is greater when the moving contact is subjected to positive potential stress during the bus charging current switching operation. In this configuration, due to the lack of the initial electron to initiate the discharge, the discharge root point may spread more widely on the moving contact. For statistical reasons, discharge may occur at undesirable off-center locations.

[0009] In most cases, neither of the two contacts of a disconnecting switch is specifically designed, and therefore sparks can originate from an undesirable point on the moving contact. Consequently, it is difficult to limit the spark to the axial center of the disconnecting switch, and even more difficult to prevent the spark from contacting the chamber or any other component of the DS that may be at ground potential.

[0010] The problem of the lack of the first electron causing discharge on the positive stress moving contact can be overcome by providing the first electron from the negative stress fixed contact side by field emission.

[0011] Therefore, there is a need for a disconnecting switch having at least one of two contacts designed such that sparks are confined to the axial center of the disconnecting switch, thereby preventing sparks from contacting the enclosed chamber or any other component of the DS that may be at ground potential.

[0012] Therefore, the purpose of this disclosure is to provide a disconnecting switch for electrical equipment to mitigate, alleviate, or eliminate all or at least some of the disadvantages of the currently known solutions discussed above.

[0013] This and other objectives are achieved by means of the disconnecting switch as defined in the appended claims. The term "exemplary" is to be understood in this context as an example, illustration, or description.

[0014] According to one aspect of this disclosure, a disconnecting switch for an electrical device is provided. The disconnecting switch includes a first contact and a second contact having a longitudinal central axis, wherein at least one of the first and second contacts is movable in the direction of the longitudinal central axis of the first contact, wherein the first contact is connected to the second contact in a closed position, wherein the first contact is disconnected from the second contact in an open position, wherein the second contact includes a predetermined contact portion having a roughness higher than that of an adjacent contact portion of the second contact, and wherein the predetermined contact portion is closer to the longitudinal central axis of the first contact than the adjacent contact portion.

[0015] Field emission requires appropriate roughness on either the first or second contact. Ions generated by field emission can drift along the field lines to the other contact, where they can detach from electrons and trigger a spark / discharge.

[0016] Advantageously, using the proposed disconnecting switch, when this increased roughness is applied to the FC side at the location where negative ions are transported to the desired location to initiate a discharge on the MC, the discharge / spark formed between the two contacts can occur closer to the longitudinal central axis of the first contact. As a result, the shielding effect of the fixed electrodes at the first and second contacts on the discharge path can be maximized.

[0017] Furthermore, by utilizing the proposed isolating switch, the risk of destructive discharge to the casing (i.e., ground potential) (i.e., pre-breakdown or re-breakdown formed between the two contacts) can be reduced during the switching of the bus charging current. This risk of destructive discharge can be further reduced by centering the discharge / spark path closer to the longitudinal central axis of the first contact.

[0018] In some embodiments, the minimum roughness of the predetermined contact portion of the second contact has an arithmetic mean roughness value Ra of 1 micrometer, a total height Rt of the roughness profile of 8 micrometers, and an average roughness depth Rz of 4 micrometers.

[0019] In some embodiments, the minimum roughness of the predetermined contact portion of the second contact has an arithmetic mean roughness value Ra of 2 micrometers, a total height Rt of the roughness profile of 15 micrometers, and an average roughness depth Rz of 7 micrometers.

[0020] In some embodiments, the minimum roughness of the predetermined contact portion of the second contact has an arithmetic mean roughness value Ra of 5 micrometers, a total height Rt of the roughness profile of 30 micrometers, and an average roughness depth Rz of 20 micrometers.

[0021] In some embodiments, the maximum roughness of the predetermined contact portion of the second contact has an arithmetic mean roughness value Ra of 20 micrometers, a total height Rt of a roughness profile of 120 micrometers, and an average roughness depth Rz of 80 micrometers.

[0022] In some embodiments, the maximum roughness of the predetermined contact portion of the second contact has an arithmetic mean roughness value Ra of 15 micrometers, a total height Rt of a roughness profile of 90 micrometers, and an average roughness depth Rz of 60 micrometers.

[0023] In some embodiments, the maximum roughness of the predetermined contact portion of the second contact has an arithmetic mean roughness value Ra of 10 micrometers, a total height Rt of the roughness profile of 60 micrometers, and an average roughness depth Rz of 40 micrometers.

[0024] In some embodiments, the first contact has an end face pointing toward the second contact, and wherein, in the open position, a predetermined contact portion of the second contact is closest to the first contact compared to other contact portions of the second contact.

[0025] In some embodiments, the first contact is movably arranged in the direction of the longitudinal central axis, and the second contact is a fixed contact.

[0026] In some embodiments, the predetermined contact portion having increased roughness is made of aluminum alloy.

[0027] In some embodiments, the predetermined contact portion with increased roughness is defined by a circular region having a central axis aligned with the longitudinal central axis of the first contact, wherein the circular region has a radius smaller than the radius of the outer periphery of the first contact.

[0028] In some implementations, the radius of the predetermined contact portion is smaller than the radius of the inner periphery of the first contact.

[0029] In some embodiments, the disconnecting switch includes a dielectric shield surrounding a first contact. The dielectric shield extends to the end region of the first contact adjacent to a second contact. The present invention prevents deterioration of the shield due to sparks reaching the outer periphery by directing sparks to the center (inner periphery) of the first contact portion rather than its outer periphery.

[0030] In some embodiments, the disconnecting switch includes an insulating medium between a first contact and a second contact, wherein the insulating medium includes at least one of sulfur hexafluoride (SF6), air, carbon dioxide (CO2), oxygen (O2), a mixture of fluoroketones, and a mixture of nitriles.

[0031] In some implementations, one or more of the first and second contacts are tubular.

[0032] Advantageously, by utilizing the proposed arrangement of the first and second contacts and the specific design of the electrode geometry of the first contact, a discharge / spark can be generated from a predetermined contact portion. Therefore, the path of the discharge / spark is centered by shifting it closer to the longitudinal central axis of the first contact.

[0033] Other advantages will be apparent to those skilled in the art. Certain embodiments may have some or all of the advantages described. Attached Figure Description

[0034] The foregoing will be apparent from the following more detailed description of the exemplary embodiments shown in the accompanying drawings, in which similar reference numerals consistently refer to the same parts in different views. The drawings are not necessarily to scale, but rather focus on illustrating exemplary embodiments.

[0035] Figure 1 A schematic diagram of an example disconnecting switch according to the prior art is disclosed (adapted from Cigré manual 260);

[0036] Figure 2A , Figure 2B , Figure 2C and Figure 2D An example path is disclosed for a spark that establishes contact with an enclosed chamber or any other component of a disconnecting switch DS at the enclosure / ground potential, according to the prior art (adapted from Cigré manual 260);

[0037] Figure 3 A schematic diagram illustrating an example disconnecting switch according to some embodiments is disclosed; and

[0038] Figure 4 A schematic diagram illustrating an example disconnecting switch according to some embodiments is disclosed. Detailed Implementation

[0039] Various aspects of this disclosure will be described more fully below with reference to the accompanying drawings. However, the DS disclosed herein can be implemented in many different forms and should not be construed as limited to the aspects set forth herein. Similar numerals in the drawings always refer to similar elements.

[0040] The terminology used herein is for the purpose of describing specific aspects of this disclosure only and is not intended to limit the invention. It should be emphasized that, when used in this application, the term "comprising / including" is used to specify the presence of the stated feature, integers, steps, or components, but does not exclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. As used herein, the singular forms "a," "an," and "the" are intended to also include the plural forms unless the context clearly indicates otherwise.

[0041] Figure 3 A schematic diagram of an example disconnecting switch 300 is disclosed. Electrical device 200 may be a disconnecting switch DS. DS may be a switching device capable of generating, conducting, and disconnecting current in a circuit under normal conditions. DS may also be configured to generate, conduct, and automatically disconnect current in a circuit under specified abnormal conditions for a specified time period. In one example, the specified abnormal condition may be a short-circuit fault.

[0042] The disconnector switch 300 mentioned herein can be applied to electrical equipment 200. The disconnector switch 300 can be a gas-insulated switchgear (GIS) disconnector switch or a hybrid technology switchgear (MTS) switchgear, which is a combination of components of an air-insulated switchgear (AIS), or a combination of an AIS and a GIS disconnector switch. The disconnector switch 300 includes a contact system having at least two contacts (a first contact 310 and a second contact 320). At least one of the two contacts, i.e., the first contact 310 or the second contact 320, can have a tubular shape, resembling a tube, and is long, circular, and hollow. In one example, such as... Figure 3 As shown, the first contact 310 has a tubular shape. At least one of the two contacts configured to move is a moving contact MC, such as the first contact 310, and the other of the two contacts can be a fixed contact FC, such as the second contact 320. Therefore, in some embodiments described herein, the terms first contact, moving contact, and MC are used interchangeably. Similarly, the terms second contact and FC are used interchangeably.

[0043] The two contacts 310 and 320 are electrical conductors and can be at potential during DS operation. The first contact 310 and the second contact 320 can be placed in an enclosed chamber. The enclosed chamber can contain a fluid insulating medium (liquid or gas).

[0044] During a switching operation (e.g., bus charging switching current), the first contact 310 switches between a closed position and an open position. Due to the switching of the first contact 310, a spark or discharge (i.e., pre-breakdown or re-breakdown discharge) may occur between the first contact 310 and the second contact 320. The fluid insulating medium in the enclosed chamber extinguishes / suppresses the spark. The insulating medium in the DS that performs the circuit interruption can be, but is not limited to, one or more of the following: oil, air-break, air jet, sulfur hexafluoride (SF6), organic gases (air, CO2, O2, etc.), vacuum, etc.

[0045] More specifically, in the two contacts, when the first contact 310 begins to move or separates from the second contact 320, the insulating medium between the two contacts 310 and 320 experiences significantly high electrical stress. This electrical stress can be approximately inversely proportional to the distance between the first contact 310 and the second contact 320. At the instant the first contact 310 and the second contact 320 separate, the insulating medium between the first contact 310 and the second contact 320 may break down due to the high electrical stress. Breakdown of the insulating medium may lead to the formation of a conductive path or spark between the first contact 310 and the second contact 320. As the first contact 310 moves further away from the second contact 320, the spark is drawn along with the movement of the first contact 310. Current continues to flow between the first contact 310 and the second contact 320 through the spark, and therefore, the interruption of current is ineffective. The interruption of current can only be considered effective when the spark eventually extinguishes / is put out and thus ceases to exist.

[0046] In most cases, the first contact 310 and the second contact 320 of the disconnector 300 are not specifically designed, and therefore sparks can originate from any point on the first contact 310, i.e., from an undesirable point on the first contact 310. Such sparks / discharges may have a higher probability of causing destructive sparks to the housing (i.e., ground potential). Furthermore, it may be difficult to limit the spark to remain on the longitudinal central axis of the first contact 310. Therefore, it may be difficult to avoid the spark coming into contact with other components of the disconnector switch (DS) that may be at ground potential / housing potential, resulting in internal sparking and failure of the DS.

[0047] Therefore, according to an embodiment of the present disclosure, a disconnecting switch 300 for an electrical device 200 is provided, the disconnecting switch being designed to center the spark toward the longitudinal central axis of the first contact 310.

[0048] like Figure 3As shown, the disconnector 300 includes a first contact 310 and a second contact 320. The first contact 310 is tubular in shape with a longitudinal central axis. The first contact 310 can be movably arranged in the direction of the longitudinal central axis, and the second contact 320 can be a fixed contact. The first contact 310 is connected to the second contact 320 in the closed position. The first contact 310 is disconnected from the second contact 320 in the open position. The first contact 310 may have an end face pointing towards the second contact 320. The first contact 310 and the second contact 320 can be placed in an enclosed chamber. In some examples, the enclosed chamber may include an eco-friendly gas mixture. Some examples of eco-friendly gas mixtures may include nitrogen (N2), oxygen (O2), carbon dioxide (CO2), or fluoroketones or fluoronitriles and mixtures thereof.

[0049] In some embodiments, the disconnector 300 includes a dielectric shield (not shown) surrounding the first contact 310.

[0050] At least one of the first contact 310 and the second contact 320 may be movable in a direction along the longitudinal central axis of the first contact 310. In one example, the longitudinal central axis of the first contact 310 is the same as the longitudinal central axis of the disconnector 300. The longitudinal central axis is an imaginary line passing through the center of mass of a cross-section along the major axis of any object. In another example, the longitudinal central axis may be the axis of rotation of the first contact 310.

[0051] Furthermore, at least one of the first contact 310 and the second contact 320 of the disconnector switch 300 includes a predetermined contact portion 325. In the embodiments disclosed herein, the second contact 320 is considered to include a predetermined contact portion 320 having a roughness higher than that of adjacent contact portions of the second contact 320. In the open position, the predetermined contact portion 325 of the second contact 320 is closer to the first contact 310 than the adjacent contact portions of the second contact 320. The adjacent contact portions can be the remaining portions of the second contact 320 other than the predetermined contact portion 325. The predetermined contact portion 325 can be positioned closer to the longitudinal central axis of the first contact 310 than the adjacent contact portions. In one example, the predetermined contact portion 325 can be located at the end of the first contact 310 such that the predetermined contact portion 325 of the second contact 320 is closer to the first contact 310 than the adjacent contact portions of the second contact 320.

[0052] In some examples, the minimum roughness of the predetermined contact portion 325 of the second contact 320 has an arithmetic mean roughness value Ra of 1 micrometer, a total height Rt of 8 micrometers for the roughness profile, and an average roughness depth Rz of 4 micrometers. In some examples, the minimum roughness of the predetermined contact portion 325 of the second contact 320 has an arithmetic mean roughness value Ra of 2 micrometers, a total height Rt of 15 micrometers for the roughness profile, and an average roughness depth Rz of 7 micrometers.

[0053] In some examples, the minimum roughness of the predetermined contact portion 325 of the second contact 320 has an arithmetic mean roughness value Ra of 5 micrometers, a total height Rt of a roughness profile of 30 micrometers, and an average roughness depth Rz of 20 micrometers.

[0054] In some examples, the maximum roughness of the predetermined contact portion 325 of the second contact 320 has an arithmetic mean roughness value Ra of 20 micrometers, a total height Rt of a roughness profile of 120 micrometers, and an average roughness depth Rz of 80 micrometers.

[0055] In some examples, the maximum roughness of the predetermined contact portion 325 of the second contact 320 has an arithmetic mean roughness value Ra of 15 micrometers, a total height Rt of the roughness profile of 90 micrometers, and an average roughness depth Rz of 60 micrometers.

[0056] In some examples, the maximum roughness of the predetermined contact portion 325 of the second contact 320 has an arithmetic mean roughness value Ra of 10 micrometers, a total height Rt of the roughness profile of 60 micrometers, and an average roughness depth Rz of 40 micrometers.

[0057] In some examples, the roughness of the predetermined contact portion 325 can be increased by sandblasting the corresponding surface of the second contact 320. Sandblasting can be a mechanical surface treatment process that involves projecting spherical or granular abrasive particles onto the surface of a material at very high speeds. Furthermore, the predetermined contact portion 325 with increased roughness can be made of aluminum or an aluminum alloy. For surfaces under negative polarity, roughness can be increased at a rate that can increase electron injection by any means such as sandblasting. Additionally, metals with lower evaporation temperatures (such as aluminum) in gaseous insulators at rated filling pressures may not experience a moderating effect (reduced roughness) due to spark generation. Therefore, with increased roughness on the shield made of aluminum / aluminum alloy, the rate of negative ion entry onto the first contact 310 can be increased, where negative ions can detach from electrons to initiate a spark / discharge.

[0058] The position of the predetermined contact portion 325 can be defined as the center position on the second contact 320, and if positioned with the aid of the XY axis, xy% = 50%, and even more preferably xy% = 0%.

[0059] Furthermore, according to one example, the position of the predetermined contact portion 325 on the second contact 320 can be defined by field-line-ends, such that the field-line-ends begin at the moment of the first pre-breakdown at the axial center of the first contact 310, where xy% = 50%.

[0060] According to another example, the location of the increased roughness on the second contact 320 can be defined by the field line end, such that the field line end begins at the moment of the first pre-breakdown at the axial center of the first contact 310, where xy% = 30%.

[0061] Advantageously, by limiting the predetermined contact portion 325 to a specific location connected via the field line end toward the location where a spark / discharge may begin, the risk of a central spark / discharge under positive polarity is reduced.

[0062] For a spark / discharge to occur, an initial electron is required to initiate an electron avalanche. The second contact 320 is configured to initiate a spark or cause pre-breakdown and re-breakdown discharges from a specific region 330 on the inner surface of the first contact 310 during movement of the first contact 310, such as... Figure 3 As shown in the diagram. Spark initiation is achieved using negatively charged ions (…). Figure 3 This is achieved by targeted bombardment of a specific region 330 of the first contact 310 (not shown). Ions originate from a predetermined contact portion 325 of the second contact 320, thereby concentrating the spark / discharge path closer to the longitudinal central axis of the first contact 310. In one example, the specific region 330 of the first contact 310 is close to / near the center of the first contact 310, and the specific region 330 is the end of the first contact 310. Ions drift toward the specific region 330 of the first contact 310 along the direction of the electric field, and discharge is induced at the specific region 330 by increasing the field gradient at the specific region 330 to a value greater than the field gradient in other regions of the first contact 310.

[0063] Therefore, by inducing a discharge to begin at a predetermined contact portion 325 near the longitudinal central axis of the first contact 310, the spark / discharge generated between at least two contacts 310 and 320 is centered toward the longitudinal central axis. Advantageously, the risk of spark propagation is minimized, and thus the risk of DS failure is eliminated.

[0064] Figure 4A schematic diagram of an example cross-section of a disconnecting switch 300 suitable for electrical equipment 200 is disclosed. Electrical equipment 200 may be a disconnecting switch DS or any other similar switching device. The disconnecting switch 300 includes at least two contacts: a first contact 310, which may be a moving contact MC, and a second contact 320, which may be a fixed contact FC. In one example, MC 310 may be movable in the direction of the longitudinal central axis of the disconnecting switch 300. In one example, the longitudinal central axis of the disconnecting switch 300 is the same as the longitudinal central axis of the two contacts 310 and 320 (e.g., ...). Figure 4 (As shown in the diagram). MC 310 is connected to FC 320 in the closed position of DS and disconnected from FC 320 in the open position.

[0065] like Figure 4 As shown, when MC 310 begins to move or separates from FC 320, the spark (i.e., pre-breakdown or re-breakdown discharge) is drawn along with the movement of MC 310. FC 320 includes a predetermined contact portion 325 having a roughness higher than that of adjacent contact portions in FC 320. Adjacent contact portions may not be designed to have increased roughness. The predetermined contact portion 325 may be positioned closer to the longitudinal central axis of MC 310 than the adjacent contact portions. Furthermore, as... Figure 4 As shown, the predetermined contact portion 325 may be located at the end of FC 320, and therefore the predetermined contact portion 325 of FC 320 is closer to MC 310 than the adjacent contact portion of FC 320.

[0066] FC 320 is configured to: during the movement of MC 310, target and bombard a specific region 330 of MC 310 with negatively charged ions, allowing the ions to originate from a predetermined contact portion 325 of FC 320, thereby initiating a spark or causing pre-breakdown and re-breakdown discharge from the specific region 330 of MC 310. This concentrates the spark / discharge path closer to the longitudinal central axis of MC 310. MC 310 may have an end face pointing towards FC 320. In one example, the inner surface of MC 310 may be close to the center of MC 310 and may be the end of MC 310.

[0067] like Figure 4As shown, the thick arrow pointing from FC 320 to MC 310 indicates the path of ions generated at a predetermined contact portion 325 of FC 320. A path similar to the thick arrow is followed by negatively charged ions originating from the predetermined contact portion 325. Ion generation is initiated in the predetermined contact portion 325. The ions drift with the direction of the electric field existing between MC 310 and FC 320 to reach a specific region 330 on the inner surface of MC 310, where the ions increase the field gradient / electric field strength to induce a spark / discharge from the specific region 330. Therefore, spark initiation is achieved through targeted bombardment of negatively charged ions on the specific region 330 of MC 310. Since the predetermined contact portion 325 and the specific region 330 are located near the longitudinal central axis of the disconnector 300, the generated spark is concentrated.

[0068] Therefore, by increasing the roughness of the predetermined contact portion 325 and positioning the predetermined contact portion 325 closer to the longitudinal central axis of MC 310, the spark is displaced more towards the longitudinal central axis (i.e., towards the center of MC 310) and not towards the housing (i.e., the ground potential). As a result, any accidental contact between the spark and any other component of the electrical equipment 200 or DS is reduced, thereby eliminating the risk of failure of the electrical equipment 200 or DS. The longitudinal central axis is an imaginary line passing through the center of mass of a cross-section along the long axis of any object. In one example, the longitudinal central axis could be the axis of rotation of the first contact 310.

[0069] The foregoing description of the specific embodiments will fully reveal the general nature of the embodiments described herein, enabling others to readily modify and / or adjust various applications of such specific embodiments using present knowledge without departing from the general concept. Therefore, such modifications and adjustments should and are intended to be understood within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology used herein is for descriptive rather than limiting purposes. Thus, although the embodiments described herein have been based on preferred embodiments, those skilled in the art will recognize that the embodiments described herein can be practiced with modifications within the scope of this disclosure.

Claims

1. A disconnecting switch (300) for an electrical device (200), the disconnecting switch (300) comprising: The first contact (310) has a longitudinal central axis; as well as A second contact (320), wherein at least one of the first contact (310) and the second contact (320) is movable in the direction of the longitudinal central axis of the first contact (310), wherein the first contact (310) is connected to the second contact (320) in a closed position, wherein the first contact (310) is disconnected from the second contact (320) in an open position, wherein the second contact (320) includes a predetermined contact portion (325) having a roughness higher than that of an adjacent contact portion of the second contact (320), and wherein the predetermined contact portion (325) is closer to the longitudinal central axis of the first contact (310) than the adjacent contact portion.

2. The disconnector (300) according to any one of the preceding claims, wherein, The minimum roughness of the predetermined contact portion (325) of the second contact (320) has an arithmetic mean roughness value Ra of 1 micrometer, a total height Rt of the roughness profile of 8 micrometers, and an average roughness depth Rz of 4 micrometers.

3. The disconnector (300) according to claim 1, wherein, The minimum roughness of the predetermined contact portion (325) of the second contact (320) has an arithmetic mean roughness value Ra of 2 micrometers, a total height Rt of roughness profile of 15 micrometers, and an average roughness depth Rz of 7 micrometers.

4. The disconnector (300) according to claim 1, wherein, The minimum roughness of the predetermined contact portion (325) of the second contact (320) has an arithmetic mean roughness value Ra of 5 micrometers, a total height Rt of roughness profile of 30 micrometers, and an average roughness depth Rz of 20 micrometers.

5. The disconnector (300) according to any one of the preceding claims, wherein, The maximum roughness of the predetermined contact portion (325) of the second contact (320) has an arithmetic mean roughness value Ra of 20 micrometers, a total height Rt of roughness profile of 120 micrometers, and an average roughness depth Rz of 80 micrometers.

6. The disconnector (300) according to any one of claims 1 to 4, wherein, The maximum roughness of the predetermined contact portion (325) of the second contact (320) has an arithmetic mean roughness value Ra of 15 micrometers, a total height Rt of the roughness profile of 90 micrometers, and an average roughness depth Rz of 60 micrometers.

7. The disconnector (300) according to any one of claims 1 to 4, wherein, The maximum roughness of the predetermined contact portion (325) of the second contact (320) has an arithmetic mean roughness value Ra of 10 micrometers, a total height Rt of the roughness profile of 60 micrometers, and an average roughness depth Rz of 40 micrometers.

8. The disconnector (300) according to any one of the preceding claims, wherein, The first contact (310) has an end face pointing toward the second contact (320), and wherein, in the disconnected position, the predetermined contact portion (325) of the second contact (320) is closest to the first contact (310) compared to the adjacent contact portion of the second contact (320).

9. The disconnector (300) according to any one of the preceding claims, wherein, The first contact (310) is movably arranged in the direction of the longitudinal central axis, and wherein the second contact (320) is a fixed contact.

10. The disconnector (300) according to any one of the preceding claims, wherein, The predetermined contact portion (325) with increased roughness is made of aluminum alloy.

11. The disconnector (300) according to any one of the preceding claims, wherein, The predetermined contact portion (325) having the increased roughness is defined by a circular region having a central axis aligned with the longitudinal central axis of the first contact (310), and wherein the circular region has a radius smaller than the radius of the outer periphery of the first contact (310).

12. The disconnector (300) according to any one of claims 1 to 10, wherein, The radius of the predetermined contact portion (325) is smaller than the radius of the inner periphery of the first contact (310).

13. The disconnector (300) according to any of the preceding claims, comprising a dielectric shield surrounding the first contact (310).

14. The disconnector (300) according to any of the preceding claims, comprising an insulating medium between the first contact (310) and the second contact (320), wherein, The insulating medium includes at least one of sulfur hexafluoride (SF6), air, carbon dioxide (CO2), oxygen (O2), a mixture of fluorinated ketones, and a mixture of nitriles.

15. The disconnector (300) according to any of the preceding claims, wherein, One or more of the first contact (310) and the second contact (320) have a tubular shape.

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